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Compare And Contrast How Magmas Are Generated At Mid-Ocean
COMPARE AND CONTRAST HOW MAGMAS ARE GENERATED AT MID–OCEAN RIDGES
AND SUBDUCTION ZONES. According to Middlemost (1988)'s basic definition, magma is a
heated rock–forming substance that is created within a planet and exists only below Earth. When
magma escapes to the Earth's surface and is extruded, they are known as lavas. Grotzinger and
Jordan (2010) suggests that magma mainly comes from the asthenosphere– the upper part of the
mantle. Magmas are usually generated when rocks are under the right temperature and pressure
conditions to undergo partial melting (Grotzinger and Jordan, 2010). At high temperatures and low
enough pressures, rocks would reach its melting point easily. It is known for a fact that temperature
increases with depth ... Show more content on Helpwriting.net ...
Subduction zone magmas are formed by convergent plate boundaries between oceanic–continental
plates or oceanic–oceanic plates (at least one tectonic plate has to be oceanic) (see Fig.1). According
to Grotzinger and Jordan (2010), when the oceanic lithosphere gets subducted, there is fluid induced
melting occurring to the mantle wedge. Therefore, this generates magmas of varying composition.
From Prichard et al.'s findings, mid–ocean ridge magmas are usually basaltic in composition
whereas subduction zone magmas are andesitic and more silicic. Subduction zone magma
compositions also depend on the materials being subducted. Hence, in terms of chemical
composition, the subduction zone magmas and are definitely more varied compared to the mid–
ocean ridge magmas. Subduction zone magmas range from basaltic to rhyolitic– with andesitic
magmas being the most common (Grotzinger and Jordan, 2010). Fig.2 Geothermal gradient varying
in different geological settings: also showing the solidus for MOR and subduction zone mantle rock
MAGMA GENESIS Middlemost (1988) states that in the mantle at depths between 60–250 km (i.e.
the low–velocity zone), magma can be generated through either of the 3 ways; when you add
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Plate Tectonics: Birth Of A Theory
Based on the information in the textbook and the instructor note, plate tectonics is the Earth's
surface divided into several plates that move slowly and change in size. I found the video Plate
Tectonics: "Birth of a Theory" in session 13 very useful. It helps me understand the material easily
by using the animation to illustrate the process of plate tectonics. It is amazing about the fact that the
continents can be made to fit together like pieces of a picture puzzle. About 225 million years ago,
the Earth seemed to contain only one piece of continent. However, as time goes by, the plate
boundaries have happened. The plates that move away from one another are called divergent plate
boundaries. The plates that move toward each other are called
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SMT 312 Natural Disasters
Vitasta Vyas
Professor Cummings
SMT 312 Natural Disasters
January 31, 2018 Ring of Fire
An arc which spreads from New Zealand all the way to the west coast of North and South America
where three–quarters of world's volcanoes are found is called the Ring of Fire. According to the
scientists in the video plate tectonics play a very important role in forming of all the volcanoes. The
Ring of Fire is also famous for the earthquakes which takes place here. Ninety percent of the world's
earthquakes occur around the Pacific Rim, which is also an aftermath of shifting of plates. The
process that moves the rocks and the seawater into the Earth is called subduction. The scientists
explained the process of subduction through a 3D picture of the
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Oceanography Personal Statement
The ocean has always been of interest to me. Growing up in New Jersey, I have had the privilege to
go to the beach all throughout the year. This allowed me to see how the beach would change
throughout the seasons, making me aware that this was a dynamic environment. My family also
enjoyed going on vacations down south, which exposed me to different types of beaches. The
differences of the types of beaches always fascinated me, especially the sand. I wanted to learn why
the sands changed depending on where we were, and what composed the sand. As I have gotten
older, this curiosity of the different sands on the beaches has evolved, but I never thought of marine
sciences as a career choice until high school. I was never exposed to any formal education
surrounding marine science, besides the couple of lessons on marine animals during science classes
in grade school. It was not until junior year when I was placed in a class specifically related to
marine science that I discovered that I could take my curiosity of the ocean and explore it as a
career.
I am currently a sophomore at Stockton University studying oceanography and geology. I am
particularly interested in tectonics and mid–ocean ridges. I think it is extremely important to study
these ridge systems, as they ... Show more content on Helpwriting.net ...
I have the desire to learn as much as I can about geology and oceanography, and I believe earning
my doctorate is a great way in which to do this. After the completion of my doctorate, I would like
to go into research, specifically concerning mid–ocean ridges and plate tectonics. I hope that my
contributions will be able to help myself and other understand the processes that affect the Earth
more. Eventually, I would like to become a professor. I owe most of my interest in the marine
sciences due to the enthusiasm of my marine science teacher in high school, so I would like to
inspire students to pursue careers in the marine
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Submarine Volcanoes : The Most Important Type Of Submarine
SUBMARINE VOLCANOES
Sub marine volcanoes are fissures or vents present under water, through which magma comes out.
These submarine volcanoes are one of the principal dynamic forces acting on earth's crust.
The volcanic eruptions which take place under the surface of water at mid oceanic ridges,
subduction zones and within tectonic plates due to hotspots add up to produce submarine volcanoes.
Sub marine volcanoes are far mare superior to sub aerial volcanoes in terms of magma generation.
According to an estimate about 75% of total magma is formed at oceanic ridges.
The major fraction of these submarine volcanoes are deep seated in nature with some exceptions of
near shore volcanoes.
TECTONIC ENVIRONMENT OF SUBMARINE VOLCANISM:–
The eruptive nature of submarine volcanoes cannot be confirmed as these volcanoes are deep under
water. Some volcanologists believe explosive eruption is not possible due to high pressure created
by surrounding water.
Submarine volcanism takes place in different tectonic settings such as mid oceanic ridges, hotspots,
subduction zones and hydrothermal vents. Mid oceanic ridges are the most important type of
submarine eruption giving rise to mid oceanic ridge basalt or MORB. MORB covers about half of
Earth's surface, though in most places they are overlain by a thin layer of deep marine sediments.
The mid oceanic ridges are dominated by silent, gentle effusive volcanic activity and generate
remarkable quantity of lava sheets. Oceanic plateaus are also
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How Plate Tectonics Discovered
In this essay I will be telling you about plate tectonics. In my first paragraph, I will be talking about
how plate tectonics were discovered. Plate tectonics is theory that earth's outer shell divided into
severally. The mantle plates that glide over the mantle is the rocky inner layer above the core. The
plates act like a hard and rigid shell compared to earth's mantle.The strong outer layer is called
litosphere.
Developed from 1950's to 1970's, plate tectonics is the modern version of continental drift .This
theory was first proposed by scientist Alfred Wegener in 1912. Plate tectonics is the unifying theory
of geology that explains the structure of the earth's crust.
The earth's surface is broken into many different sections called plates.
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Eight Thousanders Research Paper
3. The "Eight–thousanders" are the 14 highest peaks in the world. These are the only mountains on
Earth which are at peaks of death zones. Death zones are areas where there is an insufficient amount
of oxygen available. These mountains are located on the Himalayan and Karakoram ranges in the
countries: China, India, Nepal and Pakistan (all in Asia). They are the only mountains to exceed
8,000 m above sea level. This height and the number of highest peaks drives climbers to an
obsession of climbing all of the mountains in a lifetime. These high peaks in the Himalayas are
mainly Fold Mountains which formed when two plates collided head on and the sides had pieces
breaking off. The two plates which collided were Asia and India, which formed these mountains.
The eight–thousanders are important globally because they help geologists figure out the story of
how processes have created mountains and their shape on the Earth. This story is of the 14
mountains began 40 million years ago when the subcontinent of India cam into a collision with Asia,
the edges of the collision created the rifts and valleys of the ranges. This is major for geologists as
well as they aid a lot in telling the physical processes of how mountains ... Show more content on
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This Mid Atlantic Ridge was discovered in the 1950s and is very important to the globe because the
discovery of the ridge led to the theory of seafloor spreading. Seafloor spreading is where new
ocean lithosphere gets created through eruptions and also how the basin of the ocean becomes wider.
Its discovery also allowed many people to accept Wegener's theory of the continental drift. The
Ridge separates the North American Plate form the Eurasian Plate in the Northern part of the ocean.
In the South Atlantic, the ridge separates the South American and African Plates. These plates
continue spreading, causing the Atlantic to
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Marine Volcanoes Vs Landforms
Submarine volcanoes, mid–ocean ridges, and submarine canyons are all grouped into the marine
geology systems. Underwater structures can actually be pretty useful to marine geologists, in 1930
studies found the seafloor to have all of the same physical features on land like mountains,
volcanoes, canyons and more. The seafloor is estimated to be less than 2,000,000 year old, being a
lot younger than landforms. The 'age' difference of the two makes marine geologists' work a lot
more fun to compare in finding the way rocks are built, how the sediments are compatible and
finding an estimated location of natural disasters underwater.
Submarine volcanoes, also known as sea mounts, are underwater landforms that magma releases
from. They're most commonly located near ocean ridges because that's where the most tectonic plate
movement happens therefore, more eruptions. Depending on the depth at which the volcano is,
vapor clouds may be visible but usually only in shallow waters. There are two big types of volcanic
eruptions, huge lava pockets that release really slowly and and bunch of little lava pockets that burst
super fast. There has been a study conducted so that scientists are able to differentiate the types of
eruption so that they know ... Show more content on Helpwriting.net ...
There are close to as many, or possibly equal amount of landforms as there are on the seafloor that
are just as important. In fact, there's an estimated 20 eruptions that happen annually through
submarine volcanoes and 80% of volcanoes are found under the ocean. One of the biggest mountain
ranges is the mid–oceanic ridge system, it connects in some way to every single ocean in the world
and is bigger than any other on land mountain range. Lastly, submarine canyons have opened up this
huge area of research that helps so much with oil discoveries and such. The seafloor is no less than
land and in most cases, the seabed is more useful to our research than landforms
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Mount St Helen Research Paper
Mount Saint Helen
The theory of the continental drift is that the continents have slowly drifted to their current location.
Alfred Wegener believed that all the seven continents were once a supercontinent known as Pangea.
A discovery that came from climate clues like glacial deposits in South America, Africa, Australia
and India. Rock and fossils matching evidence found in South America and Africa.
The theory of plate tectonics states that Earth's outer shell is divided into plates. The crust and upper
mantle is broken into plates that move around on the mantle, changing in size throughout time. The
lithosphere makes up the crust and upper mantle and the asthenosphere a plastic like layer beneath
the lithosphere. There are three types of plate boundaries. Divergent boundaries where two plates
move away from each other. The ocean widens and new crust forms at the mid–oceanic ridge.
Convergent boundaries has three types of converging, moving two plates towards each other. First
we have an ocean floor plate that collides with a less dense continental plate. Next an ocean floor
plate collides with another ocean floor plate. Finally a continental plate collides with another
continental plate. Transform boundaries were two plates slide past one another. The resulting effects
of plate tectonics is landforms such as rift valleys, ... Show more content on Helpwriting.net ...
Mount Saint Helen is located on The Ring of Fire, a zone of active volcanoes. In 1980 Mount Saint
Helen erupted due to its location on a destructive plate boundary where a continental plate (North
American) meets an oceanic plate (Juan de Fuca). Since the oceanic plate is denser it will submerge
under the continental plate. The plate melts because of friction between moving plates. The melted
plate is now magma which rise through the gaps in the continental plate, forming a volcano once it
reaches the
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The Theory Of Plate Tectonics
Plate Tectonics The theory of plate tectonics has been explored throughout history because of
similarities in coastal boundaries and other evidence found such as fossil records, geometric fit,
mountain episodes, the paleoclimate observed, information about the ocean floor, ancient
magnetism, distribution of volcanoes and earthquakes and heat flow from the earths core. There
were early theories from Wegner's continental drift which lacked an explanation for the mechanism
that drove the continents apart, to Wilson's more complete theory of the cyclical opening and closing
of the ocean basins due to movement of the earth's plates. The theory explains how today 's
continents were once a large supercontinent that slowly drifted to their present positions and will
again form one giant continent via collision.
According to the Natego film Colliding Continents, the landmasses are liable to drift back to each
other through plate tectonic activity. One of the few places on Earth where one can see continents
being pushed apart is in Iceland, where the mid–Atlantic ridge in shows above the surface and
shows how oceanic crust is made, the ridge in Iceland is almost three miles wide–on one side you
have the Eurasian plate and the other is the American plate. This rifts grows forming new rock and
causes the continents further apart widening the Atlantic Ocean moving about an inch a year. The
theory suggests that we go through cycles of dispersion and collision over a 100–million–year
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How Did Alfred Wegener Prove The Continental Drift
Alfred Wegener was a German Polar Researcher, geophysicist, and a meteorologist. He was born in
November of 1880, and later died in November of 1930. His theory for the continental drift was that
the continents had once been joined, called Pangea, and later drifted apart to form seven continents.
Alfred Wegener had to gather a lot of information to prove his theory correct.
The first supporting evidence Alfred found was how the continents were once connected. He was
not the only one to see this, but the one to actually prove this right. He first saw that Africa and
South America could connect, then he saw that all seven could do the same. He provided evidence
with showing, how animal, and plants were the same but on different continents. ... Show more
content on Helpwriting.net ...
For an example, there was once animals called, Cynognathus and Lystrosaurus. They were reptiles
that lived on land. Both of these animals were unable to swim at all, but their fossils have been
found across South America, Africa, India, and Antarctica.There was some fossils that supported the
theory of the continental drift. Some fossils were once connected, but then got separated with the
land they were on. Still, there was not enough evidence to support that Pangea once existed. To
conclude, Alfred Wegener was not going to give up on his theory of the Continental drift.
The last supporting evidence to Wegener's theory is rocks. Just like the fossils, there were rocks that
were once together, and they are now separated. Wengener didn't think this was a coincidence, he
knew that there was such a thing as the continental drift. To back this up, he found rocks that were
the same age, and type. He also connected mountain ranges to form one big mountain range. For an
example, he compared the Appalachian Mountains to mountain ranges in the Eastern Greenland,
Ireland, Great Britain, and
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Volcanic and Seismic Events as Proof of Plate Tectonic Theory
Volcanic and Seismic events are major pieces of evidence towards proving that plate tectonics
theory is valid.
A seismic event is the transient motion and release of kinetic energy caused by sudden failure of the
earth's crust, usually felt as shaking or tremors in the rock mass. Seismic events range in size from
barely perceptible tremors to major earthquakes. Volcanic events occur when there is a release of
magma, gas and ash from the Earth's crust.
The entire outer surface of the planet is divided into these plate formations with approximately 30 in
total. These different plates vary in size from over 100,000,000 square miles, for example The
Pacific Plate, to the Galapagos micro plate at 12,000 square miles. Fault lines separate each ... Show
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New Basaltic magma rises to the surface, cools and pushes the plates apart. The convection currents
also help drag the plates apart and then pull them down at convergent boundaries. This can be seen
at the mid–ocean ridges. Eruptions are non–violent with the exceptions of the East African Rift
Valley where the recent eruption in 2002 in the Republic of Congo had a devastating effect on the
local population, and where the ocean ridges rise up out of the sea such as in Iceland.
The theory of plate tectonics also explains the formation of destructive plate boundaries which
account for creating 80% of the world's active volcanoes. The melting crust at Subduction Zones
(oceanic–oceanic or continental–oceanic) are due to differences in density between oceanic and
continental lithospheres, where the less dense plate is pushed beneath the more dense plate, and
becomes part of the asthenosphere forming magma that is andesitic in its nature. This creates the
most violent volcanic activity. Island Arc volcanoes such as Pinatubo and Fold Mountain Volcanoes
such as Nevado Del Ruiz (Andes) are very destructive.
The evidence for deep, hot, convective currents combined with plate movement (and concurrent
continental drift) also explained the mid–plate "hot spot" formation of volcanic island chains for
example the Hawaiian Islands and the formation of rift valleys such as The Rift Valley of Africa.
Mid–plate earthquakes, such as the powerful New Madrid
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Axial Seamount Research Paper
The Axial Seamount is a very interesting landform. The Axial Seamount is an active volcano. Most
people might think volcanoes would be above ground however, this volcano is actually underwater.
The Axial Seamount was the site of the very first underwater volcano observatory. It is 300 miles
from the coast of Oregon and is 1400 miles deep.
The Axial Seamount is an underwater volcano. In the Northeast Pacific, it is actually the most active
underwater volcano. The volcano is on top of a divergent plate boundary. This volcano is on the
Juan De Fuca ridge and the Pacific Plate. This volcano is one of the best–studied volcanoes along
the global mid–ocean ridge (Interactive Oceans).
In 2011, Axial Seamount erupted. In 2006, Bill Chadwick who is a ... Show more content on
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Some landforms around the Axial Seamount art the Juan De Fuca ridge and plate, the Pacific Plate,
mid ocean ridges, subduction zones, and a caldera . A caldera is volcanic crater that is very big.
They can be made from two things, a very big volcanic eruption or rocks from the surface entering
an empty magma chamber. The Axial Seamount has a caldera at its summit.
I thought that the Axial Seamount was very interesting. One fact that I learned is that researchers
found out about the 2011 eruption by accident. The thought of finding something like that out is
funny. Another thing I found interesting is that if a ship was going over the seamount and it erupted,
no one on the ship would probably happen. I think it is crazy to have something big like that
happening under you, and you would have no idea it was happening.
Learning about the seamount was an interesting experience. The Axial Seamount is an active
volcano. It is on the Juan De Fuca and Pacific plate. The Seamount erupted in 2011 and was found
out about by accident. There are many landforms around the Seamount, one being a caldera. I
thought the Axial Seamount was very interesting and wish to study it more in
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Wegener's Fossils
The boat was being tossed upon the sea. The sails were torn from the harsh and unforgiving wind;
the cast about to snap in two. Alfred Wegener was observing his map to see if he was lost. All of the
sudden, something clicked. His eyes jotted back and forth on the paper as he discovered that the
continents all fit together like pieces of a puzzle. Could the continents have once been connected?
Wegener introduced his hypothesis to other scientists, but they rejected this proposal after no logical
explanation as to how the continents moved was provided. In circa 1960, another scientist, J. Tuzo
Wilson, decided to reintroduce Wegener's hypothesis. Scientist took interest this time around
because Wilson, and other scientists including Harry Hess, turned Wegener's hypothesis into a
scientific theory that explains that the continents moved, how they moved, and that they are still
moving today. A few crucial pieces of evidence that the continents moved are Wegener's
observations. Although scientists disregarded his studies, he did have pieces of substantial evidence
that the continents had moved. First is his evidence from fossils. Fossils are important because they
give traces of ancient organisms. If Wegener wanted to prove that the continents moved, fossils
would have to be included in his analysis. For example, the Lystrosaurus and Mesosaurus ... Show
more content on Helpwriting.net ...
Scientists were able to uncover the answer to this question through sea–floor spreading, or more
accurately, evidence from molten material, magnetic stripes, and drilling samples. It all starts at the
mid–ocean ridge, the longest chain of underwater mountains in the world. During the process of
sea–floor spreading, molten material rises from the mantle and erupts at the mid–ocean ridge. The
hot material spreads out, pushing away the cool, older, hardened material to both sides of the ridge,
ultimately expanding the ocean
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Chile 1960 Research Paper
In Valdivia, Chile 1960 an earthquake changed the lives of many. An earthquake is the violent
shaking of the ground that will destroy homes, buildings, landforms, historical monuments, and
lives. Earthquakes begin with the breakage of rock along a fault line. When two tectonic plates rub
against each other they create an earthquake. Earthquakes will ride along a fault line which will
determine how long the quake will go on. The larger and longer the fault like the bigger the
earthquake. Earthquakes send out waves, primary waves or, p waves and secondary waves or, s
waves travel along the interior of the earth. These two waves are called body waves. While detecting
the waves, the primary waves appear first then the secondary waves. Primary waves travel through
solids, liquids, and gasses, which means they are about to travel through the liquid center. Secondary
waves are only able to travel through solids which are why scientists have found that there is a loss
of these waves once they reach the center. ... Show more content on Helpwriting.net ...
Before the quake hit the day before, there were a series of shocks that tipped off to people of Chile
that something was coming. The day that the earthquake hit, it was a rated a 9.5 on the Richter
Scale. The intensity of this caused thousands of buildings to be destroyed and 2,000,000 people left
homeless. The population of the city had greatly decreased and the city also needed to pay for the
damage to be repaired. It would be 800 million American dollars to complete the cleanup and
repairs of the city almost completely. This earthquake was called "The Great Chilean Earthquake"
because of the total destruction and because of the expansion of it where other countries received the
aftershocks and effects. Japan had received a tsunami a day later, killing 138 people and leaving
1600 homes destroyed. Japan was left to pay 34 million dollars for damage
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Plate Tectonics Research Paper
Have you ever wondered why our continents are in the positions that they are in today? Plate
Tectonics can be used to explain the movement of the plates and the landforms they make. These
landforms include mountains, volcanoes, rift valleys, and much more that are made by convergent
and divergent boundaries. The plates are moved by the convection currents below the surface which
is caused by a heat source, the mantle. Another landform that is made is a mid–ocean ridge, at which
sea floor spreading is taken place, and allows magma to rise and harden on the ocean floor.
Two different types of landforms that form at convergent boundaries are mountains and volcanoes.
Mountains, such as Mount Everest and K2, are formed when two continental plates collide, which
causes the landforms to rise. Volcanoes, such as Mount Saint Helens and Mount Fuji, forms when
the more dense oceanic plate subducts under the less dense continental plate and is driven down into
the hot asthenosphere. Subducted plate melts due to extreme heat and friction. Melted plate rises up
through the crust, where it reaches the surface and cools. Those weak spots allow the magma to
come out, forming into lava. There are also volcanic island arcs, which form when two oceanic
plates collide, and continental volcanic arcs, which forms when an ... Show more content on
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Mid–Ocean Ridges, such as the Mid–Atlantic Ridge, are formed when two oceanic plates move
away from each other, allowing magma to rise up from inside the Earth. The magma reaches the
bottom of the ocean, turns into lava and cools, forming new rock. This cycle continues constantly
spreading the sea floor and adding new material along this chain of mountains. Rift Valleys, such as
Baikal Rift Valley, are formed when two continental plates move away from each other, stretching
out the crust, until it begins to break. As crust is stretched wider, the valley drops
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Volcanic and Seismic Events Are Major Pieces of Evidence...
Volcanic and Seismic events are major pieces of evidence towards proving that plate tectonics
theory is valid (40 marks) The theory of plate tectonics states that the Earth's lithosphere (top layer
of the Earth's crust) is split up into rigid sections called plates that are moving relative to one
another as they move on top of the underlying semi–molten mantle. These plates are either
continental, The North American Plate, or oceanic, The Nazca Plate. Tectonic plates are powered by
convection currents, which is the circular movement of magma within the mantle. These currents are
powered by the core, which heats the magma, causing it to rise, cool and fall back down. This
circular motion causes the plates, which float on the mantle, to ... Show more content on
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Earthquakes can be created on any of the plate boundaries. Earthquakes occur when tension is
released from inside the crust. Plates do not always move smoothly alongside each other and
sometimes get stuck. When this happens pressure builds up. When this pressure is eventually
released, an earthquake tends to occur. The point inside the crust where the pressure is released is
called the focus. The point on the Earth's surface above the focus is called the epicentre. Earthquake
energy is released in seismic waves. These waves spread out from the focus. The waves are felt most
strongly at the epicentre, becoming less strong as they travel further away. The most severe damage
caused by an earthquake will happen close to the epicentre. But there are some anomalies as there
are earthquakes which don't take place on a plate boundary and it's the same with volcanoes. An
example of this is Hawaii. Hawaii is a volcanic island which is found in the middle of a tectonic
plate. Hawaii is an example of a hotspot. The places known as hotspots are volcanic regions thought
to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. They
may be on, near to, or far from tectonic plate boundaries. There are two hypotheses to explain them.
One suggests that they are due to hot mantle plumes that rise from the core–mantle boundary. The
other hypothesis postulates that it is not high
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The Theory Of Plate Tectonics
Plate tectonics is the theory that the Earth's crust is divided into large and small plates that move
slowly over time. The Earth's lithosphere is made up eight major plates which include the Africa
Plate, Antarctic Plate, Indo–Australian Plate, Australian Plate, Eurasian Plate, North American Plate,
South American Plate, and the Pacific Plate. Earth also has dozens of smaller, minor plates (Plate
Boundaries). Scientists used this theory to explain what is happening on Earth's surface. The
movement of plate tectonics creates many plate boundaries that have formed landscape features we
see on Earth today such as volcanoes and mountains among many other features. The theory of plate
tectonics helped geologists to apprehend how the continents are in the position that they are today as
well as how landscape features are created. The theory of continental drift is that all of the world's
continents were once a single continent called Pangaea, which slowly drifted apart over time
forming the seven continents that we have today. This theory was proposed by Alfred Wegener, a
German Meteorologist, in 1912. Wegener gathered several pieces of evidence that supported his
theory of continental drift. Wegener's first piece of evidence was that the shape of Earth's continents
seem to fit together like a jigsaw puzzle. For example, Africa's West Coast nearly fit with South
America's East Coast. A second piece of evidence that supported Wegener's theory are glacial till
deposits
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GEPlateTectonicsAnswers
Adapted from an activity by
Laurel Goodell
February 2013
Introduction to Plate Tectonics via Google Earth (24 pts)
B. Topographic Patterns
Uncheck all of the layers and focus on topographic features of the earth.
Topography of the earth ABOVE sea level
Questions
Answers
1. Are mountains randomly distributed on the continents, or do they tend to occur in particular
patterns (clusters, linear chains, arcs, etc.)?
Some appear in lines and others in arcs
1pt
2. Find Mt. Everest, the highest point on earth. Zoom in enough to see the summit, then pan your
cursor around to locate the 8840_______ meters highest point (elevations shows up in the status bar
at the bottom, as long as
View/Status Bar is selected):
1pt
Adapted from an activity ... Show more content on Helpwriting.net ...
Be sure to consider topography/bathymetry as well as the earthquake and volcano layers. List
several ways and be specific.
3pts
In the middle between the two
Without the plate boundary feature, you would still see the change in depth where the mountains
are, still feel earthquakes, and see volcanic eruptions.
Adapted from an activity by
Laurel Goodell
February 2013
Mid–Atlantic Ridge
F. Plate motion
Motion across the mid–Atlantic ridge: the South American plate vs. the
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Chapter 2
STUDY GUIDE: Chaps. 2 GEOL 111G–Survey of Geology At the end of each chapter are Review
Questions and Key Terms. To study for the final, be sure to know the answers (or where to find the
answers) for the given review question numbers and know the definitions of the key terms indicated.
The Key Terms have page numbers for reference in the textbook. CHAPTER 2 Review Questions:
#'s are based upon the 10th edition. These may be different in older or newer editions. 2. What was
the first line of evidence that led early investigators to suspect that the continents were once
connected? The puzzle–like fit of the continents, especially Africa and South America. 3. What was
Pangaea? Pangaea, the supercontinent named by Alfred Wegener, is ... Show more content on
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However, if you travel away from the ridges you will encounter rocks with reverse polarity and then
rocks of normal polarity which are followed by reverse polarity rocks, etc. Vine and Matthews
observed that there were symmetrical bands of rocks with similar polarities on each side of every
mid–ocean ridge. They hypothesized that the reverse polarized rocks formed at the ridges during the
geologic past when the earth's magnetic field had reverse polarization. Their work provided rather
elegant proof that the seafloor spreading actually occurs. 11. Compare and contrast the lithosphere
and the asthenosphere. –Both in the mantle. –Lithosphere is Earth's crust and at 100–150 km of the
mantle. –Asthenosphere is in the upper mantle. –Lithosphere is relatively rigid while asthenosphere
has low rigidity. –Asthenosphere acts as a lubricant. –Plates in the lithosphere move because of
asthenosphere. 12. List the three types of plate boundaries and describe the relative motion at each
of them. Divergent boundaries–where plates are moving apart Convergent boundaries–where plates
are moving together Transform boundaries–where plates slide past one another along faults 13.
Where does new lithosphere form? Where is it consumed? Why does the rate at which new
lithosphere forms roughly balance the rate at which lithosphere is destroyed. Elevated position of
the oceanic ridge, increase in ocean depths away from
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Memorable Experience
The Memorable Experience
When I was teenage life ,my special someone say I have my entire life ahead of me, with all of its
best experiences I had. But despite being a teenager, I already have a personal breath taking
experience, for hike and the mountain which I am sure I will carry with me until my last days my
first hike to the mountains
traveling is not a big deal for me today, before my trip to the mountains, I used to be a homebody. I
had special someone to hang out with, several hobbies, and I feel completely comfortable spending
weeks or even months in my hometown sometimes even on my block without going anywhere. All
my demands of novelty were satisfied by the Discovery the wild life and the mountain, and I
seriously thought ... Show more content on Helpwriting.net ...
The same fog was covering the surroundings, and even though I was teeming with positive
emotions, I feel disappointed, because I counted on seeing the view from above and perhaps being
able to take some photos. We spent a couple of hours on the top, and decided to turn back, when the
wind suddenly dispersed the clouds, and the plateau we were standing on became illuminated with
the sun. I saw a fantastic skies and clouds in front of me, and for some moments I couldn't believe
my eyes. Seeing all those mountain ridges, cliffs, and edges on my own eyes, not on TELEVESION,
INTERNET was like a revelation for me. The strong wind blew right into my face, and I just stood
there and watched shreds of fog gliding over the ground far beneath me. At that moments, that I can
realized that I won't be able to lives a life without visiting and seeing the beautiful mountains at least
One a year or twice a year and I told Joana, to stay for few hours and watched the sunset before
waiting the sunset When I saw Joana how excited and I suggested where going have a picnic and I
get the foods and drinks When we finished eating ,before we leave can 't be walk around and I said
to Joana how great of a time I had with him after
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The Theory Of Plate Tectonics And Earth 's Crust Displacement
For millions of years the Earth has experienced geologic catastrophes. Since the existence of Theia
itself, the Earth's crust has been formed, deformed, and even demolished. The crust has never been a
completed masterpiece due to this. Why is this? The most recent physical changes were caused by
the theory of plate tectonics and earth's crust displacement. Plate tectonics and its movement
resulted in our continents drifting across the earth's surface, and the creation of mountain belts,
volcanoes, and the faults of today's Earth. A German meteorologist and explorer Alfred Wegener put
forth the theory of continental drift in the early 1900's. Wegener pointed out that the earth's
continents looked as if they were all connected at one point in time. He also pointed out that some of
earth's features, including the long S–shaped mountain structure formed on the Atlantic seafloor,
could fit snugly against the corresponding western seafloor of Europe and Africa (Sieh and LeVay
1998). Wegener proposed that all of the earth's continents once formed one single landmass, which
he named Pangaea or "all–land". He concluded that Pangaea had broken up and separated due to the
unidentifiable forces estimated 300 million years ago (Sieh and LeVay 1998). Geologists did not
fully understand at the time that Earth's continents could drift (Hazen 2012). After all, the continents
do not float in the oceans. They are made from a solid material connecting to the mantle, a sphere of
solid rock
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Types And Regional Distribution And Frequency Of...
i. Abstract Numerous extinct spreading centres are found within the world's ocean basins and these
record instances of spreading cessation or migration that provide valuable insights into the
mechanism of heat–loss from the mantle and plate tectonic behaviour. This study presents the first
comprehensive review of all reported extinct ridges and investigates their characteristics and
regional distribution and frequency of occurrence over the last ~170 Myr as recorded in present–day
preserved oceanic crust. The axial morphology, gravity signal and crustal structure of extinct ridges
are evaluated by generating across–axis profiles through global datasets (IHO – IOC 2014; Sandwell
et al. 2014) for individual ridge segments. Information on the spreading–rates, time of cessation and
duration of spreading prior to cessation was collating information from previous studies. The
potential geodynamic influences on the lifespan and activity of mid–ocean ridges were investigated
by evaluating the relationship of extinct ridges to hotspots at their time of extinction using GPlates
(Boyden et al. 2011) and a global reconstruction (Seton et al. 2012). Global examples are
investigated to assess similarities or differences and to determine the 'characteristic' signal of extinct
ridges. Ridges were classified according to the quality of constraints into a primary, secondary or
tertiary tier that dictated their inclusion in the quantitative analysis undertaken. Spreading centre
subtype is
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The theory of sea- floor spreading was introduced by Herny...
The theory of sea– floor spreading was introduced by Herny Hess in 1960s. Hess came with the idea
that new oceanic floor formed at the mid oceanic ridges. Ridges is a crack in the earth's crust
through which spreads rock rises to the surface. The Melton rock spreads out and adds new material
to the ocean floor. The new materials are carried away from the mid oceanic ridges. Sea floor
spreading explains the existence of pillow lava near the ridges and the absence of thick layers of
sediments on the ocean floor. In fact, near the ridges, sediment is not found. One of the most
important contributions of the theory of sea– floor spreading was that it could explain how continent
moved. (Silver Burdelt & Ginn 301–302)
Sea– floor ... Show more content on Helpwriting.net ...
If the sea floor spreading is not taking place all rocks found in the oceanic crust they must have
same age and structure. Therefore due to the sea– floor spreading made variation of rock from the
middle part of oceanic ridge to the part found far away it
Formation of new oceanic crust at the mid– oceanic ridge; this also proves the theory of sea– floor
spreading at the mid– oceanic ridge. The oldest one must move away from mid oceanic ridge to
allow upwelling of molten materials. Molten materials later cool and solidify to form new oceanic
crust. At the spreading centre liquid rock called basalt magma rises from the Earth's mante as it up
wells beneath the spreading axis. When the magma hardness it forms crust that becomes welded to
the original crust ( Encyclopedia Geology and Oceanograph Accumulation of sediments / Fossil as
we look at these deposits– burned fossils and sediments, we will see older and older fossils as we
move further and further from the mid– oceanic ridge as the results we will see greatest proportion
of extinct species. Also sediments much deposit on the older part of the sea floor for longer than
new parts around the mid oceanic ridge. Different sediments tend to accumulate on different parts of
oceanic floor if the ocean floor stayed still then the other things being equal, we would expect same
deposit of the sediments from any particular place on sea –floor to be pretty much the same all the
way down. Sea
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How Old Is The Oldest Oceanic Crust
Questions: 1) How old is the oldest oceanic crust in the:
Indian Ocean: 150 million years old
Atlantic Ocean: 180 million years old it's typically the same age as the Pacific Ocean Pacific Ocean:
180 million years
2) How old is the oceanic crust that is found along the coastline of Northern California?
The oceanic crust found along the coastline of Northern California is about 30 million years old.
3) In the Pacific Ocean, where is the oldest oceanic crust located (generally)? The oldest oceanic
crust is located along the continental margin,
Which is composed mainly of the continental shelf, continental slope and continental rise.
4) In the Pacific Ocean, where is the youngest oceanic crust located?
The youngest oceanic crust is located along the mid–ocean ridges where new crust is formed when
the old crust is pushed away from mid – ocean ridges as a result of the seafloor spreading.
5) In general terms, describe the distribution of youngest and oldest crust in the Atlantic Ocean
Basin.
The color red represents the youngest crust in the Atlantic Ocean. The youngest crust is formed
when two or more plates diverge in the mid–ocean ridges. The color blue, green and yellow are
older crusts that are pushed away from the mid–ocean ridges when the youngest crust is formed,
which is referred to as the sea floor spreading. 6) Look the Pacific Ocean Basin and compare it to
the Atlantic. Specifically look at the oldest / youngest oceanic crust
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Mid-Atlantic Ridge Vs Volcanic Trench
from each other as magma pushes up in the rift valley. The Mid–Atlantic Ridge is just a small
portion of the mid–ocean ridge which encircles the Earth. Another boundary is called a convergent
boundary. When the crust expands at the divergent boundary the plate is pushed into another plate
where it is either sub–ducted or it buckles. This really depends on the type of lithosphere that is
involved in the convergence (Kious). This convergence can occur between two ocean plates, two
continental plates or an ocean and continental plates. Two of the features that can be found at a
convergence boundary is a volcanic arc and a deep ocean trench. The Volcanic trench can be found
over the subduction zone (Trujillo, pg 55). When an oceanic plate
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Proving Pangaea Existence Proven
Pangaea Existence Proven Have you ever heard of Pangaea? Do you think it is real? Do you need
someone to prove it for you? Well,I am here to prove Pangaea's existence to you. To begin with, you
need to know what Pangaea is. Pangaea was thought of in the year of 1912. This theory was called
Continental Drift and was proposed by Alfred Wegener.Pangaea was thought to be a Super
Continent. When Alfred Wegener proposed this theory no one really believed him because he did
not have much proof. This proof brings me into my topic "Pangaea Existence Proven". To start off
with fossils that were from, for example,Europe were found in, for example, North America. This is
a good reason because i do not think
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Theories Of Plate Tectonics
Plate Tectonics have been recently discovered. Earthquakes and volcanoes can now be located and
the public can find out when it will erupt or occur. Our earth has a fragile shell, which moves around
recycling itself, to form new layers of crust.The theory of plate tectonics was helped develop by the
theory of plate tectonics. Convection currents and gravitational forces move tectonic plates. The
contact between plates, creates earthquakes, volcanoes, islands and mid ocean ridges. Mountain
ranges, are examples of converging plates and modern technology can help scientists locate tumours
or movement in the Earth.–Thesis–Convection currents and Plate tectonics explains global
anomalies and phenomenon like earthquakes, volcanoes, mid ocean ridges ... Show more content on
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This then send out a massive wave of energy through solid rock and water. This then results to the
ground and water shaking, as the massive wave of energy passes through. The ring of fire is where
90% of all recorded earthquakes have occurred. Most earthquakes form near the plate boundaries.
The most strongest earthquakes have been near converging boundaries. The location of the different
earthquakes can help explain and give further information for the theory of plate tectonics and
where the boundaries for different plates
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Seafloor Spread Research Paper
Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could
not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry
Hess confirmed Wegener's ideas by using the evidence of seafloor spreading to explain what moved
continents. The theory of plate tectonics is what brings together continental drift and seafloor
spreading. Plates are made of lithosphere topped with oceanic and/or continental crust. The plates
are moved around on Earth's surface by seafloor spreading. convection in the mantle drives seafloor
spreading. Oceanic crust is created at mid–ocean ridges. The crust moves outward from the ridge
over time. The crust may eventually sink into the mantle and be
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Continental Drift
One line of evidence used to support continental drift is the discovery of similar fossils on different
continents. Both fossil plants and animals found in India, South Africa, Australia, Antarctica, and
South America are very similar. This supports the idea that the continents were once one because it
suggests that the animals roamed the land, were fossilized where they were when they died, and then
we discovered the fossils after the supercontinent had separated. Another line of evidence that
supports the drifting of continents is geological similarities between western Africa and eastern
South America. Mountain ranges in Buenos Aires, Argentina and mountain ranges in western Africa
are similar. There are also mountain ranges that extend
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The Spreading Of Iceland All Occurs On The Mid Atlantic Ridge
The seafloor spreading in Iceland all occurs on the mid–Atlantic ridge. Iceland emerged as a result
of the divergent spreading and the boundary between the two tectonic plates and the activity of
Iceland's own hotspot or mantle flume. Movement of these plates caused earthquakes and
volcanism. This allowed Iceland to be the largest portion of the mid– ocean ridge system that is
above sea level. The beginning of the start of sea floor spreading in Iceland occurred about sixty
million years ago when the North–Atlantic Ocean began to open. At this time, the North American
plate along with the Eurasian plate moved east and westward at approximately one centimeter per
year in each direction. This has created new basalt, and ninety–two percent of Iceland's surface area
is made up of basalt. The Mid–Atlantic Ridge contains a series of spreading centers showing the
ridge crest, offset in numerous areas located near transform faults that illustrate the seismically
active parts of fracture zones. The dating of spreading has been recorded by magnetic lineaments,
with magnetic observations from the ocean floor south of Iceland being taken advantage of in the
early understanding of the ideas of plate tectonics. The largest offset is the Charlie–Gibbs Fracture
Zone in the south of Iceland, where it is offset at three–hundred and fifty kilometers. To the north of
this area is where the ridge is relatively straight and the depth of the water decreases at a constant
rate towards Iceland. At
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Mid Ocean Ridges Research Paper
Welcome to one of the planets most obscure but important features, known rather prosaically as the
mid ocean ridges. In 1973 a group of oceanographers discovered this ridge of mountains on the
ocean's floor. Since then, they have been more closely exploring the ridges and studying how they
move and exactly what they are. They have come to discover, that the "ridges feature long rift
valleys and, down their middles, giant fields of gushing, hot springs that shed tons of minerals into
icy sea water at the bottom of the sea," which over time has come to create these huge mid–ocean
ridges where many animals like to live, cause its some warm." A main question is to what extent the
volcanism changes over time. The old idea was that the eruptions
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Interglacials
Similar fluctuations in deep water formation during interglacials have been recorded in the Southern
Ocean (Hayes et al. 2014). A peak in authigenic uranium was recorded in Southern Ocean
sediments, at OPD site 1094, 127,000 years ago, during Marine Isotope Stage 5 (Hayes et al. 2014).
At the beginning of this interglacial period, ~135,000 years ago, a sharp increase in biogenic opal
flux was recorded, reflecting an increase in productivity in the Southern Ocean (Hayes et al. 2014).
Oxygenation of the deep water increased with increasing Southern Ocean overturning, leading to a
gradual reduction in authigenic uranium concentrations (Hayes et al. 2014). The authigenic uranium
peak recorded at ~127,000 years ago, Marine Isotope Stage 5e, was ... Show more content on
Helpwriting.net ...
2014). When age model uncertainties are taken into account, this δ13C decrease at ODP site 1094 is
synchronous with a δ13C decrease at ODP site 1089 (Hayes et al. 2014, Galaasen et al. 2014). This
highlights the bipolar seesaw at work during this interglacial period, via alternating fluctuations in
both the formation of Antarctic Bottom water and North Atlantic Deep Water (Hayes et al. 2014).
Summary The 'leak' in the biological pump in the Southern Ocean can be influenced by a variety of
processes, changing the Southern Ocean's influence on the concentration of atmospheric CO2, and
global climate over glacial–interglacial timescales (Sigman et al. 2010). Reduced ventilation in the
Antarctic, as a result of decreased Antarctic Bottom Water formation, decreases the amount of CO2
released to the atmosphere and increases the storage of CO2 in the deep ocean (Sigman et al. 2010,
Hayes et al. 2014, Galaasen et al. 2014). Increased sea ice coverage would have also limited the
release of CO2 to the atmosphere during glacial periods (Sigman et al. 2010). Greater nutrient
utilization due to increased supply of Fe either by upwelling or dust input would lead to greater rates
of CO2 sequestration in the deep ocean (Sigman et al. 2010). Increased productivity in the
Subantarctic Zone during glacial periods, coupled with reduced Antarctic overturning would have
also increased the amount of carbon in
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U3A5: The Evidence Of Moving Continents
SES4U4–A
10/14/2015
Mr. Ramphal
Streetsville Secondary School
U3A5 – Evidence of Moving Continents
The Movement of Continents
Introduction
How do we know that continents can move across vast distances over a long enough period of time?
It is very hard to imagine what amounts to 150 million kilometers squared of land that we have on
the earth moving such an incredible distance. This was the main idea opposing the Continental Shift
theory: there were no known forces strong enough to move entire continents against the massive
force of friction, and even today many geologists are unsure whether the weaker force of the Earth's
convection causes the shift, or the stronger gravity. Alfred Wegener, a German scientist, proposed
that ... Show more content on Helpwriting.net ...
In general, magnetic minerals such as magnetite and hematite are studied to gain more insight on
our magnetic field. When the minerals are formed, their magnetism is lined up with the Earth's. This
important, and many times, permanent, form of evidence can help scientists understand the history
of the rock formations in question. The magnetism can not only be used to understand the past
rotation of continents, but also the latitude that the rock formed at. This is due to the inclination of
the specific magnetic field. The inclinations of the lines of force of the magnetic field get steeper at
higher latitudes near the geographic North Pole (top of the axis of rotation of the earth), as well as
the geographic South Pole. This vital fact lets scientists determine North–South motions of the past
locales of the Earth's continents. An important distinction that they found between today and the
past is difference in positioning between the current magnetic North Pole and the one in the past. In
the present day, groupings of minerals dated to the same time period at specific continents have
common magnetic field characteristics, and their fields are often not lined up with our current
Magnetic North pole. The older the minerals, the more drastic difference they have between our
current Magnetic North. Scientists can calculate from this that these large groups of minerals, the
continents, must have moved over time so that their magnetic fields were different in the past. Also,
when comparing different continents they found that the pathways were strikingly different,
indicating local changes in trends. Therefore, the differing magnetic fields of minerals found within
our continents can help prove the theory of Continental
... Get more on HelpWriting.net ...
San Andreas Fault In California
San Andreas fault in California
The San Andreas fault line is one of the most notorious faults in the world where it lies
approximately 1,287 km long in California, USA. Fault lines are cracks in the Earths surface, where
earthquakes usually occur.
The San Andreas fault in California is a transform boundary which means the tectonic plates grind
against each other slowly building up tension through friction then one day they'll slip causing an
earthquake to occur.
Since the San Andreas fault is a transform boundary, earthquakes occur along its fault which will
affect California and anywhere that the strength of the earthquake can reach making the fault a
seismic hazard to those who live there. The San Andreas fault is home to thousands of
... Get more on HelpWriting.net ...
Continental Drift and Plate Tectonics
Continental Drift and Plate Tectonics Theory (Part 1a) Introduction: The Beginning of the
"Continental Drift Theory" In the middle of the eighteenth century, James Hutton proposed a theory,
uniformitarianism; "the present is the key to the past". It held that processes such as geologic forces–
gradual and catastrophic–occurring in the present were the same that operated in the past. (Matt
Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed
by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and
Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered
that the coasts of the eastern part of South America and the ... Show more content on
Helpwriting.net ...
Water from the south then flowed in over time, thus forming the evaporites now found along the
coastlines there. (Lois Van Wagner, 2013)(Figure 5) However, Wegener believed that only the
continents were moving and they plowed through the rocks of the ocean basins. (Colliers
Encyclopedia, 1996) Harold Jeffreys then argued that it is impossible for continents to break through
solid rock without breaking apart. (USGS, 2012) Wegener also claimed that the centrifugal force of
the spinning planet had forced the continents sideways, parallel to the equator; tidal pull from the
sun and moon had caused lateral movement. (Sant, Joseph, 2012) His orders of magnitude were too
weak. Thus, his theory was dismissed. (Lois Van Wagner, 2013) Further development and support of
the "Continental Drift Theory" in the 1960s After World War 2, the U.S. Office of Naval Research
intensified efforts in ocean–floor mapping, leading to the discovery of the Mid–Atlantic Ridge to be
part of a continous system of mid–oceanic ridges on all ocean floors, prompting Harry H. Hess to
suggest the theory of sea–floor spreading. The oldest fossils found in ocean sediments were only
180 million years old and little sediment were accumulated on the ocean floor. Thus, he suggested
that seafloors were no more than a few hundred million years old, significantly younger than
continental land due to
... Get more on HelpWriting.net ...
Tectonic Plates
The Earth is a very detailed planet; there are many actions going on at once on this planet. The Earth
has many boundaries, plates. and layers. The plates beneath our feet mold the world we live in.
While very slowly, the plates are indeed moving. There are a few variations to the plates; they have
different directions in which they move in relation to separate plates. These changes in plate
movement have different side effects, from ocean trenches to miles of mountain ranges. In 1912, a
german climatologist, Alfred Wegener proposed that the continents were once joined and made one
land mass. He named this super continent Pangaea. He had a lot of evidence to prove that they were
once together, but he was missing one key section of information, ... Show more content on
Helpwriting.net ...
Each plate is moving a certain direction due to the convection from the Asthenosphere. The meeting
of two plates is called a boundary, there are three types of boundaries in the world: Convergent
Boundaries, Divergent Boundaries. And Transform Boundaries. In the case of Convergent
Boundaries, two plates are pushing against each other, which can create Deep Ocean Trenches,
Huge Mountains, and/or Volcanic Mountain chains. An example of this happening is the Mariana
Trench, During Convergence, the denser crust, oceanic crust, is subducted below the less dense
crust. If the crusts have the same density then the plates are pushed upwards. At Divergent
Boundaries, the plates are moving away from each other, this can create Mid–Ocean Ridges and Rift
Valleys. An example of this happening is the Mid–Atlantic Ridge. At the final boundary, Transform
Boundaries, the plates slide the past one another in the opposite direction, causing shallow
earthquakes and offset features. An example of this Boundary is The San Andreas Fault. While the
crust moves, there are places called Hot spots in which a hot portion of the mantle rises up beneath
the crust for millions of years. An example of this is the Hawaii Island
... Get more on HelpWriting.net ...
The Current Shape Of Earths Landmasses Was First Proposed...
Question 1 The idea of Continental Drift to explain the current shape of Earths landmasses was first
proposed by Abraham Ortelius in 1596. He proposed the idea to highlight the geometrical
coincidences between America and Europe–Africa. In his work Thesaurus Geographicus he
suggested that the Americas were "torn away from Europe and Africa...by earthquakes and floods",
and that "the vestiges of rupture reveal themselves, if someone brings forward a map of the world
and considers carefully the coasts of the three." Antonio Snider–Pellegrini was a French geographer
and scientist who theorized the possibility of continental drift several decades before Alfred
Wegener in his publication The Creation and its Mysteries Unveiled. He came to this ... Show more
content on Helpwriting.net ...
William Henry Pickering was another who proposed the idea of continental drift before Wegener. In
1907 Pickering suggested that moon was once part of the earth and broke away where the Pacific
Ocean now lies. He speculated that America, Asia, Africa, and Europe once formed a single
landmass that eventually broke up because of the separation of the moon. Alfred Wegener was a
German polar researcher, geophysicist, and meteorologist. During his lifetime he was mainly known
for his achievement in meteorology, but after his death he is most remembered for his advancement
of the idea of continental drift. In 1912 he theorized that the continents were slowly drifting around
the earth. It was not until the 1950s though that his ideas were widely accepted. Numerous
discoveries at that time, such as paleomagnetism provided strong support for his idea of continental
drift. Wegener first thought of this idea by noticing that the landmasses of earth fit together like a
jigsaw puzzle. The Continental shelf of the Americas fit closely to Africa and Europe, and
Antarctica, India, Australia, and Madagascar fit next to the southern tip of Africa. Wegener closely
analyzed either side of the Atlantic Ocean for rock type, geological structure, and fossils, and
noticed a significant similarity between matching sides of the continents, specifically in plant
fossils. Alfred
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Marine Biology Lab Report
2. Temporal variability of alkaline earth metals in seawater: implication for variation in geochemical
cycling Ocean plays a key role in geochemical cycling of alkaline earth metals that are directly
connected to the global C–cycle. Hence secular variation of elemental and concentrations and
isotopic compositions of seawater can reflect major changes in the lithosphere and the atmosphere
over geologic time. Consequently, elemental and isotopic composition of marine chemical
sediments (e.g., carbonates, oxides and evaporates) have been utilized extensively as geologic
archives that potentially record secular variation of ocean chemistry. Long oceanic residence time of
metals like Ca, Mg, and Sr makes them potential to record long–term ... Show more content on
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Although, the high temperature basalt–seawater interaction in the mid oceanic ridge axis considered
to have no isotope effect on the seawater Mg, the potential of fractionating Mg isotopes during
seawater circulating through low temperature ridge flanks is still unexplored. Hydrothermal removal
of Mg in the MOR flank can vary between 10–80% of the total Mg removal via seawater–basalt
interaction and part of that Mg is incorporated into the CaCO3 precipitated to form calcium
carbonate veins (CCV). Given the abundance (1–4 vol%) of CCVs in the upper ocean–ic crust and
potential to incorporate significant amount of Mg (~10 times more than biogenic calcites) CCVs can
be another potential sink for Mg in the ocean and since carbonates are known to fractionate Mg
isotopes CCVs can regulate both concentration and isotopic composition of Mg in seawater.
Besides, due to the lack of resolvable sen–sitivity of Mg isotopic fractionation in carbonates to
temperature, the CCVs can also record variability in seawater δ26Mg. This motivates me to
investigate, the δ26Mg of CCVs from various MOR flanks to evaluate i) their role in controlling
oceanic Mg budget and ii) their potential as proxy for seawater δ26Mg. To fulfill the primary
objective of this project I plan to 1) obtain CCV samples from various ocean basins. The sample
repository of the Ocean Drilling Program
... Get more on HelpWriting.net ...

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Compare And Contrast How Magmas Are Generated At Mid-Ocean

  • 1. Compare And Contrast How Magmas Are Generated At Mid-Ocean COMPARE AND CONTRAST HOW MAGMAS ARE GENERATED AT MID–OCEAN RIDGES AND SUBDUCTION ZONES. According to Middlemost (1988)'s basic definition, magma is a heated rock–forming substance that is created within a planet and exists only below Earth. When magma escapes to the Earth's surface and is extruded, they are known as lavas. Grotzinger and Jordan (2010) suggests that magma mainly comes from the asthenosphere– the upper part of the mantle. Magmas are usually generated when rocks are under the right temperature and pressure conditions to undergo partial melting (Grotzinger and Jordan, 2010). At high temperatures and low enough pressures, rocks would reach its melting point easily. It is known for a fact that temperature increases with depth ... Show more content on Helpwriting.net ... Subduction zone magmas are formed by convergent plate boundaries between oceanic–continental plates or oceanic–oceanic plates (at least one tectonic plate has to be oceanic) (see Fig.1). According to Grotzinger and Jordan (2010), when the oceanic lithosphere gets subducted, there is fluid induced melting occurring to the mantle wedge. Therefore, this generates magmas of varying composition. From Prichard et al.'s findings, mid–ocean ridge magmas are usually basaltic in composition whereas subduction zone magmas are andesitic and more silicic. Subduction zone magma compositions also depend on the materials being subducted. Hence, in terms of chemical composition, the subduction zone magmas and are definitely more varied compared to the mid– ocean ridge magmas. Subduction zone magmas range from basaltic to rhyolitic– with andesitic magmas being the most common (Grotzinger and Jordan, 2010). Fig.2 Geothermal gradient varying in different geological settings: also showing the solidus for MOR and subduction zone mantle rock MAGMA GENESIS Middlemost (1988) states that in the mantle at depths between 60–250 km (i.e. the low–velocity zone), magma can be generated through either of the 3 ways; when you add ... Get more on HelpWriting.net ...
  • 2.
  • 3. Plate Tectonics: Birth Of A Theory Based on the information in the textbook and the instructor note, plate tectonics is the Earth's surface divided into several plates that move slowly and change in size. I found the video Plate Tectonics: "Birth of a Theory" in session 13 very useful. It helps me understand the material easily by using the animation to illustrate the process of plate tectonics. It is amazing about the fact that the continents can be made to fit together like pieces of a picture puzzle. About 225 million years ago, the Earth seemed to contain only one piece of continent. However, as time goes by, the plate boundaries have happened. The plates that move away from one another are called divergent plate boundaries. The plates that move toward each other are called ... Get more on HelpWriting.net ...
  • 4.
  • 5. SMT 312 Natural Disasters Vitasta Vyas Professor Cummings SMT 312 Natural Disasters January 31, 2018 Ring of Fire An arc which spreads from New Zealand all the way to the west coast of North and South America where three–quarters of world's volcanoes are found is called the Ring of Fire. According to the scientists in the video plate tectonics play a very important role in forming of all the volcanoes. The Ring of Fire is also famous for the earthquakes which takes place here. Ninety percent of the world's earthquakes occur around the Pacific Rim, which is also an aftermath of shifting of plates. The process that moves the rocks and the seawater into the Earth is called subduction. The scientists explained the process of subduction through a 3D picture of the ... Get more on HelpWriting.net ...
  • 6.
  • 7. Oceanography Personal Statement The ocean has always been of interest to me. Growing up in New Jersey, I have had the privilege to go to the beach all throughout the year. This allowed me to see how the beach would change throughout the seasons, making me aware that this was a dynamic environment. My family also enjoyed going on vacations down south, which exposed me to different types of beaches. The differences of the types of beaches always fascinated me, especially the sand. I wanted to learn why the sands changed depending on where we were, and what composed the sand. As I have gotten older, this curiosity of the different sands on the beaches has evolved, but I never thought of marine sciences as a career choice until high school. I was never exposed to any formal education surrounding marine science, besides the couple of lessons on marine animals during science classes in grade school. It was not until junior year when I was placed in a class specifically related to marine science that I discovered that I could take my curiosity of the ocean and explore it as a career. I am currently a sophomore at Stockton University studying oceanography and geology. I am particularly interested in tectonics and mid–ocean ridges. I think it is extremely important to study these ridge systems, as they ... Show more content on Helpwriting.net ... I have the desire to learn as much as I can about geology and oceanography, and I believe earning my doctorate is a great way in which to do this. After the completion of my doctorate, I would like to go into research, specifically concerning mid–ocean ridges and plate tectonics. I hope that my contributions will be able to help myself and other understand the processes that affect the Earth more. Eventually, I would like to become a professor. I owe most of my interest in the marine sciences due to the enthusiasm of my marine science teacher in high school, so I would like to inspire students to pursue careers in the marine ... Get more on HelpWriting.net ...
  • 8.
  • 9. Submarine Volcanoes : The Most Important Type Of Submarine SUBMARINE VOLCANOES Sub marine volcanoes are fissures or vents present under water, through which magma comes out. These submarine volcanoes are one of the principal dynamic forces acting on earth's crust. The volcanic eruptions which take place under the surface of water at mid oceanic ridges, subduction zones and within tectonic plates due to hotspots add up to produce submarine volcanoes. Sub marine volcanoes are far mare superior to sub aerial volcanoes in terms of magma generation. According to an estimate about 75% of total magma is formed at oceanic ridges. The major fraction of these submarine volcanoes are deep seated in nature with some exceptions of near shore volcanoes. TECTONIC ENVIRONMENT OF SUBMARINE VOLCANISM:– The eruptive nature of submarine volcanoes cannot be confirmed as these volcanoes are deep under water. Some volcanologists believe explosive eruption is not possible due to high pressure created by surrounding water. Submarine volcanism takes place in different tectonic settings such as mid oceanic ridges, hotspots, subduction zones and hydrothermal vents. Mid oceanic ridges are the most important type of submarine eruption giving rise to mid oceanic ridge basalt or MORB. MORB covers about half of Earth's surface, though in most places they are overlain by a thin layer of deep marine sediments. The mid oceanic ridges are dominated by silent, gentle effusive volcanic activity and generate remarkable quantity of lava sheets. Oceanic plateaus are also ... Get more on HelpWriting.net ...
  • 10.
  • 11. How Plate Tectonics Discovered In this essay I will be telling you about plate tectonics. In my first paragraph, I will be talking about how plate tectonics were discovered. Plate tectonics is theory that earth's outer shell divided into severally. The mantle plates that glide over the mantle is the rocky inner layer above the core. The plates act like a hard and rigid shell compared to earth's mantle.The strong outer layer is called litosphere. Developed from 1950's to 1970's, plate tectonics is the modern version of continental drift .This theory was first proposed by scientist Alfred Wegener in 1912. Plate tectonics is the unifying theory of geology that explains the structure of the earth's crust. The earth's surface is broken into many different sections called plates. ... Get more on HelpWriting.net ...
  • 12.
  • 13. Eight Thousanders Research Paper 3. The "Eight–thousanders" are the 14 highest peaks in the world. These are the only mountains on Earth which are at peaks of death zones. Death zones are areas where there is an insufficient amount of oxygen available. These mountains are located on the Himalayan and Karakoram ranges in the countries: China, India, Nepal and Pakistan (all in Asia). They are the only mountains to exceed 8,000 m above sea level. This height and the number of highest peaks drives climbers to an obsession of climbing all of the mountains in a lifetime. These high peaks in the Himalayas are mainly Fold Mountains which formed when two plates collided head on and the sides had pieces breaking off. The two plates which collided were Asia and India, which formed these mountains. The eight–thousanders are important globally because they help geologists figure out the story of how processes have created mountains and their shape on the Earth. This story is of the 14 mountains began 40 million years ago when the subcontinent of India cam into a collision with Asia, the edges of the collision created the rifts and valleys of the ranges. This is major for geologists as well as they aid a lot in telling the physical processes of how mountains ... Show more content on Helpwriting.net ... This Mid Atlantic Ridge was discovered in the 1950s and is very important to the globe because the discovery of the ridge led to the theory of seafloor spreading. Seafloor spreading is where new ocean lithosphere gets created through eruptions and also how the basin of the ocean becomes wider. Its discovery also allowed many people to accept Wegener's theory of the continental drift. The Ridge separates the North American Plate form the Eurasian Plate in the Northern part of the ocean. In the South Atlantic, the ridge separates the South American and African Plates. These plates continue spreading, causing the Atlantic to ... Get more on HelpWriting.net ...
  • 14.
  • 15. Marine Volcanoes Vs Landforms Submarine volcanoes, mid–ocean ridges, and submarine canyons are all grouped into the marine geology systems. Underwater structures can actually be pretty useful to marine geologists, in 1930 studies found the seafloor to have all of the same physical features on land like mountains, volcanoes, canyons and more. The seafloor is estimated to be less than 2,000,000 year old, being a lot younger than landforms. The 'age' difference of the two makes marine geologists' work a lot more fun to compare in finding the way rocks are built, how the sediments are compatible and finding an estimated location of natural disasters underwater. Submarine volcanoes, also known as sea mounts, are underwater landforms that magma releases from. They're most commonly located near ocean ridges because that's where the most tectonic plate movement happens therefore, more eruptions. Depending on the depth at which the volcano is, vapor clouds may be visible but usually only in shallow waters. There are two big types of volcanic eruptions, huge lava pockets that release really slowly and and bunch of little lava pockets that burst super fast. There has been a study conducted so that scientists are able to differentiate the types of eruption so that they know ... Show more content on Helpwriting.net ... There are close to as many, or possibly equal amount of landforms as there are on the seafloor that are just as important. In fact, there's an estimated 20 eruptions that happen annually through submarine volcanoes and 80% of volcanoes are found under the ocean. One of the biggest mountain ranges is the mid–oceanic ridge system, it connects in some way to every single ocean in the world and is bigger than any other on land mountain range. Lastly, submarine canyons have opened up this huge area of research that helps so much with oil discoveries and such. The seafloor is no less than land and in most cases, the seabed is more useful to our research than landforms ... Get more on HelpWriting.net ...
  • 16.
  • 17. Mount St Helen Research Paper Mount Saint Helen The theory of the continental drift is that the continents have slowly drifted to their current location. Alfred Wegener believed that all the seven continents were once a supercontinent known as Pangea. A discovery that came from climate clues like glacial deposits in South America, Africa, Australia and India. Rock and fossils matching evidence found in South America and Africa. The theory of plate tectonics states that Earth's outer shell is divided into plates. The crust and upper mantle is broken into plates that move around on the mantle, changing in size throughout time. The lithosphere makes up the crust and upper mantle and the asthenosphere a plastic like layer beneath the lithosphere. There are three types of plate boundaries. Divergent boundaries where two plates move away from each other. The ocean widens and new crust forms at the mid–oceanic ridge. Convergent boundaries has three types of converging, moving two plates towards each other. First we have an ocean floor plate that collides with a less dense continental plate. Next an ocean floor plate collides with another ocean floor plate. Finally a continental plate collides with another continental plate. Transform boundaries were two plates slide past one another. The resulting effects of plate tectonics is landforms such as rift valleys, ... Show more content on Helpwriting.net ... Mount Saint Helen is located on The Ring of Fire, a zone of active volcanoes. In 1980 Mount Saint Helen erupted due to its location on a destructive plate boundary where a continental plate (North American) meets an oceanic plate (Juan de Fuca). Since the oceanic plate is denser it will submerge under the continental plate. The plate melts because of friction between moving plates. The melted plate is now magma which rise through the gaps in the continental plate, forming a volcano once it reaches the ... Get more on HelpWriting.net ...
  • 18.
  • 19. The Theory Of Plate Tectonics Plate Tectonics The theory of plate tectonics has been explored throughout history because of similarities in coastal boundaries and other evidence found such as fossil records, geometric fit, mountain episodes, the paleoclimate observed, information about the ocean floor, ancient magnetism, distribution of volcanoes and earthquakes and heat flow from the earths core. There were early theories from Wegner's continental drift which lacked an explanation for the mechanism that drove the continents apart, to Wilson's more complete theory of the cyclical opening and closing of the ocean basins due to movement of the earth's plates. The theory explains how today 's continents were once a large supercontinent that slowly drifted to their present positions and will again form one giant continent via collision. According to the Natego film Colliding Continents, the landmasses are liable to drift back to each other through plate tectonic activity. One of the few places on Earth where one can see continents being pushed apart is in Iceland, where the mid–Atlantic ridge in shows above the surface and shows how oceanic crust is made, the ridge in Iceland is almost three miles wide–on one side you have the Eurasian plate and the other is the American plate. This rifts grows forming new rock and causes the continents further apart widening the Atlantic Ocean moving about an inch a year. The theory suggests that we go through cycles of dispersion and collision over a 100–million–year ... Get more on HelpWriting.net ...
  • 20.
  • 21. How Did Alfred Wegener Prove The Continental Drift Alfred Wegener was a German Polar Researcher, geophysicist, and a meteorologist. He was born in November of 1880, and later died in November of 1930. His theory for the continental drift was that the continents had once been joined, called Pangea, and later drifted apart to form seven continents. Alfred Wegener had to gather a lot of information to prove his theory correct. The first supporting evidence Alfred found was how the continents were once connected. He was not the only one to see this, but the one to actually prove this right. He first saw that Africa and South America could connect, then he saw that all seven could do the same. He provided evidence with showing, how animal, and plants were the same but on different continents. ... Show more content on Helpwriting.net ... For an example, there was once animals called, Cynognathus and Lystrosaurus. They were reptiles that lived on land. Both of these animals were unable to swim at all, but their fossils have been found across South America, Africa, India, and Antarctica.There was some fossils that supported the theory of the continental drift. Some fossils were once connected, but then got separated with the land they were on. Still, there was not enough evidence to support that Pangea once existed. To conclude, Alfred Wegener was not going to give up on his theory of the Continental drift. The last supporting evidence to Wegener's theory is rocks. Just like the fossils, there were rocks that were once together, and they are now separated. Wengener didn't think this was a coincidence, he knew that there was such a thing as the continental drift. To back this up, he found rocks that were the same age, and type. He also connected mountain ranges to form one big mountain range. For an example, he compared the Appalachian Mountains to mountain ranges in the Eastern Greenland, Ireland, Great Britain, and ... Get more on HelpWriting.net ...
  • 22.
  • 23. Volcanic and Seismic Events as Proof of Plate Tectonic Theory Volcanic and Seismic events are major pieces of evidence towards proving that plate tectonics theory is valid. A seismic event is the transient motion and release of kinetic energy caused by sudden failure of the earth's crust, usually felt as shaking or tremors in the rock mass. Seismic events range in size from barely perceptible tremors to major earthquakes. Volcanic events occur when there is a release of magma, gas and ash from the Earth's crust. The entire outer surface of the planet is divided into these plate formations with approximately 30 in total. These different plates vary in size from over 100,000,000 square miles, for example The Pacific Plate, to the Galapagos micro plate at 12,000 square miles. Fault lines separate each ... Show more content on Helpwriting.net ... New Basaltic magma rises to the surface, cools and pushes the plates apart. The convection currents also help drag the plates apart and then pull them down at convergent boundaries. This can be seen at the mid–ocean ridges. Eruptions are non–violent with the exceptions of the East African Rift Valley where the recent eruption in 2002 in the Republic of Congo had a devastating effect on the local population, and where the ocean ridges rise up out of the sea such as in Iceland. The theory of plate tectonics also explains the formation of destructive plate boundaries which account for creating 80% of the world's active volcanoes. The melting crust at Subduction Zones (oceanic–oceanic or continental–oceanic) are due to differences in density between oceanic and continental lithospheres, where the less dense plate is pushed beneath the more dense plate, and becomes part of the asthenosphere forming magma that is andesitic in its nature. This creates the most violent volcanic activity. Island Arc volcanoes such as Pinatubo and Fold Mountain Volcanoes such as Nevado Del Ruiz (Andes) are very destructive. The evidence for deep, hot, convective currents combined with plate movement (and concurrent continental drift) also explained the mid–plate "hot spot" formation of volcanic island chains for example the Hawaiian Islands and the formation of rift valleys such as The Rift Valley of Africa. Mid–plate earthquakes, such as the powerful New Madrid ... Get more on HelpWriting.net ...
  • 24.
  • 25. Axial Seamount Research Paper The Axial Seamount is a very interesting landform. The Axial Seamount is an active volcano. Most people might think volcanoes would be above ground however, this volcano is actually underwater. The Axial Seamount was the site of the very first underwater volcano observatory. It is 300 miles from the coast of Oregon and is 1400 miles deep. The Axial Seamount is an underwater volcano. In the Northeast Pacific, it is actually the most active underwater volcano. The volcano is on top of a divergent plate boundary. This volcano is on the Juan De Fuca ridge and the Pacific Plate. This volcano is one of the best–studied volcanoes along the global mid–ocean ridge (Interactive Oceans). In 2011, Axial Seamount erupted. In 2006, Bill Chadwick who is a ... Show more content on Helpwriting.net ... Some landforms around the Axial Seamount art the Juan De Fuca ridge and plate, the Pacific Plate, mid ocean ridges, subduction zones, and a caldera . A caldera is volcanic crater that is very big. They can be made from two things, a very big volcanic eruption or rocks from the surface entering an empty magma chamber. The Axial Seamount has a caldera at its summit. I thought that the Axial Seamount was very interesting. One fact that I learned is that researchers found out about the 2011 eruption by accident. The thought of finding something like that out is funny. Another thing I found interesting is that if a ship was going over the seamount and it erupted, no one on the ship would probably happen. I think it is crazy to have something big like that happening under you, and you would have no idea it was happening. Learning about the seamount was an interesting experience. The Axial Seamount is an active volcano. It is on the Juan De Fuca and Pacific plate. The Seamount erupted in 2011 and was found out about by accident. There are many landforms around the Seamount, one being a caldera. I thought the Axial Seamount was very interesting and wish to study it more in ... Get more on HelpWriting.net ...
  • 26.
  • 27. Wegener's Fossils The boat was being tossed upon the sea. The sails were torn from the harsh and unforgiving wind; the cast about to snap in two. Alfred Wegener was observing his map to see if he was lost. All of the sudden, something clicked. His eyes jotted back and forth on the paper as he discovered that the continents all fit together like pieces of a puzzle. Could the continents have once been connected? Wegener introduced his hypothesis to other scientists, but they rejected this proposal after no logical explanation as to how the continents moved was provided. In circa 1960, another scientist, J. Tuzo Wilson, decided to reintroduce Wegener's hypothesis. Scientist took interest this time around because Wilson, and other scientists including Harry Hess, turned Wegener's hypothesis into a scientific theory that explains that the continents moved, how they moved, and that they are still moving today. A few crucial pieces of evidence that the continents moved are Wegener's observations. Although scientists disregarded his studies, he did have pieces of substantial evidence that the continents had moved. First is his evidence from fossils. Fossils are important because they give traces of ancient organisms. If Wegener wanted to prove that the continents moved, fossils would have to be included in his analysis. For example, the Lystrosaurus and Mesosaurus ... Show more content on Helpwriting.net ... Scientists were able to uncover the answer to this question through sea–floor spreading, or more accurately, evidence from molten material, magnetic stripes, and drilling samples. It all starts at the mid–ocean ridge, the longest chain of underwater mountains in the world. During the process of sea–floor spreading, molten material rises from the mantle and erupts at the mid–ocean ridge. The hot material spreads out, pushing away the cool, older, hardened material to both sides of the ridge, ultimately expanding the ocean ... Get more on HelpWriting.net ...
  • 28.
  • 29. Chile 1960 Research Paper In Valdivia, Chile 1960 an earthquake changed the lives of many. An earthquake is the violent shaking of the ground that will destroy homes, buildings, landforms, historical monuments, and lives. Earthquakes begin with the breakage of rock along a fault line. When two tectonic plates rub against each other they create an earthquake. Earthquakes will ride along a fault line which will determine how long the quake will go on. The larger and longer the fault like the bigger the earthquake. Earthquakes send out waves, primary waves or, p waves and secondary waves or, s waves travel along the interior of the earth. These two waves are called body waves. While detecting the waves, the primary waves appear first then the secondary waves. Primary waves travel through solids, liquids, and gasses, which means they are about to travel through the liquid center. Secondary waves are only able to travel through solids which are why scientists have found that there is a loss of these waves once they reach the center. ... Show more content on Helpwriting.net ... Before the quake hit the day before, there were a series of shocks that tipped off to people of Chile that something was coming. The day that the earthquake hit, it was a rated a 9.5 on the Richter Scale. The intensity of this caused thousands of buildings to be destroyed and 2,000,000 people left homeless. The population of the city had greatly decreased and the city also needed to pay for the damage to be repaired. It would be 800 million American dollars to complete the cleanup and repairs of the city almost completely. This earthquake was called "The Great Chilean Earthquake" because of the total destruction and because of the expansion of it where other countries received the aftershocks and effects. Japan had received a tsunami a day later, killing 138 people and leaving 1600 homes destroyed. Japan was left to pay 34 million dollars for damage ... Get more on HelpWriting.net ...
  • 30.
  • 31. Plate Tectonics Research Paper Have you ever wondered why our continents are in the positions that they are in today? Plate Tectonics can be used to explain the movement of the plates and the landforms they make. These landforms include mountains, volcanoes, rift valleys, and much more that are made by convergent and divergent boundaries. The plates are moved by the convection currents below the surface which is caused by a heat source, the mantle. Another landform that is made is a mid–ocean ridge, at which sea floor spreading is taken place, and allows magma to rise and harden on the ocean floor. Two different types of landforms that form at convergent boundaries are mountains and volcanoes. Mountains, such as Mount Everest and K2, are formed when two continental plates collide, which causes the landforms to rise. Volcanoes, such as Mount Saint Helens and Mount Fuji, forms when the more dense oceanic plate subducts under the less dense continental plate and is driven down into the hot asthenosphere. Subducted plate melts due to extreme heat and friction. Melted plate rises up through the crust, where it reaches the surface and cools. Those weak spots allow the magma to come out, forming into lava. There are also volcanic island arcs, which form when two oceanic plates collide, and continental volcanic arcs, which forms when an ... Show more content on Helpwriting.net ... Mid–Ocean Ridges, such as the Mid–Atlantic Ridge, are formed when two oceanic plates move away from each other, allowing magma to rise up from inside the Earth. The magma reaches the bottom of the ocean, turns into lava and cools, forming new rock. This cycle continues constantly spreading the sea floor and adding new material along this chain of mountains. Rift Valleys, such as Baikal Rift Valley, are formed when two continental plates move away from each other, stretching out the crust, until it begins to break. As crust is stretched wider, the valley drops ... Get more on HelpWriting.net ...
  • 32.
  • 33. Volcanic and Seismic Events Are Major Pieces of Evidence... Volcanic and Seismic events are major pieces of evidence towards proving that plate tectonics theory is valid (40 marks) The theory of plate tectonics states that the Earth's lithosphere (top layer of the Earth's crust) is split up into rigid sections called plates that are moving relative to one another as they move on top of the underlying semi–molten mantle. These plates are either continental, The North American Plate, or oceanic, The Nazca Plate. Tectonic plates are powered by convection currents, which is the circular movement of magma within the mantle. These currents are powered by the core, which heats the magma, causing it to rise, cool and fall back down. This circular motion causes the plates, which float on the mantle, to ... Show more content on Helpwriting.net ... Earthquakes can be created on any of the plate boundaries. Earthquakes occur when tension is released from inside the crust. Plates do not always move smoothly alongside each other and sometimes get stuck. When this happens pressure builds up. When this pressure is eventually released, an earthquake tends to occur. The point inside the crust where the pressure is released is called the focus. The point on the Earth's surface above the focus is called the epicentre. Earthquake energy is released in seismic waves. These waves spread out from the focus. The waves are felt most strongly at the epicentre, becoming less strong as they travel further away. The most severe damage caused by an earthquake will happen close to the epicentre. But there are some anomalies as there are earthquakes which don't take place on a plate boundary and it's the same with volcanoes. An example of this is Hawaii. Hawaii is a volcanic island which is found in the middle of a tectonic plate. Hawaii is an example of a hotspot. The places known as hotspots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. They may be on, near to, or far from tectonic plate boundaries. There are two hypotheses to explain them. One suggests that they are due to hot mantle plumes that rise from the core–mantle boundary. The other hypothesis postulates that it is not high ... Get more on HelpWriting.net ...
  • 34.
  • 35. The Theory Of Plate Tectonics Plate tectonics is the theory that the Earth's crust is divided into large and small plates that move slowly over time. The Earth's lithosphere is made up eight major plates which include the Africa Plate, Antarctic Plate, Indo–Australian Plate, Australian Plate, Eurasian Plate, North American Plate, South American Plate, and the Pacific Plate. Earth also has dozens of smaller, minor plates (Plate Boundaries). Scientists used this theory to explain what is happening on Earth's surface. The movement of plate tectonics creates many plate boundaries that have formed landscape features we see on Earth today such as volcanoes and mountains among many other features. The theory of plate tectonics helped geologists to apprehend how the continents are in the position that they are today as well as how landscape features are created. The theory of continental drift is that all of the world's continents were once a single continent called Pangaea, which slowly drifted apart over time forming the seven continents that we have today. This theory was proposed by Alfred Wegener, a German Meteorologist, in 1912. Wegener gathered several pieces of evidence that supported his theory of continental drift. Wegener's first piece of evidence was that the shape of Earth's continents seem to fit together like a jigsaw puzzle. For example, Africa's West Coast nearly fit with South America's East Coast. A second piece of evidence that supported Wegener's theory are glacial till deposits ... Get more on HelpWriting.net ...
  • 36.
  • 37. GEPlateTectonicsAnswers Adapted from an activity by Laurel Goodell February 2013 Introduction to Plate Tectonics via Google Earth (24 pts) B. Topographic Patterns Uncheck all of the layers and focus on topographic features of the earth. Topography of the earth ABOVE sea level Questions Answers 1. Are mountains randomly distributed on the continents, or do they tend to occur in particular patterns (clusters, linear chains, arcs, etc.)? Some appear in lines and others in arcs 1pt 2. Find Mt. Everest, the highest point on earth. Zoom in enough to see the summit, then pan your cursor around to locate the 8840_______ meters highest point (elevations shows up in the status bar at the bottom, as long as View/Status Bar is selected): 1pt Adapted from an activity ... Show more content on Helpwriting.net ... Be sure to consider topography/bathymetry as well as the earthquake and volcano layers. List several ways and be specific. 3pts In the middle between the two Without the plate boundary feature, you would still see the change in depth where the mountains are, still feel earthquakes, and see volcanic eruptions.
  • 38. Adapted from an activity by Laurel Goodell February 2013 Mid–Atlantic Ridge F. Plate motion Motion across the mid–Atlantic ridge: the South American plate vs. the ... Get more on HelpWriting.net ...
  • 39.
  • 40. Chapter 2 STUDY GUIDE: Chaps. 2 GEOL 111G–Survey of Geology At the end of each chapter are Review Questions and Key Terms. To study for the final, be sure to know the answers (or where to find the answers) for the given review question numbers and know the definitions of the key terms indicated. The Key Terms have page numbers for reference in the textbook. CHAPTER 2 Review Questions: #'s are based upon the 10th edition. These may be different in older or newer editions. 2. What was the first line of evidence that led early investigators to suspect that the continents were once connected? The puzzle–like fit of the continents, especially Africa and South America. 3. What was Pangaea? Pangaea, the supercontinent named by Alfred Wegener, is ... Show more content on Helpwriting.net ... However, if you travel away from the ridges you will encounter rocks with reverse polarity and then rocks of normal polarity which are followed by reverse polarity rocks, etc. Vine and Matthews observed that there were symmetrical bands of rocks with similar polarities on each side of every mid–ocean ridge. They hypothesized that the reverse polarized rocks formed at the ridges during the geologic past when the earth's magnetic field had reverse polarization. Their work provided rather elegant proof that the seafloor spreading actually occurs. 11. Compare and contrast the lithosphere and the asthenosphere. –Both in the mantle. –Lithosphere is Earth's crust and at 100–150 km of the mantle. –Asthenosphere is in the upper mantle. –Lithosphere is relatively rigid while asthenosphere has low rigidity. –Asthenosphere acts as a lubricant. –Plates in the lithosphere move because of asthenosphere. 12. List the three types of plate boundaries and describe the relative motion at each of them. Divergent boundaries–where plates are moving apart Convergent boundaries–where plates are moving together Transform boundaries–where plates slide past one another along faults 13. Where does new lithosphere form? Where is it consumed? Why does the rate at which new lithosphere forms roughly balance the rate at which lithosphere is destroyed. Elevated position of the oceanic ridge, increase in ocean depths away from ... Get more on HelpWriting.net ...
  • 41.
  • 42. Memorable Experience The Memorable Experience When I was teenage life ,my special someone say I have my entire life ahead of me, with all of its best experiences I had. But despite being a teenager, I already have a personal breath taking experience, for hike and the mountain which I am sure I will carry with me until my last days my first hike to the mountains traveling is not a big deal for me today, before my trip to the mountains, I used to be a homebody. I had special someone to hang out with, several hobbies, and I feel completely comfortable spending weeks or even months in my hometown sometimes even on my block without going anywhere. All my demands of novelty were satisfied by the Discovery the wild life and the mountain, and I seriously thought ... Show more content on Helpwriting.net ... The same fog was covering the surroundings, and even though I was teeming with positive emotions, I feel disappointed, because I counted on seeing the view from above and perhaps being able to take some photos. We spent a couple of hours on the top, and decided to turn back, when the wind suddenly dispersed the clouds, and the plateau we were standing on became illuminated with the sun. I saw a fantastic skies and clouds in front of me, and for some moments I couldn't believe my eyes. Seeing all those mountain ridges, cliffs, and edges on my own eyes, not on TELEVESION, INTERNET was like a revelation for me. The strong wind blew right into my face, and I just stood there and watched shreds of fog gliding over the ground far beneath me. At that moments, that I can realized that I won't be able to lives a life without visiting and seeing the beautiful mountains at least One a year or twice a year and I told Joana, to stay for few hours and watched the sunset before waiting the sunset When I saw Joana how excited and I suggested where going have a picnic and I get the foods and drinks When we finished eating ,before we leave can 't be walk around and I said to Joana how great of a time I had with him after ... Get more on HelpWriting.net ...
  • 43.
  • 44. The Theory Of Plate Tectonics And Earth 's Crust Displacement For millions of years the Earth has experienced geologic catastrophes. Since the existence of Theia itself, the Earth's crust has been formed, deformed, and even demolished. The crust has never been a completed masterpiece due to this. Why is this? The most recent physical changes were caused by the theory of plate tectonics and earth's crust displacement. Plate tectonics and its movement resulted in our continents drifting across the earth's surface, and the creation of mountain belts, volcanoes, and the faults of today's Earth. A German meteorologist and explorer Alfred Wegener put forth the theory of continental drift in the early 1900's. Wegener pointed out that the earth's continents looked as if they were all connected at one point in time. He also pointed out that some of earth's features, including the long S–shaped mountain structure formed on the Atlantic seafloor, could fit snugly against the corresponding western seafloor of Europe and Africa (Sieh and LeVay 1998). Wegener proposed that all of the earth's continents once formed one single landmass, which he named Pangaea or "all–land". He concluded that Pangaea had broken up and separated due to the unidentifiable forces estimated 300 million years ago (Sieh and LeVay 1998). Geologists did not fully understand at the time that Earth's continents could drift (Hazen 2012). After all, the continents do not float in the oceans. They are made from a solid material connecting to the mantle, a sphere of solid rock ... Get more on HelpWriting.net ...
  • 45.
  • 46. Types And Regional Distribution And Frequency Of... i. Abstract Numerous extinct spreading centres are found within the world's ocean basins and these record instances of spreading cessation or migration that provide valuable insights into the mechanism of heat–loss from the mantle and plate tectonic behaviour. This study presents the first comprehensive review of all reported extinct ridges and investigates their characteristics and regional distribution and frequency of occurrence over the last ~170 Myr as recorded in present–day preserved oceanic crust. The axial morphology, gravity signal and crustal structure of extinct ridges are evaluated by generating across–axis profiles through global datasets (IHO – IOC 2014; Sandwell et al. 2014) for individual ridge segments. Information on the spreading–rates, time of cessation and duration of spreading prior to cessation was collating information from previous studies. The potential geodynamic influences on the lifespan and activity of mid–ocean ridges were investigated by evaluating the relationship of extinct ridges to hotspots at their time of extinction using GPlates (Boyden et al. 2011) and a global reconstruction (Seton et al. 2012). Global examples are investigated to assess similarities or differences and to determine the 'characteristic' signal of extinct ridges. Ridges were classified according to the quality of constraints into a primary, secondary or tertiary tier that dictated their inclusion in the quantitative analysis undertaken. Spreading centre subtype is ... Get more on HelpWriting.net ...
  • 47.
  • 48. The theory of sea- floor spreading was introduced by Herny... The theory of sea– floor spreading was introduced by Herny Hess in 1960s. Hess came with the idea that new oceanic floor formed at the mid oceanic ridges. Ridges is a crack in the earth's crust through which spreads rock rises to the surface. The Melton rock spreads out and adds new material to the ocean floor. The new materials are carried away from the mid oceanic ridges. Sea floor spreading explains the existence of pillow lava near the ridges and the absence of thick layers of sediments on the ocean floor. In fact, near the ridges, sediment is not found. One of the most important contributions of the theory of sea– floor spreading was that it could explain how continent moved. (Silver Burdelt & Ginn 301–302) Sea– floor ... Show more content on Helpwriting.net ... If the sea floor spreading is not taking place all rocks found in the oceanic crust they must have same age and structure. Therefore due to the sea– floor spreading made variation of rock from the middle part of oceanic ridge to the part found far away it Formation of new oceanic crust at the mid– oceanic ridge; this also proves the theory of sea– floor spreading at the mid– oceanic ridge. The oldest one must move away from mid oceanic ridge to allow upwelling of molten materials. Molten materials later cool and solidify to form new oceanic crust. At the spreading centre liquid rock called basalt magma rises from the Earth's mante as it up wells beneath the spreading axis. When the magma hardness it forms crust that becomes welded to the original crust ( Encyclopedia Geology and Oceanograph Accumulation of sediments / Fossil as we look at these deposits– burned fossils and sediments, we will see older and older fossils as we move further and further from the mid– oceanic ridge as the results we will see greatest proportion of extinct species. Also sediments much deposit on the older part of the sea floor for longer than new parts around the mid oceanic ridge. Different sediments tend to accumulate on different parts of oceanic floor if the ocean floor stayed still then the other things being equal, we would expect same deposit of the sediments from any particular place on sea –floor to be pretty much the same all the way down. Sea ... Get more on HelpWriting.net ...
  • 49.
  • 50. How Old Is The Oldest Oceanic Crust Questions: 1) How old is the oldest oceanic crust in the: Indian Ocean: 150 million years old Atlantic Ocean: 180 million years old it's typically the same age as the Pacific Ocean Pacific Ocean: 180 million years 2) How old is the oceanic crust that is found along the coastline of Northern California? The oceanic crust found along the coastline of Northern California is about 30 million years old. 3) In the Pacific Ocean, where is the oldest oceanic crust located (generally)? The oldest oceanic crust is located along the continental margin, Which is composed mainly of the continental shelf, continental slope and continental rise. 4) In the Pacific Ocean, where is the youngest oceanic crust located? The youngest oceanic crust is located along the mid–ocean ridges where new crust is formed when the old crust is pushed away from mid – ocean ridges as a result of the seafloor spreading. 5) In general terms, describe the distribution of youngest and oldest crust in the Atlantic Ocean Basin. The color red represents the youngest crust in the Atlantic Ocean. The youngest crust is formed when two or more plates diverge in the mid–ocean ridges. The color blue, green and yellow are older crusts that are pushed away from the mid–ocean ridges when the youngest crust is formed, which is referred to as the sea floor spreading. 6) Look the Pacific Ocean Basin and compare it to the Atlantic. Specifically look at the oldest / youngest oceanic crust ... Get more on HelpWriting.net ...
  • 51.
  • 52. Mid-Atlantic Ridge Vs Volcanic Trench from each other as magma pushes up in the rift valley. The Mid–Atlantic Ridge is just a small portion of the mid–ocean ridge which encircles the Earth. Another boundary is called a convergent boundary. When the crust expands at the divergent boundary the plate is pushed into another plate where it is either sub–ducted or it buckles. This really depends on the type of lithosphere that is involved in the convergence (Kious). This convergence can occur between two ocean plates, two continental plates or an ocean and continental plates. Two of the features that can be found at a convergence boundary is a volcanic arc and a deep ocean trench. The Volcanic trench can be found over the subduction zone (Trujillo, pg 55). When an oceanic plate ... Get more on HelpWriting.net ...
  • 53.
  • 54. Proving Pangaea Existence Proven Pangaea Existence Proven Have you ever heard of Pangaea? Do you think it is real? Do you need someone to prove it for you? Well,I am here to prove Pangaea's existence to you. To begin with, you need to know what Pangaea is. Pangaea was thought of in the year of 1912. This theory was called Continental Drift and was proposed by Alfred Wegener.Pangaea was thought to be a Super Continent. When Alfred Wegener proposed this theory no one really believed him because he did not have much proof. This proof brings me into my topic "Pangaea Existence Proven". To start off with fossils that were from, for example,Europe were found in, for example, North America. This is a good reason because i do not think ... Get more on HelpWriting.net ...
  • 55.
  • 56. Theories Of Plate Tectonics Plate Tectonics have been recently discovered. Earthquakes and volcanoes can now be located and the public can find out when it will erupt or occur. Our earth has a fragile shell, which moves around recycling itself, to form new layers of crust.The theory of plate tectonics was helped develop by the theory of plate tectonics. Convection currents and gravitational forces move tectonic plates. The contact between plates, creates earthquakes, volcanoes, islands and mid ocean ridges. Mountain ranges, are examples of converging plates and modern technology can help scientists locate tumours or movement in the Earth.–Thesis–Convection currents and Plate tectonics explains global anomalies and phenomenon like earthquakes, volcanoes, mid ocean ridges ... Show more content on Helpwriting.net ... This then send out a massive wave of energy through solid rock and water. This then results to the ground and water shaking, as the massive wave of energy passes through. The ring of fire is where 90% of all recorded earthquakes have occurred. Most earthquakes form near the plate boundaries. The most strongest earthquakes have been near converging boundaries. The location of the different earthquakes can help explain and give further information for the theory of plate tectonics and where the boundaries for different plates ... Get more on HelpWriting.net ...
  • 57.
  • 58. Seafloor Spread Research Paper Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener's ideas by using the evidence of seafloor spreading to explain what moved continents. The theory of plate tectonics is what brings together continental drift and seafloor spreading. Plates are made of lithosphere topped with oceanic and/or continental crust. The plates are moved around on Earth's surface by seafloor spreading. convection in the mantle drives seafloor spreading. Oceanic crust is created at mid–ocean ridges. The crust moves outward from the ridge over time. The crust may eventually sink into the mantle and be ... Get more on HelpWriting.net ...
  • 59.
  • 60. Continental Drift One line of evidence used to support continental drift is the discovery of similar fossils on different continents. Both fossil plants and animals found in India, South Africa, Australia, Antarctica, and South America are very similar. This supports the idea that the continents were once one because it suggests that the animals roamed the land, were fossilized where they were when they died, and then we discovered the fossils after the supercontinent had separated. Another line of evidence that supports the drifting of continents is geological similarities between western Africa and eastern South America. Mountain ranges in Buenos Aires, Argentina and mountain ranges in western Africa are similar. There are also mountain ranges that extend ... Get more on HelpWriting.net ...
  • 61.
  • 62. The Spreading Of Iceland All Occurs On The Mid Atlantic Ridge The seafloor spreading in Iceland all occurs on the mid–Atlantic ridge. Iceland emerged as a result of the divergent spreading and the boundary between the two tectonic plates and the activity of Iceland's own hotspot or mantle flume. Movement of these plates caused earthquakes and volcanism. This allowed Iceland to be the largest portion of the mid– ocean ridge system that is above sea level. The beginning of the start of sea floor spreading in Iceland occurred about sixty million years ago when the North–Atlantic Ocean began to open. At this time, the North American plate along with the Eurasian plate moved east and westward at approximately one centimeter per year in each direction. This has created new basalt, and ninety–two percent of Iceland's surface area is made up of basalt. The Mid–Atlantic Ridge contains a series of spreading centers showing the ridge crest, offset in numerous areas located near transform faults that illustrate the seismically active parts of fracture zones. The dating of spreading has been recorded by magnetic lineaments, with magnetic observations from the ocean floor south of Iceland being taken advantage of in the early understanding of the ideas of plate tectonics. The largest offset is the Charlie–Gibbs Fracture Zone in the south of Iceland, where it is offset at three–hundred and fifty kilometers. To the north of this area is where the ridge is relatively straight and the depth of the water decreases at a constant rate towards Iceland. At ... Get more on HelpWriting.net ...
  • 63.
  • 64. Mid Ocean Ridges Research Paper Welcome to one of the planets most obscure but important features, known rather prosaically as the mid ocean ridges. In 1973 a group of oceanographers discovered this ridge of mountains on the ocean's floor. Since then, they have been more closely exploring the ridges and studying how they move and exactly what they are. They have come to discover, that the "ridges feature long rift valleys and, down their middles, giant fields of gushing, hot springs that shed tons of minerals into icy sea water at the bottom of the sea," which over time has come to create these huge mid–ocean ridges where many animals like to live, cause its some warm." A main question is to what extent the volcanism changes over time. The old idea was that the eruptions ... Get more on HelpWriting.net ...
  • 65.
  • 66. Interglacials Similar fluctuations in deep water formation during interglacials have been recorded in the Southern Ocean (Hayes et al. 2014). A peak in authigenic uranium was recorded in Southern Ocean sediments, at OPD site 1094, 127,000 years ago, during Marine Isotope Stage 5 (Hayes et al. 2014). At the beginning of this interglacial period, ~135,000 years ago, a sharp increase in biogenic opal flux was recorded, reflecting an increase in productivity in the Southern Ocean (Hayes et al. 2014). Oxygenation of the deep water increased with increasing Southern Ocean overturning, leading to a gradual reduction in authigenic uranium concentrations (Hayes et al. 2014). The authigenic uranium peak recorded at ~127,000 years ago, Marine Isotope Stage 5e, was ... Show more content on Helpwriting.net ... 2014). When age model uncertainties are taken into account, this δ13C decrease at ODP site 1094 is synchronous with a δ13C decrease at ODP site 1089 (Hayes et al. 2014, Galaasen et al. 2014). This highlights the bipolar seesaw at work during this interglacial period, via alternating fluctuations in both the formation of Antarctic Bottom water and North Atlantic Deep Water (Hayes et al. 2014). Summary The 'leak' in the biological pump in the Southern Ocean can be influenced by a variety of processes, changing the Southern Ocean's influence on the concentration of atmospheric CO2, and global climate over glacial–interglacial timescales (Sigman et al. 2010). Reduced ventilation in the Antarctic, as a result of decreased Antarctic Bottom Water formation, decreases the amount of CO2 released to the atmosphere and increases the storage of CO2 in the deep ocean (Sigman et al. 2010, Hayes et al. 2014, Galaasen et al. 2014). Increased sea ice coverage would have also limited the release of CO2 to the atmosphere during glacial periods (Sigman et al. 2010). Greater nutrient utilization due to increased supply of Fe either by upwelling or dust input would lead to greater rates of CO2 sequestration in the deep ocean (Sigman et al. 2010). Increased productivity in the Subantarctic Zone during glacial periods, coupled with reduced Antarctic overturning would have also increased the amount of carbon in ... Get more on HelpWriting.net ...
  • 67.
  • 68. U3A5: The Evidence Of Moving Continents SES4U4–A 10/14/2015 Mr. Ramphal Streetsville Secondary School U3A5 – Evidence of Moving Continents The Movement of Continents Introduction How do we know that continents can move across vast distances over a long enough period of time? It is very hard to imagine what amounts to 150 million kilometers squared of land that we have on the earth moving such an incredible distance. This was the main idea opposing the Continental Shift theory: there were no known forces strong enough to move entire continents against the massive force of friction, and even today many geologists are unsure whether the weaker force of the Earth's convection causes the shift, or the stronger gravity. Alfred Wegener, a German scientist, proposed that ... Show more content on Helpwriting.net ... In general, magnetic minerals such as magnetite and hematite are studied to gain more insight on our magnetic field. When the minerals are formed, their magnetism is lined up with the Earth's. This important, and many times, permanent, form of evidence can help scientists understand the history of the rock formations in question. The magnetism can not only be used to understand the past rotation of continents, but also the latitude that the rock formed at. This is due to the inclination of the specific magnetic field. The inclinations of the lines of force of the magnetic field get steeper at higher latitudes near the geographic North Pole (top of the axis of rotation of the earth), as well as the geographic South Pole. This vital fact lets scientists determine North–South motions of the past locales of the Earth's continents. An important distinction that they found between today and the past is difference in positioning between the current magnetic North Pole and the one in the past. In the present day, groupings of minerals dated to the same time period at specific continents have common magnetic field characteristics, and their fields are often not lined up with our current Magnetic North pole. The older the minerals, the more drastic difference they have between our current Magnetic North. Scientists can calculate from this that these large groups of minerals, the continents, must have moved over time so that their magnetic fields were different in the past. Also, when comparing different continents they found that the pathways were strikingly different, indicating local changes in trends. Therefore, the differing magnetic fields of minerals found within our continents can help prove the theory of Continental ... Get more on HelpWriting.net ...
  • 69.
  • 70. San Andreas Fault In California San Andreas fault in California The San Andreas fault line is one of the most notorious faults in the world where it lies approximately 1,287 km long in California, USA. Fault lines are cracks in the Earths surface, where earthquakes usually occur. The San Andreas fault in California is a transform boundary which means the tectonic plates grind against each other slowly building up tension through friction then one day they'll slip causing an earthquake to occur. Since the San Andreas fault is a transform boundary, earthquakes occur along its fault which will affect California and anywhere that the strength of the earthquake can reach making the fault a seismic hazard to those who live there. The San Andreas fault is home to thousands of ... Get more on HelpWriting.net ...
  • 71.
  • 72. Continental Drift and Plate Tectonics Continental Drift and Plate Tectonics Theory (Part 1a) Introduction: The Beginning of the "Continental Drift Theory" In the middle of the eighteenth century, James Hutton proposed a theory, uniformitarianism; "the present is the key to the past". It held that processes such as geologic forces– gradual and catastrophic–occurring in the present were the same that operated in the past. (Matt Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered that the coasts of the eastern part of South America and the ... Show more content on Helpwriting.net ... Water from the south then flowed in over time, thus forming the evaporites now found along the coastlines there. (Lois Van Wagner, 2013)(Figure 5) However, Wegener believed that only the continents were moving and they plowed through the rocks of the ocean basins. (Colliers Encyclopedia, 1996) Harold Jeffreys then argued that it is impossible for continents to break through solid rock without breaking apart. (USGS, 2012) Wegener also claimed that the centrifugal force of the spinning planet had forced the continents sideways, parallel to the equator; tidal pull from the sun and moon had caused lateral movement. (Sant, Joseph, 2012) His orders of magnitude were too weak. Thus, his theory was dismissed. (Lois Van Wagner, 2013) Further development and support of the "Continental Drift Theory" in the 1960s After World War 2, the U.S. Office of Naval Research intensified efforts in ocean–floor mapping, leading to the discovery of the Mid–Atlantic Ridge to be part of a continous system of mid–oceanic ridges on all ocean floors, prompting Harry H. Hess to suggest the theory of sea–floor spreading. The oldest fossils found in ocean sediments were only 180 million years old and little sediment were accumulated on the ocean floor. Thus, he suggested that seafloors were no more than a few hundred million years old, significantly younger than continental land due to ... Get more on HelpWriting.net ...
  • 73.
  • 74. Tectonic Plates The Earth is a very detailed planet; there are many actions going on at once on this planet. The Earth has many boundaries, plates. and layers. The plates beneath our feet mold the world we live in. While very slowly, the plates are indeed moving. There are a few variations to the plates; they have different directions in which they move in relation to separate plates. These changes in plate movement have different side effects, from ocean trenches to miles of mountain ranges. In 1912, a german climatologist, Alfred Wegener proposed that the continents were once joined and made one land mass. He named this super continent Pangaea. He had a lot of evidence to prove that they were once together, but he was missing one key section of information, ... Show more content on Helpwriting.net ... Each plate is moving a certain direction due to the convection from the Asthenosphere. The meeting of two plates is called a boundary, there are three types of boundaries in the world: Convergent Boundaries, Divergent Boundaries. And Transform Boundaries. In the case of Convergent Boundaries, two plates are pushing against each other, which can create Deep Ocean Trenches, Huge Mountains, and/or Volcanic Mountain chains. An example of this happening is the Mariana Trench, During Convergence, the denser crust, oceanic crust, is subducted below the less dense crust. If the crusts have the same density then the plates are pushed upwards. At Divergent Boundaries, the plates are moving away from each other, this can create Mid–Ocean Ridges and Rift Valleys. An example of this happening is the Mid–Atlantic Ridge. At the final boundary, Transform Boundaries, the plates slide the past one another in the opposite direction, causing shallow earthquakes and offset features. An example of this Boundary is The San Andreas Fault. While the crust moves, there are places called Hot spots in which a hot portion of the mantle rises up beneath the crust for millions of years. An example of this is the Hawaii Island ... Get more on HelpWriting.net ...
  • 75.
  • 76. The Current Shape Of Earths Landmasses Was First Proposed... Question 1 The idea of Continental Drift to explain the current shape of Earths landmasses was first proposed by Abraham Ortelius in 1596. He proposed the idea to highlight the geometrical coincidences between America and Europe–Africa. In his work Thesaurus Geographicus he suggested that the Americas were "torn away from Europe and Africa...by earthquakes and floods", and that "the vestiges of rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three." Antonio Snider–Pellegrini was a French geographer and scientist who theorized the possibility of continental drift several decades before Alfred Wegener in his publication The Creation and its Mysteries Unveiled. He came to this ... Show more content on Helpwriting.net ... William Henry Pickering was another who proposed the idea of continental drift before Wegener. In 1907 Pickering suggested that moon was once part of the earth and broke away where the Pacific Ocean now lies. He speculated that America, Asia, Africa, and Europe once formed a single landmass that eventually broke up because of the separation of the moon. Alfred Wegener was a German polar researcher, geophysicist, and meteorologist. During his lifetime he was mainly known for his achievement in meteorology, but after his death he is most remembered for his advancement of the idea of continental drift. In 1912 he theorized that the continents were slowly drifting around the earth. It was not until the 1950s though that his ideas were widely accepted. Numerous discoveries at that time, such as paleomagnetism provided strong support for his idea of continental drift. Wegener first thought of this idea by noticing that the landmasses of earth fit together like a jigsaw puzzle. The Continental shelf of the Americas fit closely to Africa and Europe, and Antarctica, India, Australia, and Madagascar fit next to the southern tip of Africa. Wegener closely analyzed either side of the Atlantic Ocean for rock type, geological structure, and fossils, and noticed a significant similarity between matching sides of the continents, specifically in plant fossils. Alfred ... Get more on HelpWriting.net ...
  • 77.
  • 78. Marine Biology Lab Report 2. Temporal variability of alkaline earth metals in seawater: implication for variation in geochemical cycling Ocean plays a key role in geochemical cycling of alkaline earth metals that are directly connected to the global C–cycle. Hence secular variation of elemental and concentrations and isotopic compositions of seawater can reflect major changes in the lithosphere and the atmosphere over geologic time. Consequently, elemental and isotopic composition of marine chemical sediments (e.g., carbonates, oxides and evaporates) have been utilized extensively as geologic archives that potentially record secular variation of ocean chemistry. Long oceanic residence time of metals like Ca, Mg, and Sr makes them potential to record long–term ... Show more content on Helpwriting.net ... Although, the high temperature basalt–seawater interaction in the mid oceanic ridge axis considered to have no isotope effect on the seawater Mg, the potential of fractionating Mg isotopes during seawater circulating through low temperature ridge flanks is still unexplored. Hydrothermal removal of Mg in the MOR flank can vary between 10–80% of the total Mg removal via seawater–basalt interaction and part of that Mg is incorporated into the CaCO3 precipitated to form calcium carbonate veins (CCV). Given the abundance (1–4 vol%) of CCVs in the upper ocean–ic crust and potential to incorporate significant amount of Mg (~10 times more than biogenic calcites) CCVs can be another potential sink for Mg in the ocean and since carbonates are known to fractionate Mg isotopes CCVs can regulate both concentration and isotopic composition of Mg in seawater. Besides, due to the lack of resolvable sen–sitivity of Mg isotopic fractionation in carbonates to temperature, the CCVs can also record variability in seawater δ26Mg. This motivates me to investigate, the δ26Mg of CCVs from various MOR flanks to evaluate i) their role in controlling oceanic Mg budget and ii) their potential as proxy for seawater δ26Mg. To fulfill the primary objective of this project I plan to 1) obtain CCV samples from various ocean basins. The sample repository of the Ocean Drilling Program ... Get more on HelpWriting.net ...