Plate tectonics is the theory that the Earth's outermost shell is divided into plates that constantly move and interact with one another. At plate boundaries, where the plates meet, seismic activity like earthquakes and volcanic eruptions occur. The three main types of plate boundaries are divergent boundaries, where plates move apart; convergent boundaries, where plates collide; and transform boundaries, where plates slide past one another. Each boundary type results in different geological features and phenomena.
introduction of plate tectonics leading to finding the epicenter.
Divergent plate boundary is alsoincluded in the ppt. Search the activity sheet on this topic also uploaded here
introduction of plate tectonics leading to finding the epicenter.
Divergent plate boundary is alsoincluded in the ppt. Search the activity sheet on this topic also uploaded here
The topic of plate tectonics is largely based on Alfred Wegner's theory of continental drift, which became accepted with the discovery of seafloor spreading in the Atlantic Ocean, and after fossil, flora, and geological studies in Africa and South America. In this lesson, students will learn about Earth’s structure, differences between various types of tectonic plate boundaries, their outcomes, and their connection to locations of volcanoes and earthquake activity.
Download the paper to access it as a word document
This is an exam style question paper (if any doubts, just comment and within days I will reply). I hope you like this. Please like and also download the pdf so you can have it as reference. Moreover, I have combined all past papers into one which is in your hands now. Please, do not hesitate if you have any doubts regarding plate boundaries/tectonic plates or even any comments to improve my work.
that is associated with broad upwarping of the overlying litho.docxmattinsonjanel
that is associated with broad upwarping of the overlying lithosphere (figure 5.1 iA). As a result, the lithosphere is stretched, causing the brittle crustal rocks to break into large slabs. As the tectonic forces continue to pull the crust apart, these crustal fragments sink, generating an elongated depression called a continental rift (figure 5.1 ib).
A modern example of an active continental rift is the East African Rift (figure s. i 2). Whether this rift will eventually result in the breakup of Africa is a topic of continued research. Nevertheless, the East African Rift is an excellent model of the initial stage in the breakup of a continent. Here, tensional forces have stretched and thinned the crust, allowing molten rock to ascend from the mantle. Evidence for recent volcanic activity includes several large volcanic mountains including Mount Kilimanjaro and Mount Kenya, the tallest peaks in Africa. Research suggests that if rifting continues, the rift valley will lengthen and deepen, eventually extending out to the margin of the landmass (r;<;ur.E 5.1 ic). At this point, the rift will become a narrow sea with an outlet to the ocean. The Red Sea, which formed when the Arabian Peninsula split from Africa, is a modern example of such a feature. Consequently, the Red Sea provides us with a view of how the Atlantic Ocean may have looked in its infancy (figure 5.1 id).
QEOD^
Forces Within sSWHBe Plate Tectonics
New lithosphere is constantly being produced at the oceanic ridges; however, our planet is not growing larger—its total surface area remains constant. A balance is maintained because older, denser portions of oceanic lithosphere descend into the mantle at a rate equal to seafloor production. This activity occurs along convergent (con = together, vergere = to move) boundaries, where two plates move toward each other and the leading edge of one is bent downward, as it slides beneath the other.
Convergent boundaries are also called subduction zones, because they are sites where lithosphere is descending (being subducted) into the mantle. Subduction occurs because the density of the descending tectonic plate is greater than the density of the underlying asthenosphere. In general, oceanic lithosphere is more dense than the asthenosphere, whereas continental lithosphere is
(
Upwarping
figure 5.11
Continental rifting and the formation of a new ocean basin.
A.
The initial stage of con tinental rifting tends to include upwelling in the mantle that is associated with broad doming of the lith-osphere.Tensional forces and buoyant uplifting of the heated lithosphere cause the crust to be broken into large slabs.
b.
A
s the crust is pulled apart, large slabs of rock sink, generating a rift valley.
C.
Further spreading generates a narrow sea, similar to the present-day Red Sea.
D.
Eventually, an expansive ocean basin and ridge system are created.
)less dense and resists subduction. As a consequence, only oceanic lithosphere will subd ...
Steps to Plate TectonicsStep 1 – Continental Driftwww.mat.docxdessiechisomjj4
Steps to Plate Tectonics:
Step 1 – Continental Drift
www.math.montana.edu / ~nmp / materials / ess / geosphere / inter / activities / plate_calc / pangaea_map.gif
The Continental Drift hypothesis published by Alfred Wegener in his 1915 book “ The Origin of Continents and Oceans”, although this was partially based on the work of earlier investigators.
Continental Drift = the continents were once connected in a single supercontinent called Pangaea. They have since drifted apart and are still moving today.
http://www.kidsgeo.com/geology-for-kids/0042-pangaea.php
Wegener’s hypothesis had several problems:
1) He had no power source – no way to make the continents move.
2) He thought the continents moved through the seafloor just like boats move through the ocean, but there was no evidence of this (no wake)
3) He was a meteorologist so many geologists didn’t take him seriously!
BUT Wegener had lots of evidence to show that the continents were once connected!
1) The jigsaw puzzle-like fit of the continents.
Figure 2.3 in text
Identical fossil assemblages on now widely spaced continents!
best about 250-200 MY ago
become increasingly dissimilar the closer to today we look!
Garrison, 2012, Essentials of Oceanography
3) Sequences of similar rock types on continents which do not now have the same geologic environment!
http://www.geology.ohio-state.edu/~vonfrese/gs100/lect25/index.html
4) Geologic structures (mountain ranges, faults, chains of volcanoes) which match up on either side of oceans but can not be found underwater.
5) Apparent polar wander – paleoclimatic evidence the continents had very different climates 250 MY ago than they do today.
either the continents moved or
the climate bands moved – which means the Earth’s poles of rotation moved.
Earth’s climate zones today are arranged symmetrically around the poles.
http://www.webquest.hawaii.edu/kahihi/sciencedictionary/C/climatezone.php
Paleoclimatic data from ˶300 MY ago, figure 2.5 in text
After Wegener died, his ideas were largely dismissed, until…
Post-Wegener evidence for drifting continents (and plate tectonics)…
6) Apparent Polar Wander – Paleomagnetic evidence.
Figure 2.7 showing that the Earth has a magnetic field very similar to that created by a bar magnet.
Directions of magnets parallel to Earth’s magnetic field lines.
Post-Wegener evidence for drifting continents (and plate tectonics)…
Figure 2.7b showing how magnets align to the Earth’s magnetic field when allowed to move freely.
Rocks containing the mineral magnetite (especially basalt) record the orientation of the Earth’s magnetic field at the time the rocks formed.
Figure 2.8a showing apparent polar wander paths for Europe and North America.
Figure 2.8b showing alignment of polar wander curves if the Atlantic Ocean is “closed”
The polar wander tracks for all the continents show great variation, suggesting it is the continents that moved!
If we put the continents “back to.
Lecture 4 Outline Plate Tectonics – Mechanisms and MarginsL.docxSHIVA101531
Lecture 4 Outline:
Plate Tectonics – Mechanisms and Margins
Learning Objectives:
What are the types of plate boundaries?
What processes occur at different types of plate boundaries?
What are hotspots?
How does tectonics build continents and ocean basins?
What Happens at Plate Boundaries?
Plate interiors stable - geologic activity limited to surface processes
But interactions between plates at plate boundaries results in
Magma and volcanism
Faulting and earthquakes
Mountain building
Production of new crust
Recycling of old crust
What are the Types of Plate Boundaries?
Divergent
plates pulled apart
Convergent
plates collide
Transform
plates sheared
Each plate surrounded by different types of boundaries
What are the Types of Plate Boundaries?
What are Divergent Plate Boundaries?
Ridges
Crust pulled apart
Magma by decompression melting in asthenosphere
Cools to make new oceanic crust
Oceanic crust
lithosphere
asthenosphere
magma
central rift valley
faults
North Atlantic Ridge
Mid-Atlantic Ridge
East Pacific Ridge
Indian Ridge
Antarctic Ridge
Where are Divergent Plate Boundaries Found?
Ocean ridge above sea level in Iceland
Where are Divergent Plate Boundaries Found?
What are the Major Geologic Features of the Ocean Ridge?
Shield Volcano
Edge of North American Plate
Fault
Down-dropped fault block
Central rift valley
Filled by lava flows
What are Convergent Plate Boundaries?
Two plates collide with each other – two types
Subduction zone
Between two plates of different density - denser plate subducted
melting in mantle by addition of water from subducted plate
Trench and volcanic arc - chain of volcanoes on overriding plate
Earthquakes
What are Convergent Plate Boundaries?
Collision zone
between plates too buoyant to subduct
Crust thickened and mountains raised instead
Earthquakes but no volcanoes
Indian Plate
Eurasian Plate
Younger and weaker
Older and stronger
deformed
Which Plate gets Subducted?
If both plates composed of oceanic crust
older and denser crust subducted by younger and lighter crust
Overriding plate
Plate boundary
Where Can We Find an Example of an Oceanic Plate Subducted by Another Oceanic Plate?
Pacific Plate subducted by Philippine Plate at Mariana Trench
Pacific Plate
(older)
Philippine Plate
(younger)
Japan Trench
Mariana Trench
Challenger Deep
Eurasian Plate
Which Plate gets Subducted?
If one plate of continental crust and one of oceanic crust
denser oceanic crust subducted by lighter continental crust
Material too light to subduct added to continent as accreted terranes
sediments, volcanic islands, fragments of continental crust
Where Can We Find an Example of a Collision Zone?
Indian and Eurasian Plates
Collision began 45 mya when subduction completely closed ocean basin
Himalaya and Tibetan Plateau
Recent or continuing collisions produce Earth’s tallest mountains
50 mya
today
Closing Ocean
Spreading Ocean
14
Oblique motion betw ...
The topic of plate tectonics is largely based on Alfred Wegner's theory of continental drift, which became accepted with the discovery of seafloor spreading in the Atlantic Ocean, and after fossil, flora, and geological studies in Africa and South America. In this lesson, students will learn about Earth’s structure, differences between various types of tectonic plate boundaries, their outcomes, and their connection to locations of volcanoes and earthquake activity.
Download the paper to access it as a word document
This is an exam style question paper (if any doubts, just comment and within days I will reply). I hope you like this. Please like and also download the pdf so you can have it as reference. Moreover, I have combined all past papers into one which is in your hands now. Please, do not hesitate if you have any doubts regarding plate boundaries/tectonic plates or even any comments to improve my work.
that is associated with broad upwarping of the overlying litho.docxmattinsonjanel
that is associated with broad upwarping of the overlying lithosphere (figure 5.1 iA). As a result, the lithosphere is stretched, causing the brittle crustal rocks to break into large slabs. As the tectonic forces continue to pull the crust apart, these crustal fragments sink, generating an elongated depression called a continental rift (figure 5.1 ib).
A modern example of an active continental rift is the East African Rift (figure s. i 2). Whether this rift will eventually result in the breakup of Africa is a topic of continued research. Nevertheless, the East African Rift is an excellent model of the initial stage in the breakup of a continent. Here, tensional forces have stretched and thinned the crust, allowing molten rock to ascend from the mantle. Evidence for recent volcanic activity includes several large volcanic mountains including Mount Kilimanjaro and Mount Kenya, the tallest peaks in Africa. Research suggests that if rifting continues, the rift valley will lengthen and deepen, eventually extending out to the margin of the landmass (r;<;ur.E 5.1 ic). At this point, the rift will become a narrow sea with an outlet to the ocean. The Red Sea, which formed when the Arabian Peninsula split from Africa, is a modern example of such a feature. Consequently, the Red Sea provides us with a view of how the Atlantic Ocean may have looked in its infancy (figure 5.1 id).
QEOD^
Forces Within sSWHBe Plate Tectonics
New lithosphere is constantly being produced at the oceanic ridges; however, our planet is not growing larger—its total surface area remains constant. A balance is maintained because older, denser portions of oceanic lithosphere descend into the mantle at a rate equal to seafloor production. This activity occurs along convergent (con = together, vergere = to move) boundaries, where two plates move toward each other and the leading edge of one is bent downward, as it slides beneath the other.
Convergent boundaries are also called subduction zones, because they are sites where lithosphere is descending (being subducted) into the mantle. Subduction occurs because the density of the descending tectonic plate is greater than the density of the underlying asthenosphere. In general, oceanic lithosphere is more dense than the asthenosphere, whereas continental lithosphere is
(
Upwarping
figure 5.11
Continental rifting and the formation of a new ocean basin.
A.
The initial stage of con tinental rifting tends to include upwelling in the mantle that is associated with broad doming of the lith-osphere.Tensional forces and buoyant uplifting of the heated lithosphere cause the crust to be broken into large slabs.
b.
A
s the crust is pulled apart, large slabs of rock sink, generating a rift valley.
C.
Further spreading generates a narrow sea, similar to the present-day Red Sea.
D.
Eventually, an expansive ocean basin and ridge system are created.
)less dense and resists subduction. As a consequence, only oceanic lithosphere will subd ...
Steps to Plate TectonicsStep 1 – Continental Driftwww.mat.docxdessiechisomjj4
Steps to Plate Tectonics:
Step 1 – Continental Drift
www.math.montana.edu / ~nmp / materials / ess / geosphere / inter / activities / plate_calc / pangaea_map.gif
The Continental Drift hypothesis published by Alfred Wegener in his 1915 book “ The Origin of Continents and Oceans”, although this was partially based on the work of earlier investigators.
Continental Drift = the continents were once connected in a single supercontinent called Pangaea. They have since drifted apart and are still moving today.
http://www.kidsgeo.com/geology-for-kids/0042-pangaea.php
Wegener’s hypothesis had several problems:
1) He had no power source – no way to make the continents move.
2) He thought the continents moved through the seafloor just like boats move through the ocean, but there was no evidence of this (no wake)
3) He was a meteorologist so many geologists didn’t take him seriously!
BUT Wegener had lots of evidence to show that the continents were once connected!
1) The jigsaw puzzle-like fit of the continents.
Figure 2.3 in text
Identical fossil assemblages on now widely spaced continents!
best about 250-200 MY ago
become increasingly dissimilar the closer to today we look!
Garrison, 2012, Essentials of Oceanography
3) Sequences of similar rock types on continents which do not now have the same geologic environment!
http://www.geology.ohio-state.edu/~vonfrese/gs100/lect25/index.html
4) Geologic structures (mountain ranges, faults, chains of volcanoes) which match up on either side of oceans but can not be found underwater.
5) Apparent polar wander – paleoclimatic evidence the continents had very different climates 250 MY ago than they do today.
either the continents moved or
the climate bands moved – which means the Earth’s poles of rotation moved.
Earth’s climate zones today are arranged symmetrically around the poles.
http://www.webquest.hawaii.edu/kahihi/sciencedictionary/C/climatezone.php
Paleoclimatic data from ˶300 MY ago, figure 2.5 in text
After Wegener died, his ideas were largely dismissed, until…
Post-Wegener evidence for drifting continents (and plate tectonics)…
6) Apparent Polar Wander – Paleomagnetic evidence.
Figure 2.7 showing that the Earth has a magnetic field very similar to that created by a bar magnet.
Directions of magnets parallel to Earth’s magnetic field lines.
Post-Wegener evidence for drifting continents (and plate tectonics)…
Figure 2.7b showing how magnets align to the Earth’s magnetic field when allowed to move freely.
Rocks containing the mineral magnetite (especially basalt) record the orientation of the Earth’s magnetic field at the time the rocks formed.
Figure 2.8a showing apparent polar wander paths for Europe and North America.
Figure 2.8b showing alignment of polar wander curves if the Atlantic Ocean is “closed”
The polar wander tracks for all the continents show great variation, suggesting it is the continents that moved!
If we put the continents “back to.
Lecture 4 Outline Plate Tectonics – Mechanisms and MarginsL.docxSHIVA101531
Lecture 4 Outline:
Plate Tectonics – Mechanisms and Margins
Learning Objectives:
What are the types of plate boundaries?
What processes occur at different types of plate boundaries?
What are hotspots?
How does tectonics build continents and ocean basins?
What Happens at Plate Boundaries?
Plate interiors stable - geologic activity limited to surface processes
But interactions between plates at plate boundaries results in
Magma and volcanism
Faulting and earthquakes
Mountain building
Production of new crust
Recycling of old crust
What are the Types of Plate Boundaries?
Divergent
plates pulled apart
Convergent
plates collide
Transform
plates sheared
Each plate surrounded by different types of boundaries
What are the Types of Plate Boundaries?
What are Divergent Plate Boundaries?
Ridges
Crust pulled apart
Magma by decompression melting in asthenosphere
Cools to make new oceanic crust
Oceanic crust
lithosphere
asthenosphere
magma
central rift valley
faults
North Atlantic Ridge
Mid-Atlantic Ridge
East Pacific Ridge
Indian Ridge
Antarctic Ridge
Where are Divergent Plate Boundaries Found?
Ocean ridge above sea level in Iceland
Where are Divergent Plate Boundaries Found?
What are the Major Geologic Features of the Ocean Ridge?
Shield Volcano
Edge of North American Plate
Fault
Down-dropped fault block
Central rift valley
Filled by lava flows
What are Convergent Plate Boundaries?
Two plates collide with each other – two types
Subduction zone
Between two plates of different density - denser plate subducted
melting in mantle by addition of water from subducted plate
Trench and volcanic arc - chain of volcanoes on overriding plate
Earthquakes
What are Convergent Plate Boundaries?
Collision zone
between plates too buoyant to subduct
Crust thickened and mountains raised instead
Earthquakes but no volcanoes
Indian Plate
Eurasian Plate
Younger and weaker
Older and stronger
deformed
Which Plate gets Subducted?
If both plates composed of oceanic crust
older and denser crust subducted by younger and lighter crust
Overriding plate
Plate boundary
Where Can We Find an Example of an Oceanic Plate Subducted by Another Oceanic Plate?
Pacific Plate subducted by Philippine Plate at Mariana Trench
Pacific Plate
(older)
Philippine Plate
(younger)
Japan Trench
Mariana Trench
Challenger Deep
Eurasian Plate
Which Plate gets Subducted?
If one plate of continental crust and one of oceanic crust
denser oceanic crust subducted by lighter continental crust
Material too light to subduct added to continent as accreted terranes
sediments, volcanic islands, fragments of continental crust
Where Can We Find an Example of a Collision Zone?
Indian and Eurasian Plates
Collision began 45 mya when subduction completely closed ocean basin
Himalaya and Tibetan Plateau
Recent or continuing collisions produce Earth’s tallest mountains
50 mya
today
Closing Ocean
Spreading Ocean
14
Oblique motion betw ...
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This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
4. a theory in geology: the
lithosphere of the earth is divided
into a small number
of plates which float on and travel
independently over the mantle
and much of the earth's seismic
activity occurs at the boundaries
of these plates
7. Entire lithosphere of the Earth is broken
into numerous segments called lithospheric
plates.
The slow but constant moving of these
plates is called tectonics, thus moving
lithospheric plates is called plate tectonics.
One of the consequences of these plate
movements is EARTHQUAKE.
8.
9.
10. Objective: Locate the epicenter
of an earthquake using
triangulation method
What data are needed?
1.At least three(3) recording stations
2.Time difference in the arrival of P-wave and S-
wave in each station
3. Distance of epicenter from each station using
the formula
14. Q1.Where is the epicenter of this hypothetical earthquake?Use
triangulation method.
- CEBU
Q2.What difficulty will you encounter if you only have data
from two recording stations?
Two recording stations would result to two epicenters.
Q3.What is the distance of the epicenter from the seismic station? -
9000 km.
Q4.What do you think is the importance of determining
the epicenter of an earthquake?
It will help in assessing the damage zone where death and
destruction will be maximum.Thus, helps in planning
post-earthquake rehabilitation and relief measures, in
forewarning of tsunami-related hazard and in assuring
of minimum loss to life and property if it is the deserted
or inhabited region
15. Let’s see how early geologists used the
plotted positions of earthquake epicenters
throughout the world in conceptualizing
crustal movements.
17. ACTIVE VOLCANOES DISTRIBUTION
Where are the volcanoes located?
Compare the location of majority of
earthquake epicenters with the location of
volcanoes
18. MOUNTAIN RANGES DISTRIBUTION
How will you relate the distribution of
mountain ranges with the distribution of
earthquake epicenters and volcanoes?
19. What do you think is the
basis of scientists in
dividing Earth’s lithosphere
into several plates?
The places on Earth where most of the
earthquakes originated or some mountains
and volcanoes were formed mark the
boundaries of each lithospheric plate.
23. PLATE BOUNDARIES (RECALL)
Determining location of earthquake epicenters
plays a vital role in laying the foundation of
plate tectonics.
The places on Earth where most of the
earthquakes originated or some of the
mountains and volcanoes were formed
marked the boundaries of each lithospheric
plates
24.
25. 3 TYPESOF PLATE BOUNDARIES
DIVERGENT PLATE BOUNDARY
2 lithospheric plates move away from
each other
CONVERGENT PLATE BOUNDARY
2 lithospheric plates move toward
each other
TRANSFORM FAULT
2 lithospheric plates slide past each other
32. Questions:
1. What are common in four
pictures?
2.Million of years ago, landmasses
in each picture were once connected
.What do you think is happening to
the Earth’s crust in those pictures?
3. If this event continues for million
of years, what do you think will be
the effect on the crust?
34. Types of divergent plate boundary
1. continental divergence
-As the two plates pull apart, normal faults develop on
both sides of the rift, and the central blocks slide
downwards
Early in the rift-forming process, streams and rivers
will flow into the sinking rift valley to form a long
linear lake.
As the rift grows deeper it might drop below sea level,
allowing ocean waters to flow in.This will produce a
narrow, shallow sea within the rift.
This rift can then grow deeper and wider. If rifting
continues, a new ocean basin could be produced.
35.
36.
37. Example
The East Africa RiftValley is a classic example of
this type of plate boundary.The East Africa Rift is
in a very early stage of development.The plate
has not been completely rifted, and the rift valley
is still above sea level but occupied by lakes at
several locations.The Red Sea is an example of a
more completely developed rift.There the plates
have fully separated, and the central rift valley
has dropped below sea level.
38. GEOLOGICAL EFFECTS
a rift valley sometimes occupied by long
linear lakes or a shallow arm of the
ocean; numerous normal faults
bounding a central rift valley;
shallow earthquake activity along the
normal faults.
Volcanic activity sometimes occurs
within the rift.
39. 2. Oceanic Divergence
When a divergent boundary occurs beneath
oceanic lithosphere, the rising convection
current below lifts the lithosphere, producing a
mid-ocean ridge.
Extensional forces stretch the lithosphere and
produce a deep fissure. When the fissure opens,
pressure is reduced on the super-heated mantle
material below.
It responds by melting, and the new magma
flows into the fissure.The magma then solidifies
and the process repeats itself.
40.
41.
42. example
The Mid-Atlantic Ridge is a classic example of
this type of plate boundary.The Ridge is a
high area compared to the surrounding
seafloor because of the lift from the
convection current below.
43. GEOLOGICAL EFFECTS
a submarine mountain range such as the Mid-
Atlantic Ridge;
volcanic activity in the form of fissure
eruptions;
shallow earthquake activity;
creation of new seafloor and a widening
ocean basin.
44.
45. …..is divergent boundary also known as
constructive plate boundary?
46. ASSESSMENT
Which of the following is NOT an example
of a divergent plate boundary?
a.The boundary between the Nazca Plate and
the South American Plate
b.The boundary between the North American
Plate and the Eurasian Plate
c.The East African Rift
d.The plate boundary that passes over Iceland
47. Which of the following describes a divergent
boundary?
a. When two plates collide with each other
b. When two plates interact in any way
c.When two plates move apart from each other
d.When two plates slide alongside each other
48. What feature forms near divergent
boundaries between two pieces of oceanic
crust?
a. Mid-ocean ridge
b. Non-volcanic mountain
c. Continental rift valley
d.Trench
49. What feature forms near divergent
boundaries between two pieces of
continental crust?
a.continental rift valley
b. non-volcanic mountain
c. mid-ocean ridge
d. canyon
52. CONVERGENT PLATE BOUNDARY
occur where the Earth’s tectonic plates collide
or move toward one another.
As the plates converge, the denser, thinner
tectonic plate subducts or dives beneath the
lighter, thicker, more buoyant tectonic plate.
55. Remember
Continental plates are thicker
but less dense than
oceanic plates.
Continental crust is too light to be carried
downward into a trench. At continental-
continental convergent margins neither plate
subducts.The two plates converge,
buckle, fold, and fault.
56. Example
Himalayas when the Indian-Australian plate
collided with the Eurasian plate.
-Alps,( collision between African and Eurasian
plate)
- Appalachians(Mountain range in the eastern
United States and Canada)
- Atlas (series of mountain ranges in
northwestern Africa)
57. GEOLOGICAL EFFECTS
intense folding and faulting;
a broad folded mountain range;
shallow earthquake activity;
shortening and thickening of the plates
within the collision zone.
58. Mount Everest, the tallest mountain in the
world, grows about 2.5 inches each year?
60. Remember
Older oceanic plates are
denser than younger ones;
denser plates subduct.
An oceanic-oceanic collision is when two
tectonic oceanic plates collide.This
convergence creates a subduction zone, which is
where one plate is submerged below the other.
61. What happens after the
subduction?
As the ocean floor crust (oceanic plate) loaded with
sediments subducts into the softer asthenosphere,
the rocks in the subduction zone
become metamorphosed (alteration of the
composition or structure of a rock) under high
pressure and temperature.
After reaching a depth of about 100 km, the plates
melt. Magma (metamorphosed sediments and the
melted part of the subducting plate) has lower
density and is at high pressure.
It rises upwards due to the buoyant force offered by
surrounding denser medium.
62. The magma flows out to the surface. A
continuous upward movement of magma
creates constant volcanic eruptions at the
ocean floor.
Constant volcanism above the subduction zone
creates layers of rocks. As this process
continues for millions of years, a volcanic
landform is created which in some cases rises
above the ocean waters.
Such volcanic landforms all along the boundary
form a chain of volcanic islands which are
collectively called as Island Arcs
63. Example
Formation of the Philippine Island Arc System
Philippine Island Arc system is formed due to subduction of Philippine
Sea plate under the Sunda Plate (major continental shelf of the Eurasian
plate).The trench formed here is called PhilippineTrench
Formation of the Indonesian Archipelago
In the case of Indonesian Archipelago, the Indo-Australian plate is
subducting below Sunda Plate (part of Eurasian Plate).The trench
formed here is called Sunda trench (JavaTrench is a major section of
Sunda trench).
Formation of the Caribbean Islands
The Caribbean Plate is moving to the east while the North American Plate
is moving to the west.
The MarianaTrench or MarianasTrench, the deepest trench, is located in
the western Pacific Ocean.
The MarianaTrench is formed due to the subduction of the Pacific
Plate below the Mariana Plate.
64. GEOLOGICAL EFFECTS
a zone of progressively deeper earthquakes;
an oceanic trench;
a chain of volcanic islands;
the destruction of oceanic lithosphere.
67. Remember
Oceanic plates are thinner
but denser than
continental plates.
When continental and oceanic plates collide, the
thinner and more dense oceanic plate is
overridden by the thicker and less dense
continental plate.The oceanic plate is forced
down into the mantle in a process known as
"subduction."
68. What happens after the
subduction?
As the ocean floor crust (oceanic plate) loaded with
sediments subducts into the softer asthenosphere,
the rocks in the subduction zone
become metamorphosed (alteration of the
composition or structure of a rock) under high
pressure and temperature.
After reaching a depth of about 100 km, the plates
melt. Magma (metamorphosed sediments and the
melted part of the subducting plate) has lower
density and is at high pressure.
It rises upwards due to the buoyant force offered by
surrounding denser medium.
69. The magma flows out to the surface.
Constant volcanism above the subduction
zone creates layers of rocks. As this
process continues for millions of years, a
volcanic landform is created
Such volcanic landforms all along the
boundary form a chain of volcano which
are collectively called as continental
volcanic arcs
70. EXAMPLES
the Cascade volcanoes along the
Washington-Oregon coast of North
America(Juan de Fuca oceanic plate is subducting
beneath the westward-moving North American
continental plate)
The Andes Mountain Range of western South
America (Nazca Plate is subducting beneath the South
American plate.)
Mount Mayon (between Eurasian plate and
Philippineplate
71. GEOLOGICAL EFFECTS
a zone of earthquake activity that is shallow
along the continent margin but deepens
beneath the continent;
an oceanic trench;
a chain of continental volcanic arc;
the destruction of oceanic lithosphere.
72. ….. convergent boundary is
also known as destructive
boundary?
75. TRANSFORM FAULT BOUNDARY
- Transform boundaries are areas where
the Earth's plates move past each other,
rubbing along the edges.
--As the plates slide across from each other,
they neither create land nor destroy it.
Because of this, they are sometimes
referred to as conservative boundaries or
margins.
76.
77. EXAMPLES
The San Andreas fault of California;
Queen Charlotte Islands fault off western
Canada
Magellanes-Fagnano fault system of South
America.
78. GEOLOGICAL EFFECTS
strike-slip faults can create deep, shallow
earthquakes.
The 2012 Sumatran quake was particularly
powerful; its 8.6 magnitude was the largest
ever recorded for a strike-slip fault.
79. Question:
If "The Big One" happens on the San
Andreas Fault, do we expect a large
tsunami? Do we expect California to
"fall into the ocean”?
No! Earthquakes at transform
boundaries, like the San Andreas fault,
involve hardly any vertical motion. For an
earthquake to generate a tsunami you
need vertical disturbance.
80. Let’s check your understanding on
different types of plate boundary.
Identify the following geological effects to as
what type of plate boundary they were
formed/created. Answer all that apply.
CHOICES
-Oceanic divergence
-Continental Divergence
-Oceanic Convergence
-Continental Convergence
-Continental-Oceanic Convergence
-Transform fault
85. Although many volcanoes form underwater
in subduction zones or at divergent plate
boundaries, some form on land. Areas
where volcanoes that form on land away
from tectonic plate boundaries are known as
hotspots.
88. Let’s check your understanding.
1. In what layer of Earth does a hotspot
volcano start?
a.The core
b.The surface
c. The mantle
d.The crust
89. Let’s check your understanding.
2. How does magma get to the Earth's crust
to create a hotspot volcano?
a. Magma travels to Earth's surface through an
upward tunnel from deep within Earth.
b. Magma is created from asteroids hitting
Earth's surface.
c. Magma is created from meteors hitting
Earth's surface.
d. Magma comes from the sky and drops to the
Earth.
90. Let’s check your understanding.
3. In a hot spot,Volcano A is on top of the
mantle plume,Volcano B is 10 km farther from
A whileVolcano C is the farthest.What can
you infer about the ages of the volcanoes?
a.Volcano A is older than C
b.VolcanoB is the oldest
c.Volcano B is the youngest
d.Volcano B is younger than C
91. By: DARYL F. CADANILLA
End of module 1
First quarter
Grade 10 science