Evidence is given that the ejecta blanket of the 35.5-Myr-old Chesapeake Bay crater is still extant and covers ~5,000 km2 of the U.S. mid Atlantic Coastal Plain (Part 1 of 3)
The document summarizes John Schlee's 1957 study of the "upland deposits" of southern Maryland and presents an alternative hypothesis that these deposits originated from ejecta from the Chesapeake Bay crater. Schlee had analyzed the deposits and determined they could not have been formed through fluvial processes, but he was unaware of the crater's existence. The author notes issues with the accepted fluvial model and presents evidence from Schlee's data that the cobble sizes decrease with distance in a pattern suggestive of atmospheric sorting during ejection from an impact, with the direction of the crater at the origin point.
This document discusses various topics related to Earth science including:
1. The different spheres that make up Earth's system - lithosphere, hydrosphere, atmosphere, and biosphere. It mentions rivers, ocean currents, cloud patterns, and the carbon cycle within the atmosphere.
2. Geologic time periods from the Precambrian to present day. A chart shows the geologic time scale with eras, periods, epochs, and ages ranging from the Hadean to the Holocene.
3. Examples of prehistoric life such as Basilosaurus and Titanis & Hipparian. It notes how studying historical geology helps understand the past environment and potential future impacts.
1. The document discusses sea-floor spreading, which is the process where new oceanic crust forms at mid-ocean ridges as tectonic plates move away from each other.
2. Evidence that supports sea-floor spreading includes magnetic stripe patterns in the ocean floor and samples from ocean crust that show it is younger near ridges and older further away.
3. Oceanic crust is basaltic rock that forms at ridges and is then recycled in subduction zones, making it generally younger than continental crust which does not undergo this recycling process.
This document discusses plate tectonics and the theory of plate tectonics. It provides information on key aspects of plate tectonics including:
- The lithosphere is broken into individual plates that move over the asthenosphere in response to convection currents.
- Plate boundaries are sites of geologic activity including divergent boundaries which create oceanic crust, transform boundaries, and convergent boundaries involving subduction or collision which alter crust composition.
- Mantle convection provides the primary driving force for plate tectonics, with slab pull and ridge push contributing to plate motions.
Rock samples near mid-ocean ridges provided evidence for sea floor spreading. The youngest rocks were found near the ridges, with older rocks located farther away, showing that new crust was being created at the ridges over time. Additional evidence came from magnetic striping patterns in the rocks, which recorded changes in Earth's magnetic field during the formation of new ocean crust along the ridges. Hydrothermal vents at the ridges also indicated that magma chambers must be close to the surface in order to heat the water emerging from the vents.
In this presentation,it is taking about plate tectonics and sea floor spreading with suitable diagrams respectively. During and just after World War II, the technological improvement to submarines led to an improvement in underwater navigation and surveying that revealed many intriguing underwater features. The most important of these were immense, continuous chains of volcanic mountains running along the ocean basins. These features are now termed mid-ocean ridges or more accurately, oceanic ridge systems.
Scientists in the 1950s used sonar to map the mid-ocean ridge and discovered it was not flat but contained underwater mountains. This discovery led them to research what the ridge was and how it formed. Evidence from molten rock samples, magnetic stripes in the ocean crust, and the ages of rocks drilled from the ocean floor supported Harry Hess' theory from 1960 of sea-floor spreading, where new crust forms at mid-ocean ridges and spreads outward over time.
1) Tubeworms survive through a symbiotic relationship with bacteria that live inside them. The bacteria convert chemicals from deep sea vents into food for the worm.
2) Sonar uses sound waves to determine the distance to underwater objects by measuring the echo return time.
3) Sea-floor spreading was discovered by Harry Hess in the 1960s and explains how new ocean crust continually forms at mid-ocean ridges, pushing older rocks away.
The document summarizes John Schlee's 1957 study of the "upland deposits" of southern Maryland and presents an alternative hypothesis that these deposits originated from ejecta from the Chesapeake Bay crater. Schlee had analyzed the deposits and determined they could not have been formed through fluvial processes, but he was unaware of the crater's existence. The author notes issues with the accepted fluvial model and presents evidence from Schlee's data that the cobble sizes decrease with distance in a pattern suggestive of atmospheric sorting during ejection from an impact, with the direction of the crater at the origin point.
This document discusses various topics related to Earth science including:
1. The different spheres that make up Earth's system - lithosphere, hydrosphere, atmosphere, and biosphere. It mentions rivers, ocean currents, cloud patterns, and the carbon cycle within the atmosphere.
2. Geologic time periods from the Precambrian to present day. A chart shows the geologic time scale with eras, periods, epochs, and ages ranging from the Hadean to the Holocene.
3. Examples of prehistoric life such as Basilosaurus and Titanis & Hipparian. It notes how studying historical geology helps understand the past environment and potential future impacts.
1. The document discusses sea-floor spreading, which is the process where new oceanic crust forms at mid-ocean ridges as tectonic plates move away from each other.
2. Evidence that supports sea-floor spreading includes magnetic stripe patterns in the ocean floor and samples from ocean crust that show it is younger near ridges and older further away.
3. Oceanic crust is basaltic rock that forms at ridges and is then recycled in subduction zones, making it generally younger than continental crust which does not undergo this recycling process.
This document discusses plate tectonics and the theory of plate tectonics. It provides information on key aspects of plate tectonics including:
- The lithosphere is broken into individual plates that move over the asthenosphere in response to convection currents.
- Plate boundaries are sites of geologic activity including divergent boundaries which create oceanic crust, transform boundaries, and convergent boundaries involving subduction or collision which alter crust composition.
- Mantle convection provides the primary driving force for plate tectonics, with slab pull and ridge push contributing to plate motions.
Rock samples near mid-ocean ridges provided evidence for sea floor spreading. The youngest rocks were found near the ridges, with older rocks located farther away, showing that new crust was being created at the ridges over time. Additional evidence came from magnetic striping patterns in the rocks, which recorded changes in Earth's magnetic field during the formation of new ocean crust along the ridges. Hydrothermal vents at the ridges also indicated that magma chambers must be close to the surface in order to heat the water emerging from the vents.
In this presentation,it is taking about plate tectonics and sea floor spreading with suitable diagrams respectively. During and just after World War II, the technological improvement to submarines led to an improvement in underwater navigation and surveying that revealed many intriguing underwater features. The most important of these were immense, continuous chains of volcanic mountains running along the ocean basins. These features are now termed mid-ocean ridges or more accurately, oceanic ridge systems.
Scientists in the 1950s used sonar to map the mid-ocean ridge and discovered it was not flat but contained underwater mountains. This discovery led them to research what the ridge was and how it formed. Evidence from molten rock samples, magnetic stripes in the ocean crust, and the ages of rocks drilled from the ocean floor supported Harry Hess' theory from 1960 of sea-floor spreading, where new crust forms at mid-ocean ridges and spreads outward over time.
1) Tubeworms survive through a symbiotic relationship with bacteria that live inside them. The bacteria convert chemicals from deep sea vents into food for the worm.
2) Sonar uses sound waves to determine the distance to underwater objects by measuring the echo return time.
3) Sea-floor spreading was discovered by Harry Hess in the 1960s and explains how new ocean crust continually forms at mid-ocean ridges, pushing older rocks away.
Seafloor spreading is the process by which new oceanic crust is formed through volcanic activity at mid-ocean ridges, pushing the tectonic plates apart. Magma rises through cracks between the plates and hardens into new crust, causing the plates to spread further. This spreading helps explain continental drift and the theory of plate tectonics.
Scientists in the 1950s used sonar to map the mid-ocean ridge and discovered it was not flat but made of underwater mountains. This discovery led them to research what the ridge was and how it formed. Evidence from molten rock formations, magnetic patterns in the ocean crust, and sediment core samples supported Harry Hess's theory from 1960 that the ocean floors spread from the mid-ocean ridge in a conveyor belt-like motion, pushing the continents. This process of sea-floor spreading continually recycles the ocean crust through subduction at deep ocean trenches.
This document discusses evidence of liquid water on ancient Mars and results from the Mars Exploration Rover missions. It summarizes that mineralogical evidence and features like valley networks and outflow channels indicate there was standing water on Mars' surface for extended periods in the past. The rovers found evidence of water interaction at both landing sites, including coatings on rocks with higher sulfur and chlorine concentrations than the interiors and crystalline hematite, providing evidence of limited but unequivocal water involvement. Current understanding is that acid water was present on Mars' surface for long periods in the Noachian era.
The document discusses the theory of seafloor spreading, where new ocean crust is formed at mid-ocean ridges as tectonic plates move apart, and magnetic patterns in rocks on the ocean floor provide evidence of periodic reversals of the Earth's magnetic field. Analysis of magnetic stripes on both sides of ocean ridges that appear to be mirror images supports the idea that the seafloor is actively spreading.
Continental drift &and sea floor spreadingMd Asif Hasan
The document discusses the theories of continental drift, seafloor spreading, and plate tectonics. It provides details on the original proponent of continental drift theory, Alfred Wegener, in 1915. It also outlines various geological, climatic, and biological evidence that supports continental drift. The document then discusses the sea floor spreading theory proposed by Harry Hess in the 1960s, which helped explain continental drift. It notes evidence that the ocean floor becomes progressively younger near mid-ocean ridges. Finally, it describes how the theories of continental drift and sea floor spreading were combined into the comprehensive theory of plate tectonics.
Earth and Life Science
Earth Materials and Processes: Deformation of the Crust
The learners shall be able to:
1) explain how the seafloor spreads (S11/12ESId-23);
2) describe the structure and evolution of ocean basins (S11/12ES-Id-24); and
3) explain how the movement of plates leads to the formation of folds and faults (S11/12ES-Id-22).
Specific Learning Outcomes
At the end of the lesson, the learners will be able to:
1. Discuss the history behind the Theory of Continental Drift;
2. Describe the Continental Drift Theory;
3. Enumerate and explain the evidence used to support the idea of drifting continents;
4. Identify major physiographic features of ocean basins
5. Describe the process of seafloor spreading
Magma rises from the Earth's interior along mid-ocean ridges, cooling and forming new seafloor. According to the theory of seafloor spreading, sediments should be thicker and older further from ridges, where the seafloor is younger near ridges and ages farther away. Drilling in the 1960s validated this by finding thicker, older sediments located farther from ridge centers, consistent with the fossil record.
Geology is the scientific study of the origin, history, and structure of the Earth based on observable data and the principle of uniformitarianism. Observable data can be qualitative descriptions or quantitative measurements. In the 17th century, Irish Bishop James Usher estimated the age of the Earth to be around 4004 BC based on biblical accounts, but in the 18th century, Scottish geologist James Hutton developed the principle of uniformitarianism from his observations of rock formations. Modern geology uses both relative dating methods based on principles like superposition and cross-cutting relationships, as well as absolute dating techniques like radiometric dating to determine ages of rocks and the Earth in the billions of years.
Taylor proposed the concept of continental drift in 1908, hypothesizing that continents had shifted horizontally across Earth's surface over geological time. He suggested that the Arctic Sea was formed when Greenland and Siberia drifted apart, and that gaps between landmasses were filled by water to form oceans like the Atlantic and Indian Ocean. Taylor's continental drift theory was one of the first attempts to explain observations that seemed to support the idea of continental plate movements.
The document discusses three types of plate boundaries:
1) Divergent boundaries, where plates pull apart and new crust is formed, examples include mid-ocean ridges and continental rift valleys.
2) Convergent boundaries, where plates push together, examples include oceanic-continental collisions which form volcanoes and trenches, and oceanic-oceanic collisions which form island arcs.
3) Transform boundaries, where plates slide horizontally past one another along transform faults.
1) The Earth is composed of layers including a solid iron core, liquid outer core, and thin crust floating on the mantle.
2) Plate tectonics involves the movement of tectonic plates which are sections of the Earth's crust. As the plates move they cause earthquakes, create and spread ocean floors, and can cause collisions that form mountains.
3) Alfred Wegener first proposed the theory of continental drift in which he suggested that continents move across Earth's surface, an idea that was not widely accepted until additional evidence supported plate tectonics.
New evidence supported the theory of sea floor spreading and plate tectonics. Mapping of the seafloor using sonar revealed a mid-ocean ridge running through the Atlantic Ocean. Rocks near the ridge are younger, becoming progressively older further from the ridge, showing new crust is generated at the ridge through sea floor spreading. While new crust is created at ridges, older oceanic crust is recycled back into the Earth through subduction at plate boundaries, keeping the size of the Earth stable over time. This evidence of sea floor spreading supported Wegener's theory of continental drift.
The document discusses plate tectonics, including that the Earth's crust is broken into plates that move atop the mantle. There are two types of plates - oceanic and continental. Plates interact at three types of boundaries: divergent boundaries where plates separate and new seafloor is created, convergent boundaries where plates collide resulting in subduction zones or mountain building, and transform boundaries where plates slide past one another causing earthquakes. Convection currents in the underlying mantle are cited as the cause of plate tectonic movement.
The document discusses continental drift and plate tectonics. It explains that continental drift was first proposed in the 16th century and was further developed and advocated for by Alfred Wegener in the early 20th century. Wegener proposed that the continents were once joined together in a supercontinent called Pangaea, which began breaking apart about 200 million years ago. The theory of plate tectonics posits that the Earth's crust is broken into plates that move over time, interacting through processes like seafloor spreading at mid-ocean ridges, subduction at convergent boundaries, and lateral movement at transform boundaries.
The document summarizes evidence that supports the theory of seafloor spreading and plate tectonics. It describes how Harry Hess first proposed in 1962 that new ocean crust is formed at mid-ocean ridges through volcanic activity and magma cooling. As more magma is added, it pushes older ocean crust further from the ridges, providing evidence that the plates are moving. Studies of magnetic reversals in ocean floor basalts also indicate the age of the crust increases further from ridges, confirming seafloor is continually being created and destroyed over time.
This document describes plate tectonics and the evidence that supports it. It explains the three main types of plate boundaries - divergent boundaries where plates move apart, convergent boundaries where they collide, and transform boundaries where they slide past each other. It provides details on subduction zones, island arcs, and mountain building. The document also discusses mantle plumes and uses the Hawaiian Islands as an example of a hotspot track. It includes a hypothetical tectonic map exercise asking students to interpret earthquake and age data to identify plate boundaries.
This document discusses the geologic time scale and the history of life on Earth. It describes how paleontologists divide Earth's history into major eras including the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras. Each era is characterized by the dominant life forms present in the rocks and fossils from that time period. The document also discusses concepts like mass extinctions, absolute dating using radioactive decay, and half-life.
The document summarizes key facts about the dynamic Earth. It describes the different layers of the Earth including the crust, mantle, and core. The crust is divided into continental and oceanic crust of varying thicknesses. The mantle makes up most of the Earth's mass and is divided into lithosphere, asthenosphere, and mesosphere layers. The core is divided into a solid inner core and liquid outer core. The document also briefly outlines the Earth's rotation, revolution around the sun, and reasons for the seasons.
Evidence is given that the ejecta blanket of the 35.5-Myr-old Chesapeake Bay Crater is still extant and covers ~5,000 km2 of the U.S. mid Atlantic Coastal plain
Evidence is presented that the ejecta blanket of the 35.5-Myr-old Chesapeake Bay crater is still extant and covers ~5,000 km2 of the U.S. mid Atlantic Coastal Plain. (Part 3 of 3)
Seafloor spreading is the process by which new oceanic crust is formed through volcanic activity at mid-ocean ridges, pushing the tectonic plates apart. Magma rises through cracks between the plates and hardens into new crust, causing the plates to spread further. This spreading helps explain continental drift and the theory of plate tectonics.
Scientists in the 1950s used sonar to map the mid-ocean ridge and discovered it was not flat but made of underwater mountains. This discovery led them to research what the ridge was and how it formed. Evidence from molten rock formations, magnetic patterns in the ocean crust, and sediment core samples supported Harry Hess's theory from 1960 that the ocean floors spread from the mid-ocean ridge in a conveyor belt-like motion, pushing the continents. This process of sea-floor spreading continually recycles the ocean crust through subduction at deep ocean trenches.
This document discusses evidence of liquid water on ancient Mars and results from the Mars Exploration Rover missions. It summarizes that mineralogical evidence and features like valley networks and outflow channels indicate there was standing water on Mars' surface for extended periods in the past. The rovers found evidence of water interaction at both landing sites, including coatings on rocks with higher sulfur and chlorine concentrations than the interiors and crystalline hematite, providing evidence of limited but unequivocal water involvement. Current understanding is that acid water was present on Mars' surface for long periods in the Noachian era.
The document discusses the theory of seafloor spreading, where new ocean crust is formed at mid-ocean ridges as tectonic plates move apart, and magnetic patterns in rocks on the ocean floor provide evidence of periodic reversals of the Earth's magnetic field. Analysis of magnetic stripes on both sides of ocean ridges that appear to be mirror images supports the idea that the seafloor is actively spreading.
Continental drift &and sea floor spreadingMd Asif Hasan
The document discusses the theories of continental drift, seafloor spreading, and plate tectonics. It provides details on the original proponent of continental drift theory, Alfred Wegener, in 1915. It also outlines various geological, climatic, and biological evidence that supports continental drift. The document then discusses the sea floor spreading theory proposed by Harry Hess in the 1960s, which helped explain continental drift. It notes evidence that the ocean floor becomes progressively younger near mid-ocean ridges. Finally, it describes how the theories of continental drift and sea floor spreading were combined into the comprehensive theory of plate tectonics.
Earth and Life Science
Earth Materials and Processes: Deformation of the Crust
The learners shall be able to:
1) explain how the seafloor spreads (S11/12ESId-23);
2) describe the structure and evolution of ocean basins (S11/12ES-Id-24); and
3) explain how the movement of plates leads to the formation of folds and faults (S11/12ES-Id-22).
Specific Learning Outcomes
At the end of the lesson, the learners will be able to:
1. Discuss the history behind the Theory of Continental Drift;
2. Describe the Continental Drift Theory;
3. Enumerate and explain the evidence used to support the idea of drifting continents;
4. Identify major physiographic features of ocean basins
5. Describe the process of seafloor spreading
Magma rises from the Earth's interior along mid-ocean ridges, cooling and forming new seafloor. According to the theory of seafloor spreading, sediments should be thicker and older further from ridges, where the seafloor is younger near ridges and ages farther away. Drilling in the 1960s validated this by finding thicker, older sediments located farther from ridge centers, consistent with the fossil record.
Geology is the scientific study of the origin, history, and structure of the Earth based on observable data and the principle of uniformitarianism. Observable data can be qualitative descriptions or quantitative measurements. In the 17th century, Irish Bishop James Usher estimated the age of the Earth to be around 4004 BC based on biblical accounts, but in the 18th century, Scottish geologist James Hutton developed the principle of uniformitarianism from his observations of rock formations. Modern geology uses both relative dating methods based on principles like superposition and cross-cutting relationships, as well as absolute dating techniques like radiometric dating to determine ages of rocks and the Earth in the billions of years.
Taylor proposed the concept of continental drift in 1908, hypothesizing that continents had shifted horizontally across Earth's surface over geological time. He suggested that the Arctic Sea was formed when Greenland and Siberia drifted apart, and that gaps between landmasses were filled by water to form oceans like the Atlantic and Indian Ocean. Taylor's continental drift theory was one of the first attempts to explain observations that seemed to support the idea of continental plate movements.
The document discusses three types of plate boundaries:
1) Divergent boundaries, where plates pull apart and new crust is formed, examples include mid-ocean ridges and continental rift valleys.
2) Convergent boundaries, where plates push together, examples include oceanic-continental collisions which form volcanoes and trenches, and oceanic-oceanic collisions which form island arcs.
3) Transform boundaries, where plates slide horizontally past one another along transform faults.
1) The Earth is composed of layers including a solid iron core, liquid outer core, and thin crust floating on the mantle.
2) Plate tectonics involves the movement of tectonic plates which are sections of the Earth's crust. As the plates move they cause earthquakes, create and spread ocean floors, and can cause collisions that form mountains.
3) Alfred Wegener first proposed the theory of continental drift in which he suggested that continents move across Earth's surface, an idea that was not widely accepted until additional evidence supported plate tectonics.
New evidence supported the theory of sea floor spreading and plate tectonics. Mapping of the seafloor using sonar revealed a mid-ocean ridge running through the Atlantic Ocean. Rocks near the ridge are younger, becoming progressively older further from the ridge, showing new crust is generated at the ridge through sea floor spreading. While new crust is created at ridges, older oceanic crust is recycled back into the Earth through subduction at plate boundaries, keeping the size of the Earth stable over time. This evidence of sea floor spreading supported Wegener's theory of continental drift.
The document discusses plate tectonics, including that the Earth's crust is broken into plates that move atop the mantle. There are two types of plates - oceanic and continental. Plates interact at three types of boundaries: divergent boundaries where plates separate and new seafloor is created, convergent boundaries where plates collide resulting in subduction zones or mountain building, and transform boundaries where plates slide past one another causing earthquakes. Convection currents in the underlying mantle are cited as the cause of plate tectonic movement.
The document discusses continental drift and plate tectonics. It explains that continental drift was first proposed in the 16th century and was further developed and advocated for by Alfred Wegener in the early 20th century. Wegener proposed that the continents were once joined together in a supercontinent called Pangaea, which began breaking apart about 200 million years ago. The theory of plate tectonics posits that the Earth's crust is broken into plates that move over time, interacting through processes like seafloor spreading at mid-ocean ridges, subduction at convergent boundaries, and lateral movement at transform boundaries.
The document summarizes evidence that supports the theory of seafloor spreading and plate tectonics. It describes how Harry Hess first proposed in 1962 that new ocean crust is formed at mid-ocean ridges through volcanic activity and magma cooling. As more magma is added, it pushes older ocean crust further from the ridges, providing evidence that the plates are moving. Studies of magnetic reversals in ocean floor basalts also indicate the age of the crust increases further from ridges, confirming seafloor is continually being created and destroyed over time.
This document describes plate tectonics and the evidence that supports it. It explains the three main types of plate boundaries - divergent boundaries where plates move apart, convergent boundaries where they collide, and transform boundaries where they slide past each other. It provides details on subduction zones, island arcs, and mountain building. The document also discusses mantle plumes and uses the Hawaiian Islands as an example of a hotspot track. It includes a hypothetical tectonic map exercise asking students to interpret earthquake and age data to identify plate boundaries.
This document discusses the geologic time scale and the history of life on Earth. It describes how paleontologists divide Earth's history into major eras including the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras. Each era is characterized by the dominant life forms present in the rocks and fossils from that time period. The document also discusses concepts like mass extinctions, absolute dating using radioactive decay, and half-life.
The document summarizes key facts about the dynamic Earth. It describes the different layers of the Earth including the crust, mantle, and core. The crust is divided into continental and oceanic crust of varying thicknesses. The mantle makes up most of the Earth's mass and is divided into lithosphere, asthenosphere, and mesosphere layers. The core is divided into a solid inner core and liquid outer core. The document also briefly outlines the Earth's rotation, revolution around the sun, and reasons for the seasons.
Evidence is given that the ejecta blanket of the 35.5-Myr-old Chesapeake Bay Crater is still extant and covers ~5,000 km2 of the U.S. mid Atlantic Coastal plain
Evidence is presented that the ejecta blanket of the 35.5-Myr-old Chesapeake Bay crater is still extant and covers ~5,000 km2 of the U.S. mid Atlantic Coastal Plain. (Part 3 of 3)
The document provides a summary of the geology tour given by Mike Stoever of the Washington D.C. area. It discusses the major geological processes that led to the formation of the area, including plate tectonics, erosion and deposition, a meteorite impact, and sea level changes. It then describes the four main geological provinces that make up the D.C. area, and highlights several important geological features, such as the Fall Line, Teddy Roosevelt Island, and Great Falls Park.
- 11,700 years ago, the Wisconsinian glacier receded from North America, ending the Pleistocene epoch and leaving behind glacial deposits.
- The researcher examined gravel pits in Crawford County, PA to observe bedding and measure the strike and dip of clasts to determine the paleoflow direction of ancient glacial rivers.
- At 5 of the 35 gravel pits studied, clast imbrications indicated consistent southward paleoflow, suggesting present drainage patterns are inherited from Pleistocene systems. However, too few sites showed visible imbrications to construct an accurate paleoflow map.
Orchard Beach, Pelham BayVirtual Field TripWhere are.docxhopeaustin33688
Orchard Beach, Pelham Bay
Virtual Field Trip
Where are we going?
• Orchard Beach at Pelham Bay
Park in Bronx, Northernmost
borough of NYC
• From the parking lot, walk on
the gravel path past tennis
courts toward the sound, then
walk NE along the beach to Twin
Islands
• This 10-20 minute walk will
include several stops
What are we going to see?
• Hartland formation: exotic terrane
(islands off the coast of Africa) that
collided with North America ~440 ma
• Devonian intrusions into the Cambro-
Ordovician rocks
• Evidence of glaciation (Wisconsin ice
sheet, 1000 ft thick in this part of NY, ~11
ka -80 ka)
• Sediments that were metamorphosed
during Taconic and Acadian orogenies
• Quartz-feldspar gneiss, biotite-sillimanite
schist, amphibolite
• Glacial till, glacial erratics, striations,
outwash plain, terminal moraine in the
distance
Map of NYC geology – US geological Survey
Tectonic evolution of the east coast:
• Follow along with this cartoon version of the
area’s tectonic history in your handout
• Overview:
• Grenville Orogeny completed the assembly of
Rodinia, ~1.5-1 ba
• Post-Grenville rifting created Iapetus ocean
• Iapetus ocean started closing
• Three pulses of Appalachian mountain building,
Taconian, Acadian, and Alleghanian orogenies,
close Iapetus Ocean
• Pangea breaks up in the Mesozoic, rifting creates
Atlantic ocean
• In this field trip we have glimpses into two of
the three pulses of Appalachian mountain-
building during early stages of Iapetan
closure: the Taconic Orogeny (Cambro-
Ordovician), and the Acadian Orogeny (late
Devonian)
Adapted from Earth: Portrait of a Planet by Steve
Marshak
Glaciation and 1st stop
• The top stratigraphic layers are much
younger than the tectonic events
described in the previous slide
• Ice age in the Pleistocene shaped
landscape, modified drainage, and eroded
strata
• Last advance of ice: Wisconsin stage of
the Laurentide ice sheet
• Terminal moraine at the edge of the ice
sheet creates Long Island
• Long Island Sound was a glacial lake; as
climate warmed and sea level rose, the
outwash lake became an estuary then a
sound; tall points of the moraine are now
islands
2nd stop: Hartland formation
• Hartland formation: exotic terrane
(islands off the coast of Africa) that
collided with North America ~440 ma
• Sediments that were metamorphosed
during two of the three pulses of
Appalachian mountain building:
Taconic and Acadian orogenies (check
tectonic evolution cartoon in your
handout)
• Quartz-feldspar gneiss, biotite-
sillimanite schist, amphibolite
• Follow the links; hope you can hear
me over the wind!
• https://youtu.be/aXcqGEgAH2k
• Severe deformation
• Partial melting of the schists and
gneiss produced abundant quartz-
feldspar leucosomes
• Leucosomes: lenticular shape, coarse-
grained, variable thickness, high-grade
metamorphism product
• Garnets: metamorphic index mineral
• https://youtu.be/j8YZUQW.
Orchard Beach, Pelham BayVirtual Field TripWhere arelianaalbee2qly
Orchard Beach, Pelham Bay
Virtual Field Trip
Where are we going?
• Orchard Beach at Pelham Bay
Park in Bronx, Northernmost
borough of NYC
• From the parking lot, walk on
the gravel path past tennis
courts toward the sound, then
walk NE along the beach to Twin
Islands
• This 10-20 minute walk will
include several stops
What are we going to see?
• Hartland formation: exotic terrane
(islands off the coast of Africa) that
collided with North America ~440 ma
• Devonian intrusions into the Cambro-
Ordovician rocks
• Evidence of glaciation (Wisconsin ice
sheet, 1000 ft thick in this part of NY, ~11
ka -80 ka)
• Sediments that were metamorphosed
during Taconic and Acadian orogenies
• Quartz-feldspar gneiss, biotite-sillimanite
schist, amphibolite
• Glacial till, glacial erratics, striations,
outwash plain, terminal moraine in the
distance
Map of NYC geology – US geological Survey
Tectonic evolution of the east coast:
• Follow along with this cartoon version of the
area’s tectonic history in your handout
• Overview:
• Grenville Orogeny completed the assembly of
Rodinia, ~1.5-1 ba
• Post-Grenville rifting created Iapetus ocean
• Iapetus ocean started closing
• Three pulses of Appalachian mountain building,
Taconian, Acadian, and Alleghanian orogenies,
close Iapetus Ocean
• Pangea breaks up in the Mesozoic, rifting creates
Atlantic ocean
• In this field trip we have glimpses into two of
the three pulses of Appalachian mountain-
building during early stages of Iapetan
closure: the Taconic Orogeny (Cambro-
Ordovician), and the Acadian Orogeny (late
Devonian)
Adapted from Earth: Portrait of a Planet by Steve
Marshak
Glaciation and 1st stop
• The top stratigraphic layers are much
younger than the tectonic events
described in the previous slide
• Ice age in the Pleistocene shaped
landscape, modified drainage, and eroded
strata
• Last advance of ice: Wisconsin stage of
the Laurentide ice sheet
• Terminal moraine at the edge of the ice
sheet creates Long Island
• Long Island Sound was a glacial lake; as
climate warmed and sea level rose, the
outwash lake became an estuary then a
sound; tall points of the moraine are now
islands
2nd stop: Hartland formation
• Hartland formation: exotic terrane
(islands off the coast of Africa) that
collided with North America ~440 ma
• Sediments that were metamorphosed
during two of the three pulses of
Appalachian mountain building:
Taconic and Acadian orogenies (check
tectonic evolution cartoon in your
handout)
• Quartz-feldspar gneiss, biotite-
sillimanite schist, amphibolite
• Follow the links; hope you can hear
me over the wind!
• https://youtu.be/aXcqGEgAH2k
• Severe deformation
• Partial melting of the schists and
gneiss produced abundant quartz-
feldspar leucosomes
• Leucosomes: lenticular shape, coarse-
grained, variable thickness, high-grade
metamorphism product
• Garnets: metamorphic index mineral
• https://youtu.be/j8YZUQW ...
Orchard Beach, Pelham BayVirtual Field TripWhere are.docxjacksnathalie
Orchard Beach, Pelham Bay
Virtual Field Trip
Where are we going?
• Orchard Beach at Pelham Bay
Park in Bronx, Northernmost
borough of NYC
• From the parking lot, walk on
the gravel path past tennis
courts toward the sound, then
walk NE along the beach to Twin
Islands
• This 10-20 minute walk will
include several stops
What are we going to see?
• Hartland formation: exotic terrane
(islands off the coast of Africa) that
collided with North America ~440 ma
• Devonian intrusions into the Cambro-
Ordovician rocks
• Evidence of glaciation (Wisconsin ice
sheet, 1000 ft thick in this part of NY, ~11
ka -80 ka)
• Sediments that were metamorphosed
during Taconic and Acadian orogenies
• Quartz-feldspar gneiss, biotite-sillimanite
schist, amphibolite
• Glacial till, glacial erratics, striations,
outwash plain, terminal moraine in the
distance
Map of NYC geology – US geological Survey
Tectonic evolution of the east coast:
• Follow along with this cartoon version of the
area’s tectonic history in your handout
• Overview:
• Grenville Orogeny completed the assembly of
Rodinia, ~1.5-1 ba
• Post-Grenville rifting created Iapetus ocean
• Iapetus ocean started closing
• Three pulses of Appalachian mountain building,
Taconian, Acadian, and Alleghanian orogenies,
close Iapetus Ocean
• Pangea breaks up in the Mesozoic, rifting creates
Atlantic ocean
• In this field trip we have glimpses into two of
the three pulses of Appalachian mountain-
building during early stages of Iapetan
closure: the Taconic Orogeny (Cambro-
Ordovician), and the Acadian Orogeny (late
Devonian)
Adapted from Earth: Portrait of a Planet by Steve
Marshak
Glaciation and 1st stop
• The top stratigraphic layers are much
younger than the tectonic events
described in the previous slide
• Ice age in the Pleistocene shaped
landscape, modified drainage, and eroded
strata
• Last advance of ice: Wisconsin stage of
the Laurentide ice sheet
• Terminal moraine at the edge of the ice
sheet creates Long Island
• Long Island Sound was a glacial lake; as
climate warmed and sea level rose, the
outwash lake became an estuary then a
sound; tall points of the moraine are now
islands
2nd stop: Hartland formation
• Hartland formation: exotic terrane
(islands off the coast of Africa) that
collided with North America ~440 ma
• Sediments that were metamorphosed
during two of the three pulses of
Appalachian mountain building:
Taconic and Acadian orogenies (check
tectonic evolution cartoon in your
handout)
• Quartz-feldspar gneiss, biotite-
sillimanite schist, amphibolite
• Follow the links; hope you can hear
me over the wind!
• https://youtu.be/aXcqGEgAH2k
• Severe deformation
• Partial melting of the schists and
gneiss produced abundant quartz-
feldspar leucosomes
• Leucosomes: lenticular shape, coarse-
grained, variable thickness, high-grade
metamorphism product
• Garnets: metamorphic index mineral
• https://youtu.be/j8YZUQW.
its about earth quake
Some plates have continents; some don't. All are in motion. Question: What evidence is there for these plate boundaries? Tectonic Plates ...
The Grand Canyon formed through a combination of uplift of the Colorado Plateau and incision by the Colorado River. Two main theories for its formation are the Headward Erosion Theory, which involves capture of an ancestral river by upstream erosion, and the Spillover Theory, where a blocked river spilled over the plateau. Both theories have issues, and the exact timeline and mechanisms are still debated. Uplift starting around 80 million years ago drove stream capture and erosion that excavated the canyon over millions of years.
The document summarizes the key principles of plate tectonics. It describes how the lithosphere is composed of rigid tectonic plates that move across the asthenosphere. The three main types of plate boundaries are divergent boundaries where plates move apart, convergent boundaries where they move together, and transform boundaries where they slide past each other. Evidence that supports plate tectonics includes the distribution and age of ocean floor, magnetic patterns in rocks, paleomagnetic data, polar wander curves, and geological features correlated across continents.
The document discusses the geological time scale and plate tectonics. It describes how the geological time scale is divided into eons, eras, periods, and epochs based on fossil evidence. It then outlines the early development of the continental drift theory and its shortcomings. Finally, it summarizes the current model of plate tectonics, where the lithosphere is divided into plates that move via spreading at mid-ocean ridges, collision at plate boundaries, and sliding at transform faults.
The document summarizes the geology of the Washington D.C. area, which was shaped by plate tectonics that formed the Appalachian Mountains and Atlantic Ocean over time. The area was also impacted by a large meteorite 35 million years ago that created the Chesapeake Bay crater. The geology includes coastal plain sediments, the Piedmont plateau of metamorphic rocks, and Blue Ridge mountains. Notable geological features in the D.C. area discussed include the Potomac River terraces and fall line, Great Falls Park showing elevation changes, and Rock Creek Park exhibiting different rock types.
Were Most of Earth's Fossil-Bering Sedimentary Rock Layers Deposited by Noah'...Tim Helble
This presentation uses the Coconino Sandstone to evaluate the question of whether it is quantitatively reasonable for sedimentary formations to have been deposited by Noah's Flood.
The following set of slides were used by Chris McLindon in a presentation given to the New Orleans American Planning Association on August 31st, 2016. The presentation was made on behalf of the New Orleans Geological Society as part of an informal public outreach effort. You may reach Chris McLindon at chris_mclindon@att.net
This document provides an overview of plate tectonics and the key individuals and discoveries that led to the development of the theory. It discusses Alfred Wegener's idea of continental drift in the early 20th century, which was initially rejected. It then covers the discoveries of the mid-ocean ridge system and magnetic striping of the ocean floor in the 1950s-60s, which provided evidence that the continents are moving and new crust is generated at ocean ridges through seafloor spreading. This led to the acceptance of plate tectonics as a scientific theory to explain geological phenomena.
The document provides an overview of several geological models that were used in the early 20th century to understand global geological features, including continental drift. It discusses the theory of contractionism, which proposed that continents separated as the Earth cooled and shrank. It also discusses permanentenism, which argued that continents have always been in largely the same positions. The land-bridge hypothesis suggested that land bridges once connected continents to explain terrestrial fossil distributions. The document examines problems with each of these early models and how they helped address questions about matching fossil distributions across continents.
Plate Tectonic is a theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over the underlying mantle.
- The document discusses models of Earth's structure, including the static (geochemical) model and dynamic (geodynamic) model. The static model divides Earth into layers based on chemical composition, while the dynamic model considers physical state and mechanical properties.
- Plate tectonics theory holds that Earth's lithosphere is divided into plates that move over the asthenosphere. Plates can converge at boundaries, causing one to subduct under the other, or diverge such as at mid-ocean ridges.
- Evidence for continental drift includes matching continental margins, matching geological formations and fossil distributions across continents, and paleoclimate and paleontological indicators matching when the continents were joined in the past.
Study of plate tectonics of the earth, or plate movement, Jahangir Alam
a) Wegener’s Evidence (Continental Drift)
b) History of Plate Tectonics
c) Breakup and Appearence of Pangea
WHAT IS A PLATE?
Major continental and oceanic plates include:
Types of Earth’s Crust:
Plate tectonics (from the Late Latin tectonicus) is a scientific theory which describes the large scale motions of Earth's lithosphere.
THE DYNAMIC EARTH:
The earth is a dynamic planet, continuously changing both externally and internally. The earth’s surface is constantly being changed by endo-genetic processes resulting in volcanism and tectonism, and exogenetic processes such as erosion and deposition. These processes have been active throughout geological history. The processes that change the surface feature are normally very slow (erosion and deposition) except some catastrophic changes that occur instantaneously as in the case of volcanism or earthquakes. The interior of the earth is also in motion. Deeper inside the earth, the liquid core probably flows at a geologically rapid rate of a few tenths of mm/s. Several hypotheses attempted to explain the dynamism of the earth.
+ Horizontal movement hypothesis
+ Continental drift, displacement hypothesis
Development of the plate tectonic theory.
Plate tectonic theory arose out of the hypothesis of continental drift proposed by Alfred Wegener in 1912. He suggested that the present continents once formed a single land mass that drifted apart, thus releasing the continents from the Earth's core and likening them to "icebergs" of low density granite floating on a sea of denser basalt.
Seafloor Spreading
The first evidence that the lithospheric plates did move came with the discovery of variable magnetic field direction in rocks of differing ages.
Similar to Part1GriscomPenroseConferenceLecture (20)
Study of plate tectonics of the earth, or plate movement,
Part1GriscomPenroseConferenceLecture
1. The Case for Interpreting the ~5,000 km2 "Upland Deposits" of the U.S. Mid-Atlantic Coastal Plane as Chesapeake Bay Crater Ejecta Part I David L. Griscom impact Glass research international San Carlos, Sonora, M éxico Slightly modified and lengthened from talk presented at the: Penrose Conference “Late Eocene Earth,” Monte C ò n e ro, Italy, October 6, 2007
2. Geology of the State of Virginia Silurian and Devonian Sandstones The Chesapeake Bay Structure Southern Maryland Piedmont Coastal Plain Fall Line 50 km 50 mi This and other similar maps taken from K. Frye, Roadside Geology of Virginia (Missoula Press, 1986) Blue Ridge
3. Geology of U.S. Mid-Atlantic Coastal Plain Sandstones: Silurian Washington, DC Upper Chesapeake Bay Silurian and Devonian Sandstones Hypothetical Anticlines ~200 Million Years Ago, Now Eroded Atlantic Ocean Blue Ridge Fall Line Sand, Gravel and Clay (Soft) 350 km Ancient Metamorphic Rocks (Hard) , Devonian “ Upland Deposits”
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8. The “Upland Deposits” Gravel-Size Data and Analyses of John Schlee (1957) -6.0 -5.5 -4.5 -4.0 -5.0 -3.5 -3.0 -2.5 -2.0 Washington, DC N.B. Schlee’s gravel-size contours are labeled by the negative log to the base 2 of the observed modal sizes (phi units). Noting that the contours were more or less equally spaced in phi units, Schlee (1957) perceived a possible exponential progression. To test this notion, he took four additional sets of gravel-size data along four approximately-linear paths running generally southeasterly of the U.S. Capitol.
9. 128 mm The “Upland Deposits” Gravel-Size Data and Analyses of John Schlee (1957) Direction of the Center of the Chesapeake Bay Crater Mean Direction of Apparent Dip of the Gravel Exposures Washington, DC 32 mm 16 mm 8 mm 4 mm My Interpretation: Atmospheric size sorting of ejecta in flight. * -6.0 -5.5 -4.5 -4.0 -5.0 -3.5 -3.0 -2.5 -2.0 - - - - - Extrapolates to 128-mm cobbles at ~15 km northwest of Washington, DC – where most rocks this size are petrologically different from the upland gravels ! *Schultz, Gault (1979) 64 mm + Factor of 15!