Focus: Plate Tectonics and Ice Cores Earth History: Day 15 Focus: Plate Tectonics and Ice Cores 11/29/17 Pick up a copy of the notes from the front lab table. Science starter: Copy and answer. Marine fossils have been found at the tops of mountains. How can this be explained?

Good morning! *Next D.C. Payment due January 26th.

Plan for the Day 1.Lesson on plate tectonics and boundaries Notes Video clips Web quest 2.Discuss ice cores

Homework Finish the Plate Tectonics web quest.

Alfred Wegener and his Continental Drift Theory Continental drift describes one of the earliest ways geologists thought continents moved over time. Today, the theory of continental drift has been replaced by the science of plate tectonics.    The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other. He called this movement continental drift.  Wegener was convinced that all of Earth’s continents were once part of an enormous, single landmass called Pangaea.  https://www.nationalgeographic.org/encyclopedia/continental-drift/

Evidence For His Theory A. Puzzle-like fit of the continents: South America and Africa would fit remarkably well, shoreline to shoreline – other continents, too. B. The Rock Record Geologic features (rock types and mountains) match along the edges of continents that may have once been connected such as the Appalachian mountains in the US and the Caledonian mountains in England & Norway.

Evidence For His Theory A. ____________ fit of the ___________: South America and _________ would _____remarkably well, shoreline to shoreline – other _____________, too. B. The Rock Record ___________ features (____ types and ___________) match along the _________of continents that may have once been ____________ such as the Appalachian mountains in the US and the Caledonian mountains in England & Norway.

Evidence for his theory continued C. The Fossil Record Matching plant and animal fossils are found in areas that may have been connected in the past but today are separated by an ocean

Evidence for his theory continued C. The __________ Record ______________ plant and animal ___________ are found in areas that may have been __________ in the past but today are ____________ by an ocean.

Evidence for His Theory Continued D. The Climate Record Coal deposits have been found in Antarctica indicating that Antarctica must have been in a more tropical area of our planet at one time in the past. (Coal forms from the remains of dead swamp plants-no swamps in Antarctica today) AND fossils of tropical plants have been found in areas with very cold climates today, suggesting that the continents may have moved through different climate zones as Pangaea broke apart.

Evidence for His Theory Continued D. The ____________ Record _____ __________ have been found in _____________ indicating that Antarctica must have been in a more ___________ area of our planet at one time in the _________(Coal forms from the remains of dead ________ plants-no swamps in Antarctica today) AND _________ of _____________ plants have been found in areas with very ________ climates today, suggesting that the __________ may have _________ through different __________ ________ as Pangaea broke apart.

When ALFRED WEGENER proposed his THEORY of CONTINENTAL DRIFT, he had solid evidence to support the idea that the continents had once been connected. The problem was that he could NOT explain HOW CONTINENTS COULD MOVE. Therefore, his theory was not widely accepted. Then, science figured out HOW this could happen! Do you remember HOW?

So… what came first…the theory of continental drift or the science of plate tectonics? The theory of continental drift came first…the evidence. The theory of plate tectonics came later and explained the HOW of it all!!!

Let’s begin discussing plate tectonics.

What are the causes and effects of tectonic plate movement? E.Q. What are the causes and effects of tectonic plate movement?

Let’s watch a short video about continental drift and plate tectonics. http://www.teachersdomain.org/asset/ess05_vid_plateintro/

A term you better know!!!!! Lithosphere: the rigid outer shell of the planet that we call the crust. “Lith” means “stone”. All continents and oceans are located on plates of lithosphere. When we look at mountains or other land features, we are looking at lithosphere. Forces beneath the lithosphere cause it to move around.

A term you better know!!!!! _____________:the rigid _______ ________ of the planet that we call the _______. “Lith” means “_______”. All continents and _______ are located on ___________ of lithosphere. When we look at mountains or other land features, we are looking at lithosphere. Forces ___________ the lithosphere cause it to ________ __________.

Convection currents in the mantle . Why do the plates move? Convection currents in the mantle a. Due to tremendous heat, most rock in the mantle is molten (thick liquid). b. Crust (lithosphere) moves around on top of hot, flowing rock. c. Inside the Earth, hot, low-density magma rises from the core toward the crust. Magma cools beneath the crust, becomes more dense, and sinks back into the mantle. This rising and sinking creates circular currents called convection currents. These currents push and pull tectonic plates around.

Convection currents in the mantle . Why do the plates move? Convection currents in the mantle a. Due to tremendous _______, most rock in the ________ is _________ (thick liquid). b. Crust (____________) moves around on top of hot, _____________ rock. c. Inside the Earth, hot, low-density magma ___________from the _______ toward the________. Magma cools __________the crust, becomes more ___________, and __________ back into the mantle. This _________and sinking creates ____________ currents called ______________ ___________. These currents ________ and _______ tectonic _____________around.

. Why do the plates move? (cont.) 2. At subduction zones (convergent), huge “slabs” of oceanic lithosphere (crust) are being pulled back down into asthenosphere (mantle) where they are being destroyed and recycled. This is called “slab pull”. 3. Meanwhile, at mid-ocean ridges, oceanic lithosphere is being pushed apart as magma forces its way up through the ocean floor, cools, and hardens into new oceanic lithosphere (crust). This is called “ridge push”.

. Why do the plates move? (cont.) 2. At ______________ zones (convergent), huge “__________” of oceanic lithosphere (crust) are being ___________ back _______ into asthenosphere (________) where they are being destroyed and recycled. This is called “________ __________”. 3. Meanwhile, at _____-_______ _________, oceanic lithosphere is being ____________ apart as ________ forces its way up through the ocean _______, cools, and hardens into new oceanic ______________(crust). This is called “________ _____________.”

Cool Ridge Push Convection Currents

Cool Ridge Push Convection Currents

Let’s watch a video of these 3 forces in action. Earth's interior animation of convection and plate tectonics

Results of Plate Movement 1. Changes in the shape of Earth’s crust over time…Formation of Earth’s features, such as mountains, volcanoes, and deep sea trenches. 2. Changes in climate due to the movement of crustal plates through different climate zones over time causing ice caps to increase/decrease, volume of oceans to increase/decrease, & organisms to live/die 3. Changes in sea levels as volume of oceans & height of land changes over time (result of #2 above) 4. Evolution/adaptations of living organisms as plates move through various types of climate zones

Results of Plate Movement 1._________ in the shape of Earth’s ______over time…Formation of Earth’s _______, such as __________, volcanoes, and deep sea ________. 2. -Changes in ________ due to the movement of crustal plates through different _______ zones over time causing ice caps to _______/decrease, volume of _______ to increase/________, & organisms to ____________

Results of Plate Movement 3. -Changes in _____ ______as volume of oceans & height of ______changes over time (result of #2 above) 4. - _________/___________ of living organisms as plates move through various types of ________ zones

Plate Movement Let’s review plate boundaries and effects of their movements.

Plate Movement Let’s review plate boundaries and effects of their movements.

Convergent Boundaries: Oceanic-continental convergence: What features form at these boundaries? Subduction zone

Convergent Boundaries: Example of Oceanic-continental convergence: Deep-ocean trench Deep-ocean trench

Convergent Boundaries: Oceanic-oceanic convergence: What features form at these boundaries? Subduction zone

Convergent Boundaries: An example of Oceanic-oceanic convergence: The Mariana Trench is over 30,000 ft. deep.

Convergent Boundaries: The Ring of Fire - an example of oceanic-continental and oceanic-oceanic convergence: Divergent boundary-as plates move apart here, they crash into other plates elsewhere-convergence

Convergent Boundaries: Continental-continental convergence (also called Collisional) What features form at these boundaries?

Convergent Boundaries: Continental-continental convergence (also called Collisional)

Divergent Boundaries: Oceanic: What features form at these boundaries? Rift Valley

Divergent Boundaries: Oceanic- an example:

Oceanic divergent-an example - Iceland

Divergent Boundaries: Continental: Rift Valley Ridges What features form at these boundaries?

Divergent Boundaries: Continental – an example: Great Rift Valley in Africa

Transform Boundaries: Oceanic or Continental: What events are most closely related to movements at these boundaries?

Transform Boundaries: Earthquakes Oceanic or Continental: San Andreas Fault How are transform boundaries different from convergent and divergent?

But, what about how the atmosphere has changed? Fossils _______ give us clues about the existence, activities, and possibly, the changes that may have occurred in living things throughout Earth’s history. _______ give us clues about changes in Earth’s geologic features throughout Earth’s history. But, what about how the atmosphere has changed? Rocks

Ice cores- Yes, we’ve talked about them, but we need to take a few notes, too. Def. Cylinders of ice drilled from ice caps and glaciers. A.D. 1 –Deeper ice is older. A.D. 2 -The ice may contain gases, volcanic ash, and even traces of rare elements. A.D. 3 -This information gives clues about how Earth’s atmosphere and climates have changed throughout its history.

Ice cores Def. Cylinders of ____ drilled from ice caps and _________. A.D. 1 –______ ice is _____. A.D. 2 -The ice may contain _______, volcanic _____, and even traces of rare ________. A.D. 3 -This information gives _____ about how Earth’s ________ and ________ have _________ throughout its history.

Whatever gases (carbon dioxide, oxygen, methane, etc Whatever gases (carbon dioxide, oxygen, methane, etc.) and solids (volcanic ash, dust, salts) are in the air are also going to be in the water. There is no invisible barrier to keep them out of bodies of water.

When water freezes, those gases and solids are trapped…frozen in time When water freezes, those gases and solids are trapped…frozen in time. Ice core samples can give scientists an idea of how the atmosphere has changed by analyzing the substances found in the core samples. Was there a period of great volcanic activity across the Earth? Was there a period of time when our air was not so oxygen-rich?

Points to Remember 1. The processes responsible for biological, geological, and atmospheric changes we see on Earth today (volcanoes, weathering, erosion, flooding, earthquakes, plate movements, rising sea levels) have occurred throughout Earth’s history. Some of these can be results of human activity and can be placed, to some extent, under human control. List and explain at least 3 examples. 2. Both natural processes & human activities result in environmental challenges such as global climate change. A. How will our use of nonrenewable energy potentially impact the future of this planet?(consider events listed above) B. What might future generations find in ice cores from our time?