theory of plate tectonics assignment quizlet

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Plate Tectonics

11th -  12th  , 17.1k plays, 9th -  12th  , 12.8k plays, plate boundaries, 6th -  7th  , tectonic plates, 44.5k plays, 6th -  8th  , plate tectonics, earthquakes, volcanoes.

9th - 12th grade

20 questions

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What is the correct order (starting from the surface) of Earth’s layers?

crust, outer core, inner core, mantle

mantle, outer core, inner core, crust

crust, mantle, outer core, inner core

outer core, inner core, crust, mantle

In sea-floor spreading, molten material rises from the mantle and erupts

along the edges of all the continents.

along mid-ocean ridges.

in deep-ocean trenches.

at the north and south poles.

The process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle is known as _______

convection.

continental drift.

subduction.

conduction.

Most geologists think that the movement of Earth’s plates is caused by _______

The geological theory of _______ states that pieces of Earth’s lithosphere are in constant, slow motion.

plate tectonics

deep-ocean trenches

sea-floor spreading

A place where two plates slip past each other, moving in opposite directions, is known as a _______

transform boundary

divergent boundary.

convergent boundary.

rift valley.

Scientists think that convection currents flow in Earth’s

continents.

lithosphere.

inner core.

The place where two plates come together is known as a _______

transform boundary.

Below is a picture of sea-floor spreading. How are the ocean crusts moving?

No movement

The San Andreas Fault in California is known as an active earthquake area. What type of

boundary is it?

Sea Floor Spreading

• 12. Multiple Choice Edit 30 seconds 1 pt How is it possible for new crust to be formed without increasing the surface area of the Earth? Crust is destroyed at the same time it is created New crust is underwater where it sinks New crust breaks more easily than old crust
• 13. Multiple Choice Edit 1 minute 1 pt This layer of Earth is the thickest part crust outer core mantle inner core
• 14. Multiple Choice Edit 30 seconds 1 pt What are the two types of crust continental and oceanic ocean and upper lower and upper pizza and subway
• 15. Multiple Choice Edit 1 minute 1 pt The Himalayas in Asia are an example of what type of plate boundary? divergent continent-to-continent convergent ocean-to-continent convergent transform
• 20. Multiple Choice Edit 30 seconds 1 pt Mountains form from ... plates sliding past one another collision of plates plates moving away from each other

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Plate Tectonics

Theory of plate tectonics, lesson objectives.

• Describe what a plate is and how scientists can recognize its edges.
• Explain how mantle convection moves lithospheric plates.
• List the three types of boundaries. Are they prone to earthquakes or volcanoes?
• Describe how plate tectonics processes lead to changes in Earth’s surface features.
• continental arc
• continental rifting
• convergent plate boundary
• divergent plate boundary
• intraplate activity
• plate boundary
• plate tectonics
• subduction zone
• supercontinent cycle
• transform fault
• transform plate boundary

Introduction

When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around Earth’s surface. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics.

Continental drift and the mechanism of seafloor spreading create plate tectonics: http://video.yahoo.com/watch/1595682/5390276 .

Earth’s Tectonic Plates

Seafloor and continents move around on Earth’s surface, but what is actually moving? What portion of the Earth makes up the “plates” in plate tectonics? This question was also answered because of technology developed during war times – in this case, the Cold War. The plates are made up of the lithosphere.

During the 1950s and early 1960s, scientists set up seismograph networks to see if enemy nations were testing atomic bombs. These seismographs also recorded all of the earthquakes around the planet. The seismic records could be used to locate an earthquake’s epicenter , the point on Earth’s surface directly above the place where the earthquake occurs.

Earthquake epicenters outline the plates. Mid-ocean ridges, trenches, and large faults mark the edges of the plates, and this is where earthquakes occur ( Figure below ).

Divergent Plate Boundaries

Plates move apart at mid-ocean ridges where new seafloor forms. Between the two plates is a rift valley. Lava flows at the surface cool rapidly to become basalt, but deeper in the crust, magma cools more slowly to form gabbro. So the entire ridge system is made up of igneous rock that is either extrusive or intrusive. Earthquakes are common at mid-ocean ridges since the movement of magma and oceanic crust results in crustal shaking. The vast majority of mid-ocean ridges are located deep below the sea ( Figure below ).

Earth’s Changing Surface

Geologists know that Wegener was right because the movements of continents explain so much about the geology we see. Most of the geologic activity that we see on the planet today is because of the interactions of the moving plates.

In the map of North America ( Figure below ), where are the mountain ranges located? Using what you have learned about plate tectonics, try to answer the following questions:

Plate boundaries

• What are the three types of plate boundaries and what type of geologic activity is found at each?
• As a geologist, you come across a landscape with a massive fault zone that produces a lot of large earthquakes but has no volcanoes. What type of plate boundary is this? What are the movements of plates there? Where is this type of boundary found in California?
• Next you find a chain of volcanoes along a coast on land, not too far inland from the ocean. The region experiences frequent large earthquakes. What type of plate boundary is this? What types of plates are involved? Where is this type of boundary found in California?
• What is the driving force behind the movement of lithospheric plates on the Earth’s surface? About how fast do the plates move?
• How does the theory of plate tectonics explain the locations of volcanoes, earthquakes, and mountain belts on Earth?
• What causes earthquakes and at what types of plate boundaries are earthquakes common? Explain.
• Thinking about the different types of plate boundaries, where do mountain ranges that do not include volcanoes occur and why?
• Why are there no volcanoes along transform plate boundaries? At continent-continent convergent plate boundaries?

Points to Consider

• On the map in Figure above , the arrows show the directions that the plates are going. The Atlantic has a mid-ocean ridge, where seafloor spreading is taking place. The Pacific Ocean has many deep sea trenches, where subduction is taking place. What is the future of the Atlantic plate? What is the future of the Pacific plate?
• Using your hands and words, explain to someone how plate tectonics works. Be sure you describe how continents drift and how seafloor spreading provides a mechanism for continental movement.
• Now that you know about plate tectonics, where do you think would be a safe place to live if you wanted to avoid volcanic eruptions and earthquakes?
• Earth Science for High School. Provided by : CK-12. Located at : http://www.ck12.org/book/CK-12-Earth-Science-For-High-School/ . License : CC BY-NC: Attribution-NonCommercial