Theory of Plate Tectonics: Assignments and Quiz

The seafloor near the east coast of the US is about how old? Compared to all of Earth's oceanic crust, how old is the seafloor just west of Mexico? Which coastline of South America is nearest to the oldest seafloor? The mid-ocean ridge in the middle of the Atlantic ocean has seafloor that is how old?

1. 180 million years. 2. Very young. 3. Eastern. 4. 0-10 million years

Label A: Label B: Label C: Label D:

1. Australian plate 2. South American Plate 3. African plate 4. Antarctic plate

Mid-ocean ridges and rift valleys are important features generated along a _______ boundary. The San Andreas fault is a _______ boundary where plates slide horizontally past each other, creating numerous earthquakes. An ocean trench is a feature formed as one plate subducts below another along a ______ boundary.

1. Divergent 2. Transform 3. Convergent

Label A: Label B: Label C:

1. Oceanic-oceanic 2. Oceanic-continental 3. Continental-continental

Subduction zones mainly affect people who are living in the _______. Earthquakes along the subduction zones near Sumatra and Chile are some of the _____ in the world. At a subduction zone, plates and faults can shift rapidly, forcefully displacing the ocean waters above. This can result in ______ being generated, which can affect coastlines thousands of miles away.

1. Pacific 2. Strongest 3. Tsunamis

One of the large, fairly rigid blocks into which Earth's lithosphere is broken. A long chain of mountains on the ocean floor where seafloor spreading is occurring. The process along a convergent boundary where one plate sinks under another plate. A plate boundary where two plates slide horizontally past each other. A long, narrow valley formed where two tectonic plates split apart

1. Tectonic plate 2. Mid-Ocean ridge 3. Subduction 4. Transform boundary 5. Rift valley

The theory of plate tectonics includes ______ types of plate boundaries. A _______ boundary is formed when plates move away from each other. Where plates move toward each other, and one plate sinks below another, a _______ boundary is formed. Where two plates slide horizontally past each other, a ______ boundary is form. Of these boundary types, the one most important for subduction and the recycling of lithosphere back into the mantle is the _____ boundary

1. Three 2. Divergent 3. Convergent 4. Transform 5. Convergent

Which features/processes would result from plate movement? Check all that apply.

1. volcanoes and earthquakes 3. mountain building 4. trench formation

Which processes are caused by convection currents in the mantle? Check all that apply.

2. Ridge push 4. Slab pull 6. Subduction

Which is a type of tectonic plate boundary?

A. Divergent

Elias is driving through the southwest part of the US on a road trip, and gets out of the car to go hiking. While hiking, he notes a very long channel running for miles in one direction. There are no distinct mountains nearby, and he is very far from the ocean. At lunch, the locals tell him there are lots of earthquakes in the area. He also thinks he sees an old road that used to cross the channel, but looks like it has been shifted apart somehow. He recalls what he learned about plate tectonics in class. Given these clues, what type of plate boundary could Elias possibly be standing on or near?

A. Transform

Marina is creating a flow chart of the mechanics of mantle convection and how it relates to tectonic plate movement. Which words should Marina place in each blank of the flow chart?

A. asthenosphere, ridge push, subduct

Identify the plate being pointed out by the arrow.

D. Pacific plate

Convection currents in the Earth's mantle are responsible for the movement of tectonic plates. As shown in the diagram, heat from the Earth's core is the driving force that moves magma in a circular motion called "cells." How is this circular motion achieved?

D. Hot magma rises and pushes up toward the lithosphere, and as it cools it cycles back down toward the core to be heated again.

What process, driven by heat generated from within the Earth's core, occurs in the mantle and is a primary cause of plate tectonics?

B. Mantle convection

Samuel puts a pot of water on the stove to boil and remembers when his teacher taught the class about convection, which is fluid movement driven by heat. Samuel recalls that convection in the Earth's mantle involves the movement of

B. Molten materials

In which direction is the Pacific Plate moving in relation to the North American Plate?

B. Northwest

Sylvia is designing a new shopping center to be built near a transform boundary. Aware of the dangers of geologic activity along a transform boundary, what would be the best safety feature for Sylvia's design?

B. Shorter buildings designed with some flexibility, enabling them to move without falling apart during an earthquake.

Carlos is looking at a picture of a convergent boundary on which a volcanic arc and a trench are identified. Which type of convergent boundary is Carlos looking at?

B. an oceanic-arctic convergent boundary

The continents of Africa and South America used to "fit together" like puzzle pieces. About how far back in time would you have to go to find the formation of the Atlantic ocean?

C. 200 Million years

Where are most earthquakes found?

C. Along the plate boundaries

Which phrase describes the movement of the continents?

C. Coming together and moving apart.

What could be a possible explanation why tectonic plates do not all move in the same direction?

C. The magma moves in "cells," which circulate in different directions, moving the plates in more than one direction.

The tectonic plates of the lithosphere move across Earth's surface. What is the approximate rate of plate movement?

D. A few centimeters each year

Based upon the mechanics of mantle convection, which feature will most likely be formed at the blue arrow, and through which mechanism?

D. A mid-ocean ridge will be formed by ridge push.

Marina has been onboard the research vessel Gustavo, off the coast of Chile, for several weeks now. She is measuring the depth of a very deep trench in the ocean that runs parallel to the coastline. In the distance, she notes a great mountain range on the mainland. Suddenly, she is notified that a submarine earthquake just occurred below the trench, generating a tsunami. As Marina puts on her lifejacket, she recalls the type of plate boundary nearby that led to the trench formation. Based on the description given, what type of plate boundary is near the area Marina has been studying?

D. Convergent

Identify the large brown tectonic plate and whether it is oceanic or continental.

D. North American, continental