Geology: Continental Drift and Plate Tectonics

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Questions and Answers

What statement best describes Wegener's idea of continental drift?

Continents were formerly in different positions on the Earth and have shifted to their present locations over time.

How was the fossil record of ancient life used to support Wegener's hypothesis about Pangaea?

Fossils of identical organisms were found on several continents, indicating the continents were once joined.

What would the climate have been at the time coal deposits were formed in the location indicated?

The climate would have been a warm, humid climate near the Equator.

Why might the coastlines of once-joined continents such as South America and Africa not fit together nicely?

The continental shelves are the edges of the continent. Signup and view all the answers

What evidence supports that the glaciers on the southern continents were once part of a single, massive ice sheet?

Striations Signup and view all the answers

Which scientist developed the idea of Continental Drift?

Alfred Wegener Signup and view all the answers

What is the name of the supercontinent proposed by Alfred Wegener?

Pangaea Signup and view all the answers

Which statement about the theory of plate tectonics is correct?

The rigid lithosphere plates overlay the hotter and weaker asthenosphere. Signup and view all the answers

Which tectonic boundary results when two tectonic plates pull apart from each other?

Divergent boundaries Signup and view all the answers

What features allow for the offset of divergent boundaries?

Transform faults Signup and view all the answers

Which feature would you expect to find in East Africa where crustal rifting is currently occurring?

Normal Faults, long-wide valleys, and lava flows Signup and view all the answers

What is convection?

Convection is a cycle of moving material formed by the rise of less-dense material and the sinking of denser material. Signup and view all the answers

What accounts for most tectonic plate motion?

Forces at subduction zones account for most tectonic plate motion. Signup and view all the answers

What is the relationship between temperature and density?

In general, warmer materials are less dense, and colder materials are more dense. Signup and view all the answers

Which term best characterizes up-welling in the Asthenosphere?

Diffuse Signup and view all the answers

What is a plume?

A plume is a zone of up-welling material originating at the outer core-mantle boundary. Signup and view all the answers

What features at the surface provide evidence of plumes?

Hot spots provide evidence of plumes. Signup and view all the answers

How do plates move at divergent plate boundaries?

Plates move apart at divergent plate boundaries. Signup and view all the answers

How do plates move at convergent plate boundaries?

Plates move toward one another at convergent plate boundaries. Signup and view all the answers

How do plates move at transform plate boundaries?

Plates slide past one another at transform plate boundaries. Signup and view all the answers

Study Notes

Continental Drift and Pangaea

Alfred Wegener proposed the theory of Continental Drift, claiming continents were once part of the supercontinent Pangaea.
Fossil evidence supports this theory, with identical organisms found across separated continents, indicating they were once connected.
Late Paleozoic sedimentary rocks containing coal seams suggest a warm, humid climate near the Equator, aligning with Pangaea's past location.

Plate Tectonics and Boundaries

The lithosphere consists of rigid plates that float over the weaker asthenosphere.
Tectonic plates pull apart at divergent boundaries due to tensional stress, creating features such as mid-ocean ridges.
Transform faults allow lateral offsets along divergent boundaries, resulting in segmented ridges.

Rifting and Faults

East Africa experiences crustal rifting, evident through normal faults, widened valleys, and lava flows indicating tensional stress.

Convection and Plate Motion

Convection refers to the movement of material driven by buoyancy differences, where less-dense materials rise and denser materials sink.
Subduction zones are primary drivers of tectonic plate motion, facilitating the movement of plates.

Density and Temperature Relationships

Warmer materials tend to be less dense, while colder materials are more dense, influencing geological processes.

Geological Features

Plumes are up-welling zones of material rising from the outer core-mantle boundary, often indicated by the presence of hot spots.
Divergent boundaries result in plates moving apart, while convergent boundaries have plates moving toward one another. Transform boundaries are characterized by lateral sliding of plates.
Earthquakes and volcanic activity predominantly occur at tectonic plate boundaries due to the movement and interaction of the plates.

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Description

Explore the fascinating concepts of continental drift and plate tectonics in this quiz. Learn about Alfred Wegener's theory of Pangaea and the evidence supporting it, as well as the dynamics of tectonic plates and their boundaries. Test your knowledge on rifting, faults, and the processes that shape our planet.