Plate Tectonics Earth Science

Theory of Plate Tectonics

The lithosphere is broken into Tectonic Plates

• The lithosphere is made from the crust and the uppermost part of the mantle

• The lithosphere is rigid, brittle rock

• These plates float on the asthenosphere

Pangea

• The super continent that Alfred Wegener described in his theory of Continental Drift

How do the plates ACTUALLY MOVE?

• Convection currents in the asthenosphere drive the movement of lithospheric plates

How does a convection cell occur?

• Hot magma in the asthenosphere begins to rise, similar to the way hot air rises.

• As it rises to the top of the asthenosphere, it cools and becomes more dense.

• This cooler, dense magma then sinks again. As it sinks, it gets warmer, until the process begins again

• This movement of magma is what drives the plates to move.

Multiple Choice

Tectonic plates consist of

• continental crust

• mesospheric crust

• both continental and oceanic crust

• oceanic crust

Multiple Choice

The idea that the continents were once part of a single landmass that broke apart and

moved is

• Continental Drift

• Tectonic Plates

• Transform

Multiple Choice

The region where two lithospheric plates meet

• Continental Drift

• Plate tectonics

• Plate Boundaries

Multiple Choice

The scientist who developed the big idea called "sea-floor spreading"

• Alfred Wedgener

• Harry Hess

• Edward Dutton

• Ortelius

Multiple Choice

Pangaea was an ancient supercontinent made up of...

• America, Greenland, and Europe

• Antarctica, India, and America

• all of Earth’s continents

• South Africa, India, Australia, and South America

Multiple Choice

Why did no one believe Wegener's thoery that the continents were once together?

• He could not explain HOW the continents moved

• He didn't have evidence

• His data was wrong

• He didn't use the right technology to gather data

Multiple Choice

The movement of the tectonic plates is caused by

• the rotation of the Earth

• convection currents in the Asthenosphere

• the gravity of the iron-nickel core

• the Moho discontinuity

Multiple Choice

Which layer of the Earth consists of tectonic plates?

• asthenosphere

• mantle

• mesosphere

• lithosphere

Multiple Choice

Tectonic plates “float” on

• the lithosphere

• the mantle

• the ocean

• the asthenosphere

Multiple Choice

The fact that similar fossils are found on both sides of the ocean is evidence of

• magnetic reversal

• global positioning

• continental drift

• oceanic drift