physical geology_ lesson 1-3

When did geologists develop the theory of plate tectonics?

in the 1960's

The supercontinent in the Continental Drift hypothesis was called ___________

pangea

________________ is thick (30 - 75 km), old (up to 4,400,000,000 years), composed of felsic (granitic) silicates, light (~2.7 g/cm3), and is highly deformed by folding.

Continental crust

In which layer of the Earth does the convection necessary for plate motion occur?

Mantle

What property of the crust allowed it to form as the exterior of Earth?

Materials that make up the crust are less dense and rose to the top

If the temperature in the Earth generally increases with depth, how is it possible that the Inner Core is a solid?

The pressures in the core are immense and keep it in a solid state in spite of the temperature

The Red Sea is an example of:

initial rifting of a continent

The only layer of the Earth that is a liquid is the

outer crust

Approximately how old is the oldest oceanic crust?

180,000,000 years

Which scientist developed the Continental Drift hypothesis?

Alfred Wegener

A ________ is a geographic low marking the location where oceanic lithosphere descends into the mantle.

Deep-Ocean Trench

Which type of convergence will result in a continental volcanic arc?

Oceanic-Continental

What happens when an oceanic plate converges with a continental plate?

The denser oceanic plate slides under the less dense continental plate.

What was the main reason the Continental Drift hypothesis was rejected?

The scientist who proposed it could not provide a mechanism for the movement of the continents

The lithosphere is made up of the upper-most mantle and the

crust

The thickness of ocean sediments that are close to a mid-ocean ridge is __________ the thickness of ocean sediments that are far from mid-ocean ridges.

less than

Which is the thinnest physical (mechanical) layer of the Earth?

lithosphere

The Hawaiian Islands are thought to have been formed at a ____________.

mantle plume/ hot spot

A divergent boundary is a boundary between two plates that __________.

move away from each other

What provides us with the most information about the interior of the Earth?

seismic energy (earthquake) waves

Divergent boundaries are places where:

shallow earthquakes occur, basaltic magma erupts, and new ocean lithosphere is created

The San Andreas Fault represents a:

transform boundary

Rocks close to mid-ocean ridges are __________ rocks far from mid-ocean ridges.

younger than

What is the polarity of a magnetic field that has the same polarity as the present magnetic field?

a normal polarity

__________________ are scratches or gouges cut into bedrock by glacial abrasion.

striations

Harry Hess' theory of __________ explained how ocean crust is generated and destroyed

Seafloor Spreading

What is the definition of the asthenosphere?

Solid, but "plastic" region of the upper mantle

At a ________, one colliding plate will be forced beneath another because of differences in density.

Subduction Zone

13.82 billion years ago, the Big Bang created the _____________ from a point source.

Universe

How will the age and temperature of the subducting plate affect its angle of descent?

Younger and warmer plates will have a shallow angle of descent