Chapter 2

The oceanic crust is -------than the continental crust

sits lower in the mantle is more dense is thinner

What causes tectonics plates to move?

Convection in the Mantle

The Himilayan Mountains

Convergent Boundary

Why was Alfred Wegner's Theory of continental drift not accepted?

He could not explain what caused the continents to move.

Which of the following is NOT true about a hot spot?

Hot spots are primarily located near plate boundaries

Oceanic crust is formed at __________ boundaries and destroyed at ___________ boundaries.

divergent ; convergent

Approximately how fast do tectonic plates move?

1-15 cm/yr

The San Andreas Fault

Transform Boundary

Oceanic crust is primarily composed of __________ while continental crust is composed of ____________.

basalt ; granite

Magnetic minerals within rock which have an inclination of 90 degrees (are perpendicular to the surface) indicate that the rock formed ____________ .

At the magnetic pole

The Red Sea

Divergent Boundary

ectonic plates are part of the ____________ and float on the _____________ .

Lithosphere ; Asthenosphere

Paleomagnetic stripes on the ocean floor run parallel to _____________ .

Mid Ocean Ridges

Why isn't there much ocean crust older than 180 million years old?

Old ocean crust becomes cold and dense and eventually subducts back into the mantle

Which of the following did Alfred Wegner NOT use as evidence for his theory of continental drift?

Paleomagnetic stripes on the ocean floor

Divergent Boundary

Plates Spreading Apart

Converget Boundary

Plates moving together and colliding

Transform Boundary

Plates sliding next to each other side by side