Alfred Wegener observed that which two continents looked like they fit together?

At this kind of plate boundary, tectonic plates pull away from each other

At what kind of plate boundary does subduction happen?

When tectonic plates pull apart underwater, this feature is created

When liquid or gas is heated, it becomes less dense, and this happens

The hottest, innermost layers of the Earth, are called what?

At this kind of plate boundary, tectonic plates move toward each other

At what kind of plate boundary is new crust created?

When an oceanic plate subducts under another oceanic plate, this feature is created on the overlying plate

The flow of material in the Earth's mantle drags tectonic plates around. What is this flow called?

The name for the super continent when all land was connected

This kind of crust is dense, and rides low on the mantle

What kind of plate boundary experiences earthquakes, but has no specific geologic features?

When tectonic plates pull apart on land, this feature is created

The leading edge of a subducting plate may help pull the rest of the plate behind it. What is this hypothesis called?

Continental Drift was a ______________, but Plate Tectonics is a _______________.

This kind of crust can be very old (several billion years)

What geologic feature will be found on the ocean floor at a subduction zone?

This country sits on top of the Mid-Atlantic Ridge

Where is the newest crust on the Earth found?

The Earth's _____________ is broken up into plates, which float on the ______________.

This kind of tectonic plate boundary runs through southern California

The western part of the United States has strange features. It was attached to the continent by subduction and is called what?

This volcanic arc rises in the Pacific Northwest

When mantle material cools off, what happens to it?