Exam 4: The Way the Earth Works: Plate Tectonics

The pulling forces that produce the most rapid plate velocities are concentrated at ____________.

As lithosphere cools to the sides of a mid-ocean ridge,it begins to ____________.

A guyot is ____________.

The number of lithospheric plates on the Earth has been variable through geologic time.Hundreds of millions of years ago,there were plates that no longer exist today.

Segments of the mid-ocean ridge system are offset.Between the offset segments we observe ____________.

At a convergent plate boundary (shown below),two opposed plates ____________.

A volcanic island arc forms when _______________.

Mid-ocean ridges are ____________.

Hot spots can occur ____________.

Under the theory of plate tectonics,the plates themselves are ____________.

The lithosphere of the Earth is generally thickest at and near ____________ plate boundaries.

The Wadati-Benioff zone extends down within the mantle to a maximum depth of ____________.

The thickness of oceanic lithosphere is ____________.

At a transform plate boundary (shown below),two opposed plates ____________.

The San Andreas Fault zone in southern California is an example of a ____________ plate boundary.

Consult the figure below.Hot-spot tracks result from moving _____________.

All portions of the mid-ocean ridge system have a well-defined axial trough (central rift).

At a subduction zone,the downgoing (subducting)plate ____________.

The lithosphere of the Earth is generally thinnest at and near ____________ plate boundaries.

Oceanic lithosphere thickens away from the mid-ocean ridge primarily due to ____________.