Exam 19: Plate Tectonics

Evidence in support of continental drift includes ____.

These plate boundaries are marked by shallow-focus earthquakes in a narrow zone for a single fault or in a broad zone for a group of parallel faults.

Continental drift incorporated sea floor spreading into the new concept of plate tectonics.

Suture zones in continents mark old sites of mantle plumes.

Recent studies using seismic tomography indicates that whole mantle convection is the best model.

Pangea initially separated into two parts, the southern part is called ____.

All transform faults connect two ridge segments.

Lithosphere is remarkably constant in thickness across ocean basins.

Magma heated by ocean-continent convergence may form a(n) _____ such as the Aleutian Islands.

As a descending plate reaches depths of about 100 km, magma is generated in the overlying asthenosphere.

Harry Hess proposed that the _______.

Continental drift is the hypothesis that the sea floor forms at the crest of the mid-oceanic ridge, then moves horizontally away from the ridge crest.

A tectonic plate is always made up of a combination of continental and oceanic crust.

The most common type of transform faults offset oceanic ____.

A divergent boundary on the sea floor is associated with ______.

The isotopic ages of Hawaiian Island basalts increase regularly to the ____.

The basic idea of ______ is that the Earth's surface is divided into a few large plates that move slowly relative to one another.

_______ proposed an explanation for magnetic anomalies.

The Peru-Chile trench is moving over the ________ Plate as South America moves west.

In plate tectonics, intense geologic activity occurs at ____.