Exam 4: Plate Tectonics

The portion of a fracture zone between two offset portions of a ridge crest is called a transform fault.

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

Young mountain belts with their associated igneous intrusions,metamorphism,and fold-thrust belts form at _______.

____ is the idea that continents move freely over Earth's surface,changing their positions relative to one another.

The San Andreas Fault is _________ in California.

Alternating positive and negative polarity magnetic anomalies in the crust form a stripe-like pattern parallel to _____.

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.

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

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

During extension in divergent plate boundaries a rift valley forms as a central ____.

This type of plate boundary the two plates can consist of ocean-ocean,ocean-continent,or continent-continent crust.

The downward plunge of cold rock at convergent boundaries accounts for the existence of _____.

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.

Divergent plate boundaries can occur where spreading occurs under a continent,for example ___.

A _____ plate boundary is where plates are moving away from each other.

The asthenosphere is a mantle zone of low seismic wave velocity that behaves in a ductile manner.

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

In plate tectonics,intense geologic activity occurs at ____.

The Vine-Matthews hypothesis provided a means to measure the rate of sea-floor spreading.

Plumes form ______ that are related to areas of active volcanism such as Iceland,Yellowstone and Hawaii.