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Southern California Geology


Geologic Setting of the San Gabriel Mountains, Transverse Ranges Province

Crystalline Basement Rocks

Most of the crystalline basement rocks that make up the San Gabriel Mountains occur in two packages that are separated by a major geologic structure--the Vincent Thrust . The thrust apparently occurs throughout most of the range, and is a low-angle tectonic dislocation (fault or movement zone) that separates upper-plate rocks above the dislocation from lower-plate rocks below it. Fault movement along this low-angle zone may have been on the order of several tens of kilometers, and is responsible for bringing together the two distinctive packages of rock in the lower and upper plates.

Table of Contents, Crystalline Rocks

Vincent Thrust Rocks in the lower plate of the Vincent Thrust

Rocks in the upper Plate of the Vincent Thrust

Western and central San Gabriel Mountains

Eastern San Gabriel Mountains

Rocks in southeastern San Gabriel Mountains

Continue to Vincent Thrust
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This site last updated September 3, 2004 (ps)

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