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A Study of Miocene Vulcanism in Southern California


Bonillas, Ygnacio, III (1935) A Study of Miocene Vulcanism in Southern California. Master's thesis, California Institute of Technology. doi:10.7907/BZRE-N110.


The widespread Miocene volcanic rocks of Southern California represent at least four distinct epochs of activity. Lower Miocene vulcanism is represented by the basic hypersthene andesite flows north of Soledad Canyon and east of Mint Canyon. Lower middle Miocene flows are found in the Santa Monica Mountains and the Verdugo Hills; they are olivine poor basalts. Upper middle Miocene intrusives are abundant in the Santa Monica Mountains; they are usually olivine rich basalts. Upper Miocene siliceous andesite and dacite flows occur in the San Jose Hills. It is found that the distinction between the lower, middle, and upper Miocene volcanics is sharp, but that the two epochs of middle Miocene vulcanism resulted in quite similar rooks. The latter rocks are the most abundant in this region, and volcanics of lower or upper Miocene age are rare.

Item Type:Thesis (Master's thesis)
Subject Keywords:Geology
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Unknown, Unknown
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1935
Record Number:CaltechTHESIS:01122010-091637518
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5513
Deposited By: Tony Diaz
Deposited On:15 Jan 2010 20:17
Last Modified:03 Oct 2019 23:44

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