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Geology of a part of the southwestern portion of the San Gabriel Mountains

Citation

Cogen, William Maurice (1931) Geology of a part of the southwestern portion of the San Gabriel Mountains. Bachelor's thesis, California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:12142009-144520602

Abstract

The region is in the southwestern portion of the San Gabriel Mountains, north of Los Angeles, California.

Stratigraphically it is composed of a section of Neogene rocks with some up-faulted older rock. The normal sequence as represented here is: Upper Modelo, unconformity; Pico, conformity; Saugus, angular unconformity; Quaternary terraces. The basement rock, composed largely of para-gneiss, schist and intrusive granite, has been faulted up from below. Its age is pre-Miocene, possibly pre-Jurassic.

The structure of the region is characterized by faults of the dip-slip vertical or steeply normal type.

Geologically the history of the region is: invasion of the sea during Miocene time, deposition of the Modelo formation, broad uplift and subsequent denudation; faulting at the opening of the Pliocene, a second incursion of the sea, deposition of the Pico formation; orogenesis north of the region here described followed by withdrawal of the sea in Upper-Pliocene time, deposition of the Saugus formation (Piedmont Deposit); active faulting and orogenesis at the close of the Pliocene; continuous erosion with short resting stages during the Quaternary.

Item Type:Thesis (Bachelor's thesis)
Subject Keywords:San Gabriel Mountains, basement rock, para-gneiss, schist, intrusive granite, Modelo Formation, Pico Formation, Saugus Formation
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 1931
Additional Information:Supplemental Files Information: Geologic Map of a part of the Southwestern Portion of the San Gabriel Mountains: Plate 1 from "Geology of a part of the southwestern portion of the San Gabriel Mountains" (Thesis). Topographic Map: Plate 2 from "Geology of a part of the southwestern portion of the San Gabriel Mountains" (Thesis) Geographic Location Bounding Box: -118.33 Degrees East; -118.4 Degrees West; 34.33 Degrees North; 34.3 Degrees South.
Record Number:CaltechTHESIS:12142009-144520602
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:12142009-144520602
Related URLs:
URLURL TypeDescription
https://doi.org/10.22002/D1.313DOISupplemental material (image) in CaltechDATA: Geologic Map of a part of the Southwestern Portion of the San Gabriel Mountains: Plate 1
https://doi.org/10.22002/D1.314DOISupplemental material (image) in CaltechDATA: Topographic Map: Plate 2
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5442
Collection:CaltechTHESIS
Deposited By: Tony Diaz
Deposited On:24 Dec 2009 19:18
Last Modified:13 Dec 2017 16:15

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