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A Magnetic Survey of Sand Canyon for Placer Deposits, San Gabriel Mountains, California


Dehlinger, Peter (1943) A Magnetic Survey of Sand Canyon for Placer Deposits, San Gabriel Mountains, California. Master's thesis, California Institute of Technology. doi:10.7907/CPV2-4136.


A magnetic survey was made in Sand Canyon, which is in the northwestern part of the San Gabriel Mountains, the object being to locate possible placer deposits. The bedrock in this area is an iron rich igneous rock which has been intruded by numerous dikes. The stream gravels consist of large boulders interspersed with highly magnetic sands. Over 200 stations were involved in the survey in which vertical magnetic intensity was measured using a Schmidt-type vertical magnetometer. Magnetic anomalies found were so large that all instrument corrections were ignored. Results of the survey show that the magnetic intensity readings are due to both the basement and the gravels, though the gravels have a greater effect. The location of the largest anomalies, thus the most probable placers, is at the eastern end of the area. Downstream from this site the intensity decreases rather uniformly; upstream it decreases very sharply where the canyon narrows suddenly. Geologically, this is the expected picture. It is thought that a fault has been located, which strikes up the canyon, but this has not been confirmed by surface evidence. Data and profiles of the traverses, and a detailed map of the magnetic intensities of the region are included in this paper.

Item Type:Thesis (Master's thesis)
Subject Keywords:(Geology) ; Sand Canyon, San Gabriel Mountains, placer deposits
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Potapenko, Gennady W.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 June 1943
Additional Information:Supplemental Files Information: Map of magnetic survey, Sand Canyon, San Gabriel Mountains, California: Supplement 1 from "A magnetic survey of Sand Canyon for placer deposits, San Gabriel Mountains, California" (Thesis). Date(s) Collected: 1943.
Record Number:CaltechTHESIS:03052010-085246594
Persistent URL:
Related URLs:
URLURL TypeDescription 1 in CaltechDATA: Map of magnetic survey, Sand Canyon, San Gabriel Mountains, California
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5576
Deposited By: Tony Diaz
Deposited On:12 Apr 2010 18:47
Last Modified:10 Nov 2023 17:20

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