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A geologic section from the Sierra Nevada to Death Valley, California

Citation

Hopper, Richard H. (1939) A geologic section from the Sierra Nevada to Death Valley, California. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-02012006-130620

Abstract

This paper describes the geology of an area six miles wide and 67 miles long, extending from the crest of the Sierra Nevada to the floor of Death Valley approximately along the 36°16' parallel of latitude. Structural geology is emphasized. Correlations are suggested between events in the geologic histories of this area and of other areas in southeastern California.

The area mapped is in one of the most rugged parts of the Great Basin, and has a relief of more than 10,000 feet. It extends across the three westernmost ranges of the Great Basin in this latitude, the Coso, Argus, and Panamint Ranges. The topographic features of these ranges strongly suggest that each of them owes most of its present relief to uplift by faulting. In the western half of the area the displacements of an extensive sheet of late Pliocene or early Pleistocene basalt support the topographic evidence of faulting. On the summit portions of the ranges are areas of low relief, believed to be remnants of a single old-age erosion surface which extended across the area before the beginning of the range-forming fault movements. The period of undisturbed erosion which produced this surface ended shortly before the deposition of the fossiliferous late Pliocene or early Pleistocene Coso formation; therefore this surface is correlated with the Ricardo erosion surface of the Mohave Desert region, which bevels tilted early Pliocene strata and which is also dislocated by range-forming faults.

The ranges are composed dominantly of pre-Tertiary rocks. Pre-Cambrian metasediments exposed in the Panamint Range attain a thickness of 15,000 feet; they are chiefly mica schists and dolomites. The Paleozoic rocks are more than 30,000 feet thick, and the fossils collected indicate the probable presence of all the Paleozoic systems. Limestones, dolomites, shales, and quartzites are the principal rock types. Cambrian and Carboniferous strata make up about three-fourths of the total Paleozoic section. During the late Jurassic Nevadian orogeny the pre-Mesozoic rocks were folded, faulted, and intruded by platonic bodies ranging in composition from granite to gabbro. The post-Mesozoic rocks are almost entirely of late Cenozoic age, and include a wide variety of volcanic and sedimentary types.

Movements of large magnitude took place on the fault zone on the east edge of Panamint Valley in late Tertiary time, and activity on this zone has continued into the Recent epoch. Most of the faulting to which the region owes its present relief, however, occurred in the early or middle part of the Pleistocene epoch, probably after the first (McGee) glacial stage in the Sierra Nevada. All the range-forming faults whose attitudes could be determined were found to be normal faults.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geological and Planetary Sciences
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Buwalda, John P.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1939
Record Number:CaltechETD:etd-02012006-130620
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-02012006-130620
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:431
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:06 Feb 2006
Last Modified:26 Dec 2012 02:29

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