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Geology and mechanics of the Blackhawk landslide, Lucerne Valley, California

Citation

Shreve, Ronald Lee (1959) Geology and mechanics of the Blackhawk landslide, Lucerne Valley, California. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-02212006-085518

Abstract

Blackhawk Mountain, a resistant mass of marble thrust northward over uncemented sandstone and weathered gneiss, rises above southeastern Lucerne Valley at the eastern end of the rugged 4000-foot escarpment that separates the San Bernardino Mountains on the south from the Mojave Desert on the north. Spread out on the alluvial apron at the foot of the mountain is the Blackhawk rockslide, a lobe of nearly monolithologic marble breccia 30 to 100 feet thick, 2 miles wide, and nearly 5 miles long. At least two earlier similar but smaller rockslides have occurred in the area.

The rocks of the area comprise late Tertiary and Quaternary fanglomerates and breccias derived mainly from the gneiss, quartzite, Carboniferous marble, and Cretaceous quartz-monzonite of the San Bernardino Mountains. Uplift of Blackhawk Mountain occurred in two stages after deposition of the older fanglomerates and breccias: the first by over-thrusting from the south, and the second by monoclinal folding along a northwest-trending axis.

Geological evidence in the area shows that the Blackhawk rockslide traversed the gently inclined alluvial slope as a nearly nondeforming sheet of breccia moving more than 50 miles per hour. The hypothesis that compressed air, rather than water or mud, constituted the lubricating layer on which the breccia sheet slid qualitatively explains all of the principal physical features of the slide lobe. Theoretical analysis of the flow in the lubricating air layer indicates the quantitative feasibility of the air-lubrication hypothesis for the Blackhawk slide.

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):
  • Sharp, Robert P.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1959
Record Number:CaltechETD:etd-02212006-085518
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-02212006-085518
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:691
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:01 Mar 2006
Last Modified:26 Dec 2012 02:31

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