Structural analysis of the central Ibex Hills, Death Valley, California

Oscar Esparza, University of Texas at El Paso


The Ibex Hills, in southern Death Valley, California, are composed mainly of Late Proterozoic sedimentary rocks overlying middle Proterozoic basement that are complexly deformed by Mesozoic contractional structures overprinted by Neogene extensional/transtensional structures. Detail mapping of the Ibex Hills reveals evidence of several deformational events. Brittle deformation of both extensional and strike-slip origin are recognized throughout the mapped area, but the main structure identified is a low angle fault at the base of the Noonday Dolomite, Sentinel Peak member, herein called the Noonday Fault. This low angle fault is dipping toward the east-northeast and has a curved geometry that resembles a previously mapped fault ∼4 km west of the study area. The Noonday Fault accounts for missing section in the upper Crystal Springs Formation, Becks Springs Formation, and the Kingston Peak Formation. The Noonday Fault contact places the Sentinel Peak member on the middle Crystal Springs Formation. This fault is the most continuous feature in the area until terminating into the eastern bounding fault of the area. This eastern bounding fault is observed as a steeper normal fault dipping to the east with a dextral slip component. These Neogene structures overprint a complex Mesozoic deformation that includes at least two generations of folds. Overprinting has led to a general noncylindrical geometry for these folds, but the associated cleavages are also refolded complexly suggesting at least three phases of fold systems, sheath fold development or both.

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Recommended Citation

Esparza, Oscar, "Structural analysis of the central Ibex Hills, Death Valley, California" (2012). ETD Collection for University of Texas, El Paso. AAI1533222.