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“Budding” Positive Flower Structure along The Northern Death Valley Fault Zone, Death Valley, California

Knott, Jeffrey R.*1
(1) Geological Sciences, CSU Fullerton, Fullerton, CA.

Death Valley is a lazy-Z strike-slip basin developed by slip on the right-lateral Northern Death Valley/Furnace Creek and Southern Death Valley fault zones with the intervening normal-slip Black Mountains fault zone. The Northern Death Valley fault zone (NDVFZ) is a cross-valley fault that is now the locus of Quaternary deformation in lieu of the Furnace Creek fault zone. For most of its trace the NDVFZ is a low-relief, linear fault, with the exception of the 250-m-high Kit Fox Hills (KFH). The KFH consist of Miocene (?) to Quaternary uplifted and tilted lacustrine and alluvial-fan deposits mapped at 1:62500 scale. Mapping at 1:12000 and geochronology including 17 tephra layers distributed throughout the KFH indicate that KFH deposits range in age from ~3.5 Ma to <0.76 Ma. Structurally, the KFH are consistent with an emerging positive flower structure that is elongating from south to north. In the south where the greatest relief is found, deposits that include the 3.335 Ma Zabriskie Wash tuff are deformed in an overturned anticline with trend oblique to the NDVFZ. Beds in the central KFH are east-tilted and interrupted by faults with apparent normal, down-to-the-north offset and strikes about 30-45° from the strike of the NDVFZ. In the north, 0.76 Ma deposits that include the 0.76 Ma Bishop Ash bed are folded into a broad syncline that trends parallel to the NDVFZ. In addition, the northern KFH are characterized by down-to-the-northwest normal faults with arcuate strikes. Proximal to the NDVFZ, the strikes of the normal faults are at a 45° angle to the NDVFZ. Distally, these same normal faults strike parallel to the NDVFZ. I interpret the older deposits, greater structural complexity and greater relief in the relative to the north as south to north growth of the KFH. The secondary faults and folds are consistent with modeled and observed positive flower structures in a simple shear environment.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California