HR: 1340h
AN: T33C-1395    [Abstracts]
TI: Gravity Study of the Fish Lake Valley Area, Nevada.
AU: * Black, R A
EM: black@ku.edu
AF: Dept. of Geology, University of Kansas, 120 Lindley Hall, 1475 Jayhawk Blvd., Lawrence, KS 66045 United States
AU: Stockli, D F
EM: stockli@ku.edu
AF: Dept. of Geology, University of Kansas, 120 Lindley Hall, 1475 Jayhawk Blvd., Lawrence, KS 66045 United States
AU: Deymonaz, J
AF: Fish Lake Green Power Company, MM8, Hwy. 264 P.O. Box 258, Dyer, NV 89010 United States
AU: Maas, J
AF: Consultant, 5256 Magnolia, Riverside, CA 92506 United States
AB: The regional releasing bend within the central Walker Lane Belt (WLB), know as the Mina Deflection, is characterized by rhomboidal pull-apart basins and associated NE-trending normal faults that transfer the strike-slip displacement between the right-lateral transcurrent northern and southern portions of the WLB. A prominent example can be found at the northern end of Fish Lake Valley (FLV), where right-lateral displacement along the Fish Lake Valley-Furnace Creek fault zone feeds northward into a large right-stepping pull-apart structure, bounded by the Emigrant Peak normal fault system. Existing regional gravity archives, available from federal agencies, are adequate for characterizing general features of FLV and other nearby basins. Regional coverage is very sparse within surrounding ranges, however. Over 900 new gravity data points have been acquired in the FLV and surrounding ranges in support of ongoing geothermal studies of the area. The new data coverage is detailed enough to constrain the subsurface geometry of the range bounding faults and the projection of outcropping lithologies in the ranges into the basins. In conjunction with an ongoing program at KU of detailed geological field mapping to refine the lithologies and tectonic history of the ranges, a detailed gravity modeling project is also being undertaken to extend the new interpretations into the subsurface and to allow quantitative estimates of basement depth, fault offsets, and sediment volumes within the FLV. Prominent features seen in preliminary results include a steep range-bounding fault at the north end of the FLV with an apparent depth to basement of over one km immediately to the south of the fault, and large gravity highs due to metasedimentary rocks within the Paleozoic section.
DE: 8015 Local crustal structure
DE: 8107 Continental neotectonics
DE: 8122 Dynamics, gravity and tectonics
DE: 0920 Gravity methods
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting