Digital database for the Surficial Geologic Map of the Owlshead Mountains 30' X 60' Quadrangle, Inyo and San Bernardino Counties, California

This geodatabase contains all of the map information used to publish the Surficial Geologic Map of the Owlshead Mountains 30’ X 60’ Quadrangle,Inyo and San Bernardino Counties, California: U.S. Geological Survey Scientific Investigations Map SIM-3496. The geodatabase and associated map delineate primarily surficial geology and neotectonics structure across the entire extent of this quadrangle, which includes 32 complete 7.5’ quadrangles located in the Owlshead Mountains, southern Death Valley, and adjoining basins and highlands in the southwestern section of Inyo County and the northeastern part of San Bernardino County in eastern California. The datasets contained in this Scientific Investigation Map describe the surficial geology within the entire map area of the Owlshead Mountains (OM) 30' X 60' Quadrangle. The geodatabase and associated geologic map delineate primarily surficial geology and neotectonics structure across the entire extent of this quadrangle, which includes 32 complete 7.5' quadrangles located in the southwestern section of Inyo County and the northeastern part of San Bernardino County in eastern California. The map encompasses a sparsely populated area that includes the southeastern corner of Death Valley National Park (DVNP) and the northeastern corner of the Fort Irwin Military Reservation, with a complex intermixture of public lands, mostly with the U. S. Bureau of Land Management, interspersed with many small scattered private holdings (mostly ranch land) and the few small municipalities of Shoshone and Tecopa. The map area encompasses a complex and diverse physiographic area dominated by the prominent feature of southern Death Valley (SDV), which is a major wide, continuous, and deep topographic trough that curves south and southeastward through the center map before connecting into the broad lowland areas of Valjean and Silurian Valleys in the eastern and southeastern map corner. The SDV trough is bounded on the northeast by the mountainous crest of the southern Black Mountains which merges northeastward into a series of north- to northeast-trending ranges and intervening valleys including Tecopa, Chicago, and southern California Valleys and the southern Resting Springs and Nopah Ranges. To the west and southwest of SDV lie the southern highlands of the Panamint Range, and Owlshead, Avawatz, and northern Granite Mountains, surrounding the linear east-trending valley of Leach Lake basin on the southwest corner of the map. The map and geodatabase for the Owlshead Mountains quadrangle was generated entirely from data originated by the database authors based primarily on new systematic photointerpretation supported by field traverses in selected areas. The geodatabase catalogues the complex geology and tectonic features responsible for producing this complex terrain. The map emphasizes spatial patterns of Quaternary sedimentation, erosion, and active deformation affecting landscape evolution in the area. Key elements of the map are a complex suite of (a) over 170 aggradational single and composite surficial units classified by both geologic age and genetic process (e.g., alluvial- and debris-flow fan, wash, axial valley, eolian, playa, lacustrine, groundwater discharge, and mass-wasting deposits,) and (b) degradational units (pediment surfaces). The surficial units overlie a generalized set of pre-Quaternary map units recognized for their potential relevance to physical and genetic attributes of the Quaternary deposits. The map also identifies an array of faults and folds, including several fault-related folds, that are differentiated by geometry and (or) slip type. Map compilation efforts emphasized the systematic depiction of surficial units and structures essential to time-space interpretations of deposition and dissection, surface-drainage evolution, and neotectonic deformation across this region. The mapped distribution and age of alluvial and fluvial deposits clearly define spatial and temporal patterns of deposition, mainly concentrated in the central trough of SDV, that contrast with areas in adjoining highlands where drainage incision is persistent. These data provide input to time-space reconstructions of regional drainages such as the lower Amargosa River. Mapped traces of faults and folds define complex and widespread neotectonic deformation centered in SDV and areas to the south and west. Active deformation is characterized by: (a) three to four regional sets of commonly intersecting dextral and sinistral translational faults (including the SDV and eastern Garlock faults); (b) zones of contraction (thrust faults and associated folds, transpressive structures, and fold belts) and uplift commonly concentrated at major fault intersections, and (c) zones of downwarping and uplift that form many of the basinal troughs (e.g. SDV) and adjoining highlands.