Preliminary surficial geologic map of Leuhman Ridge and the surrounding area, Edwards Air Force Base and Air Force Research Laboratory, Kern and San Bernardino Counties, California

First posted April 5, 2023 For additional information, contact: Contact Information,Geology, Minerals, Energy, & Geophysics Science CenterMenlo Park, CaliforniaU.S. Geological SurveyBuilding 19, 350 N. Akron Rd.P.O. Box 158Moffett Field, CA 94035 This preliminary geologic map presents mapping of the Leuhman Ridge area Edwards Air Force Base, California, conducted between 2020 and June 2021. The report focuses on surficial materials bedrock to evaluate potential faults other features that may influence groundwater movement. work confirms Spring Fault, previously mapped by Dibblee (1960, 1967), is a Quaternary-active fault but does not find convincing evidence support existence Fault (Dibblee, 1960; 1967) within area. Several more possible probable are identified combination geomorphic lineaments brecciated rock. Pleistocene Holocene eolian deposits widespread, manifesting as sand sheets, dunes, admixtures into alluvial fans. Also, an incised pediment forms much upland south Ridge. In general, field observations indicate Quaternary thin; this suggests secondary porosity permeability, defined degree weathering fracture density includes fault-related fracturing, important factors in location flow patterns groundwater.