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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

April 5, 2023

This preliminary geologic map presents mapping of the Leuhman Ridge area of Edwards Air Force Base, California, conducted between April 2020 and June 2021. The report focuses on surficial materials and bedrock to evaluate potential faults and other geologic features that may influence groundwater movement. The preliminary work confirms that the Spring Fault, previously mapped by Dibblee (1960, 1967), is a Quaternary-active fault but does not find convincing evidence to support the existence of the Leuhman Fault (Dibblee, 1960; 1967) within the map area. Several more possible and probable faults are identified by a combination of geomorphic lineaments and brecciated rock. Pleistocene and Holocene eolian deposits are widespread, manifesting as sand sheets, dunes, and admixtures into alluvial fans. Also, an incised pediment forms much of the upland south of Leuhman Ridge. In general, field observations indicate that Quaternary alluvial and eolian deposits are thin; this suggests that secondary bedrock porosity and permeability, defined by degree of weathering and fracture density that includes fault-related fracturing, are more important factors in the location and flow patterns of groundwater.

Publication Year 2023
Title 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
DOI 10.3133/ofr20231014
Authors Andrew J. Cyr, David M. Miller
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2023-1014
Index ID ofr20231014
Record Source USGS Publications Warehouse
USGS Organization Geology, Minerals, Energy, and Geophysics Science Center
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