Identification_Information: Citation: Citation_Information: Originator: David M. Miller, U.S. Geological Survey, Geologist Publication_Date: 2020 Title: Geologic map and borehole stratigraphy of Hinkley Valley and vicinity, San Bernardino County, California Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: U.S. Geological Survey Scientific Investigations Map Issue_Identification: 3458 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/sim3458 Description: Abstract: The geology of Hinkley Valley, in the central to western Mojave Desert of southeastern California, was mapped to evaluate controls on subflow from the Mojave River, which provides groundwater recharge to the valley. A natural gas pipeline was the locus of hexavalent chromium, Cr(VI), releases into, and consequent contamination of, groundwater. Understanding the movement and fate of the contaminants is a complex hydrologic and geochemical problem. This report provides new information on surface and subsurface geology to better constrain the origin and geometry of hydrologically important deposits in the Hinkley Valley area and describes youthful faults that may control sediment distribution and groundwater flow. In addition, we analyzed gravity data to (1) map horizontal gradients that we interpret to reflect long-term fault traces and (2) estimate the depth to bedrock. The subsurface geology of Hinkley Valley was investigated by examining borehole sediment cores and rock encountered at the base of the sediment section. We analyzed the core to determine depositional environments, provenance, and age of the sediment that infilled the valley. Interpretations of aerial photographs and high-resolution topography (over a limited part of the map area) were aimed at identifying subtle geomorphic features associated with faults. Purpose: Hinkley Valley, in the central to western Mojave Desert of southeastern California, was studied to provide framework elements for use in resolving movement and fate of hexavalent chromium, Cr(VI), contaminants in the groundwater. Supplemental_Information: The schema for this geodatabase is derived, in part, from the NCGMP09--draft standard format for digital publication of geologic maps, version 1.1 (NCGMP09 v1.1), available at http://ngmdb.usgs.gov/Info/standards/NCGMP09/. Feature attributes and symbology follow the recommendations outlined in the FGDC Digital Cartographic Standard for Geologic Map Symbolization, available at https://pubs.usgs.gov/tm/2006/11A02/. The database contains the following spatial data: geology (feature dataset) - contains the following feature classes used to depict the geology and provide locations where data were collected: Hink_Geo_arc - geologic contacts and faults Hink_Geo_poly - geologic map unit polygons Hinkley_bedding- orientation data for planar geologic features Hinkley_Valley_stations - locations of data collection Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: 476662.304 East_Bounding_Coordinate: 493572.000 North_Bounding_Coordinate: 3879304.494 South_Bounding_Coordinate: 3853987.117 Coordinate system: UTM zone 11N (NAD 83 datum) Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: geologic map Theme_Keyword: Hinkley Valley Theme_Keyword: Borehole Stratigraphy Theme_Keyword: groundwater contamination Theme_Keyword: youthful faults Access_Constraints: None Use_Constraints: Not for use at scales larger than 1:24,000. Any derivative products utilizing these datasets shall clearly indicate their source. If users modify the data in any way, they are obligated to describe the types of modifications they have performed. User specifically agrees not to misrepresent these datasets, nor to imply that changes they made were approved by the USGS. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact organization: U.S. Geological Survey Contact person: David M. Miller 345 Middlefield Rd, MS 973, Menlo Park, CA 94025; dmiller@usgs.gov Data_Set_Credit: David M. Miller, Victoria E. Langenheim, and Elizabeth K. Haddon U.S. Geological Survey Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Geologic features in the geodatabase were symbolized based on attributes, plotted at 1:24,000-scale and visually reviewed for accuracy by the authors. Logical_Consistency_Report: Geologic lines and geologic units are topologically related entities. The following topology rules were employed to maintain the topological integrity of the data: geologic lines 1) must not self-overlap, 2) must not self-intersect, 3) must not have pseudonodes, 4) must not intersect or touch interior, 5) must be single part, and 6) must not have dangles [excepting faults]; geologic units 1) must not overlap, 2) must not have gaps, and 3) boundary must be covered by [geologic lines]. Completeness_Report: This geodatabase is considered complete for the time period of the content. The map area is completely mapped, and all geologic features on the source maps were digitized and attributed, as was all new mapping. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Bedrock geology for this database was digitized from georeferenced source maps, and new mapping of bedrock and surficial geology was compiled at scales from 1:12,000 to 1:24,000. Lines in feature class Hink_Geo_arc with the modifier 'location accurate' are assumed (but not guaranteed) to be located within approximately +/- 10 meters of their actual position on the ground. Lines with modifiers 'approximate' are assumed to be poorly located, and may have errors that greatly exceed +/- 15 meters. Points in all point feature classes are derived from handheld GPS units and are assumed (but not guaranteed) to be located within +/- 5 meters of their actual position on the ground. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: U.S. Geological Survey Information Services Contact_Address: Address_Type: unknown Address: Box 25286 Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80225 Country: US Contact_Voice_Telephone: 1-888-ASK-USGS Contact_Electronic_Mail_Address: ask@usgs.gov Distribution_Liability: The U.S. Geological Survey (USGS) provides these geographic data "as is." The USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. The USGS further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers at the USGS, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of delivery, installation, operation, or support by USGS. Standard_Order_Process: Fees: None Metadata_Reference_Information: Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: David Miller Contact_Position: Geologist Contact_Address: Address_Type: unknown Address: P.O. Box 158 City: Moffett Field State_or_Province: CA Postal_Code: 94035 Country: US Contact_Voice_Telephone: 650-439-2823 Contact_Electronic_Mail_Address: dmiller@usgs.gov Contact_Instructions: Please contact through email Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time