Surficial geologic map database of the southeast 3/4 of the Las Vegas 1-degree by 2-degree quadrangle, southern Nevada: Contributions to the National Geologic Map

This data release presents geologic map data for the surficial geology of the Overton, Lake Mead, and Las Vegas 30-minute by 60-minute quadrangles, Arizona, Utah, and Nevada. This 1:100,000 scale geologic mapping incorporates new interpretive contributions and compilation from 1:24,000 to 1:250,000 scale published geologic map data sources. Geology incorporated from previous mapping has sometimes been adjusted with Light Detection and Ranging (LiDAR) 1-meter digital elevation models, satellite imagery, and field observations in key localities to improve spatial resolution of the data and eliminate mismatches at source map boundaries. This data set represents only the surficial geology, defined as generally unconsolidated sedimentary deposits that are Quaternary or partly Quaternary in age. Bedrock, volcanic deposits, and faults without documented Quaternary offset are not included in this database, but are instead published in a separate companion bedrock database of the same footprint. The surficial data set occurs entirely within the Basin and Range physiographic province. This physiographic province is split further into subprovinces based on general deposit type; alluvium, colluvium, alluvium/colluvium, eolian, mass wasting, lacustrine, and groundwater discharge; which host the specific map units that are binned by age (e.g., Holocene, Pleistocene, Quaternary undivided) as relevant to available information, chronology, and map scale. Map unit polygons also include attributes such as constituent material, genetic type, compilation method, and links to the source map(s) from which data was compiled. Gaps in map compilation are related to a lack of published geologic mapping at the time of compilation, and not necessarily a lack of surficial deposits. The database follows the schema and structure of the Seamless Integrated Geologic Mapping (SIGMa; Turner and others, 2022) extension to the Geologic Map Schema (GeMS; USGS, 2020). The geologic data in this data release will be published through a USGS publication series, for example Open-file report, as a static, cartographic representation of the surficial geology and will include a more detailed description of mapping methods. The cartographic map published through the USGS publication series will reflect a single visualization of the data and will be associated with a specific version of this data release, whereas this data release may be versioned as the state of geologic knowledge throughout the region evolves. This data release and subsequent versions will be the most current and authoritative source of the geologic information.