Bedrock geologic map database for the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado

This data release presents geologic map data for the bedrock geology of the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado. Geologic mapping incorporates new interpretive contributions and compilation from published geologic map data sources primarily ranging from 1:24,000 to 1:50,000 scale. Much of the geology incorporated from published geologic maps is adjusted based on digital elevation model and natural-color image data sources to improve spatial resolution of the data. Spatial adjustments and new interpretations also eliminate mismatches at source map boundaries. This data set represents only the bedrock geology; deposits of unconsolidated, surficial materials that are typically, but not exclusively, Quaternary in age, are not included in this database. Bedrock in the context of this database includes all metamorphic, sedimentary, and igneous rocks regardless of age. Bedrock geology is continuous to the extent that map units and structures can be appropriately constrained, including throughout areas overlain by surficial deposits. Line features that are projected through areas overlain by surficial deposits are generally attributed with lower identity and existence confidence, larger locational confidence values, and a compilation method in the MethodID field indicating features were projected beneath cover (see Turner and others [2022] for a description of MethodID field). Map units represented in this database range from Paleoproterozic and Mesoproterozic metamorphic and intrusive rocks to Pliocene and Quaternary sedimentary and volcanic rocks. Map units and structures in this data set reflect multiple events that are significant at regional and continental scales including multiple Proterozoic accreted terranes, magmatic episodes, supracrustal depositional environments, and continental margin environments, Ancestral Rocky Mountains, Laramide orogeny, Southern Rocky Mountains volcanism, and Rio Grande rift in the Phanerozoic. Map units are organized within geologic provinces as described by the Seamless Integrated Geologic Mapping (SIGMa) (Turner and others, 2022) extension to the Geologic Map Schema (GeMS) (USGS, 2020). Geologic provinces are used to organize map units based on time-dependent, geologic events rather than geographic or rock type groupings that are typical of traditional geologic maps. The detail of geologic mapping is approximately 1:100,000-scale depending on the scale of published geologic maps and new mapping based on field observations or interpretation from basemap data. The database follows the schema and structure of SIGMa (Turner and others, 2022) that is an extension to GeMS (USGS, 2020). Turner, K.J., Workman, J.B., Colgan, J.P., Gilmer, A.K., Berry, M.E., Johnstone, S.A., Warrell, K.F., Dechesne, M., VanSistine, D.P., Thompson, R.A., Hudson, A.M., Zellman, K.L., Sweetkind, D., and Ruleman, C.A., 2022, The Seamless Integrated Geologic Mapping (SIGMa) extension to the Geologic Map Schema (GeMS): U.S. Geological Survey Scientific Investigations Report 2022–5115, 33 p., https://doi.org/ 10.3133/ sir20225115. U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema)-A standard format for the digital publication of geologic maps: U.S. Geological Survey Techniques and Methods, book 11, chap. B10, 74 p., https://doi.org/10.3133/tm11B10.