UPDATING THE GEOLOGIC AND STRUCTURE MAPS OF THE WALLACE AND KALISPELL 1 X 2 DEGREES QUADRANGLES, MONTANA AND IDAHO, USA, AND ALBERTA AND BRITISH COLUMBIA, CANADA

Abstract

The United States Geological Survey (USGS) is updating the geologic and structure maps of the Wallace and Kalispell 1 x 2 degrees quadrangles, which together cover approximately 33,000 square kilometers in Montana and Idaho, USA, and Alberta and British Columbia, Canada. The Wallace map was originally published in 1986 by Jack Harrison and others as USGS Miscellaneous Investigations Series Map I-1509-A, and the Kalispell map was originally published in 1992 by Jack Harrison and others as USGS Miscellaneous Investigations Series Map I-2267. Both maps were then digitized by staff at the USGS' Earth Resources Observation Systems Data Center prior to 1994; digitization that would allow input into a geographic information system (GIS) was completed by USGS staff and contractors at the Spokane Field Office in 2000. Our updates will occur in two steps. First, we have updated the digital data in the attribute tables and geospatial features (points, lines, and polygons) in a format that complies with the Geologic Map Schema (GeMS). The GeMS is a new (2020) USGS standardized database design for the digital publication of geologic maps that is intended to bridge the gap between traditional geologic mapping and GIS communities at an operational level. Our data releases present the geologic maps as shown on the original map plates and captured in geospatial data for the published map. Minor errors, such as mistakes in line decoration or differences between the digital data and the map image, are corrected in these versions, but both maps faithfully represent the original publications. The modernized GIS data for both maps will be published before the Geological Society of America’s 2021 annual meeting. The second updates will involve new geologic mapping, as well as synthesizing other published geologic maps and reports, to provide significant updates on stratigraphic and structural data, age data for intrusive rocks, and interpretations of geologic development. Updating these geologic maps is foundational and a high priority for the USGS to facilitate on-going research and activities such as geologic mapping, petrologic studies, hazard assessments, mineral prospectivity mapping, energy assessments, and geoenvironmental evaluations.