The goal of the Northern Rocky Mountains Transect (NRMT) project is to produce updated geologic maps of an important and understudied region of Idaho and western Montana that covers a wide array of distinct geologic terrains.
Science Issue and Relevance
Many geologic maps created throughout the Northern Rocky Mountains are outdated, incomplete, and do not properly adjoin neighboring maps. Objectives of the Northern Rocky Mountains Transect (NRMT) include: 1) converting available geologic maps into the digital standard Geologic Map Schema (GeMS) format, 2) updating these maps with any data already available, 3) conducting field studies to confirm or update prior mapping with new data, and 4) produce new maps where there currently are none. Intended products of the NRMT include seamless, up-to-date, and accurate digital maps and 3D framework models.
The NRMT is a supporting project under the U.S. GeoFramework Initiative and the National Geologic Synthesis. These programs were created to meet the 2020-2030 strategic plan for the USGS National Cooperative Geologic Mapping Program of producing a seamless, variable scale, 2D and 3D geologic framework of the U.S. Accurate geologic maps and 3D framework models are necessary to help improve economic vitality and mitigate natural hazards.
The USGS Mineral Resources Program has committed considerable resources in a multi-decade effort to produce original geological, geochemical, geophysical, and mineral deposit studies of 1°x2° quadrangles in the conterminous U.S. The twelve quadrangles chosen for the NRMT are significant because they cover a large area of mining and ore deposit exploration activities and have significant resource potential. Several of these quadrangles include areas identified for detailed studies of critical minerals by State geological agencies, with funding from the USGS Earth Mapping Resources Initiative, as well as USGS Mineral Resources Program. By completing and updating the geologic maps and framework models chosen for this project, the NRMT can assist the exploration and resource assessment process in this area.
Methods to Address Issue
The NRMT will provide a regional north-south transect of 1:250,000-scale maps in the northern Rocky Mountains of Idaho and southwestern Montana that cover twelve 1°x2° quadrangles. Some overlapping 1:100,000-scale maps published by State agencies will be integrated into the 1:250,000 quadrangles. As well, newer unpublished USGS mapping will be added and two previously unavailable 1°x2° quadrangles will be completed to fill a central gap.
The process involves the steps
- Capture and compare data for geologic units across maps
- Convert maps to the digital formats and the Geologic Map Schema (GeMS) standard
- Update geology from more recent sources as available
- Gather new data where absent or in need of correction or updates
- Integrate geology among the quadrangles
- Produce interpretive cross sections for each quadrangle
National Geologic Synthesis
The U.S. GeoFramework Initiative
The National Geologic Map Database (NGMDB)
- Overview
The goal of the Northern Rocky Mountains Transect (NRMT) project is to produce updated geologic maps of an important and understudied region of Idaho and western Montana that covers a wide array of distinct geologic terrains.
Sources/Usage: Public Domain.Rockslide near Riggins, ID, that brought down parts of a rock unit that inspired a whole new mapping effort and a new interpretation for the area of a 30'x60' quad that involves a 50 million year extension in duration of activity along Salmon River suture. Science Issue and Relevance
Many geologic maps created throughout the Northern Rocky Mountains are outdated, incomplete, and do not properly adjoin neighboring maps. Objectives of the Northern Rocky Mountains Transect (NRMT) include: 1) converting available geologic maps into the digital standard Geologic Map Schema (GeMS) format, 2) updating these maps with any data already available, 3) conducting field studies to confirm or update prior mapping with new data, and 4) produce new maps where there currently are none. Intended products of the NRMT include seamless, up-to-date, and accurate digital maps and 3D framework models.
The NRMT is a supporting project under the U.S. GeoFramework Initiative and the National Geologic Synthesis. These programs were created to meet the 2020-2030 strategic plan for the USGS National Cooperative Geologic Mapping Program of producing a seamless, variable scale, 2D and 3D geologic framework of the U.S. Accurate geologic maps and 3D framework models are necessary to help improve economic vitality and mitigate natural hazards.
The USGS Mineral Resources Program has committed considerable resources in a multi-decade effort to produce original geological, geochemical, geophysical, and mineral deposit studies of 1°x2° quadrangles in the conterminous U.S. The twelve quadrangles chosen for the NRMT are significant because they cover a large area of mining and ore deposit exploration activities and have significant resource potential. Several of these quadrangles include areas identified for detailed studies of critical minerals by State geological agencies, with funding from the USGS Earth Mapping Resources Initiative, as well as USGS Mineral Resources Program. By completing and updating the geologic maps and framework models chosen for this project, the NRMT can assist the exploration and resource assessment process in this area.
Sources/Usage: Public Domain.The Northern Rocky Mountains transect consists of twelve 1°x2° quadrangles in Idaho and western Montana. Methods to Address Issue
The NRMT will provide a regional north-south transect of 1:250,000-scale maps in the northern Rocky Mountains of Idaho and southwestern Montana that cover twelve 1°x2° quadrangles. Some overlapping 1:100,000-scale maps published by State agencies will be integrated into the 1:250,000 quadrangles. As well, newer unpublished USGS mapping will be added and two previously unavailable 1°x2° quadrangles will be completed to fill a central gap.
The process involves the steps
- Capture and compare data for geologic units across maps
- Convert maps to the digital formats and the Geologic Map Schema (GeMS) standard
- Update geology from more recent sources as available
- Gather new data where absent or in need of correction or updates
- Integrate geology among the quadrangles
- Produce interpretive cross sections for each quadrangle
Sources/Usage: Public Domain.Pioneer Mountains metamorphic core complex – gray peaks (middle) are in the lower plate that is separated by a detachment fault on both sides, overlain by Ordovician through Silurian yellow metasedimentary units (right and middle left) that make up the middle plate which is separated by another detachment fault overlain by later Paleozoic units (left).
Sources/Usage: Public Domain.Pre-historic Nez Perce trail from the Wallowa Mountains of Oregon to the Great Plains to hunt bison. Ponderosa pine shows scars from the harvesting of cambium as a food source on those trips.
Sources/Usage: Public Domain.Historic Bayhorse mining district millsite in foreground to thick dolostone cliffs of disputed age--either Lower Ordovician or Neoproterozoic, a difference in interpretations of about 100 million years ago. The Bayhorse Mining district was one of the longest-running silver and lead producers in Idaho.
Sources/Usage: Public Domain.Exposure of breccia marking trace of normal fault. Clasts of country rock include Eocene granite dike materials and thus provide an age for the fault as Eocene or younger. - Science
National Geologic Synthesis
The National Cooperative Geologic Mapping Program (NCGMP) Strategic Plan of 2020 calls for the creation of a “variable-scale, national, integrated 2D and 3D geologic-framework model that enables the seamless construction of geologic maps within user-defined regions of interest across the United States by the year 2030” (USGS Open-File Report 2021-1013*). Congress recently directed NCGMP to “bring...The U.S. GeoFramework Initiative
The U.S. GeoFramework Initiative (USGI) is constructing a multi-resolution, seamless national 2D and 3D geologic maps and framework models by leveraging previous and existing geologic mapping efforts by both the USGS and State Geological Surveys to provide new regional- to National-scale geologic syntheses and support digital databases for 21st Century geologic mappers and many end users. By...The National Geologic Map Database (NGMDB)
The National Geologic Map Database (NGMDB) is a distributed archive of geoscience information for the Nation. It was mandated by the Geologic Mapping Act of 1992 and is cooperatively built and maintained by the USGS and State Geological Surveys. We welcome you to explore the archive, view the maps, and help us to improve this resource. - Data
- Publications