The Flatirons, Chautauqua Park, Boulder, CO (December, 2026 CGS Geology Calendar). Photo credit: Orna Buch-Leviatan (CGS) 12/03/2025 2026 Colorado Geology Calendar Brought back for its fourth year running, our popular annual wall calendar showcases a varied and beautiful photo tour around the state. We’re excited to share this next collection of photographs from our talented CGS staff members (both current and former). Designed to keep you visually “in-the-know” on colorful Colorado… Read More
North and South Table Mountain, Golden, CO. Photo credit: Emily Perman (CGS) 11/20/2025 Colorado Geological Survey Research Notes Here at the Colorado Geological Survey, our publications library is constantly evolving and growing. Our publications archive is always being updated, and new items are published to our website on a monthly basis. All this work is in pursuit of our mission statement: To reduce the impact of geologic hazards… Read More
Cover for RN-04 Glacial outburst floods on the Lake Fork of the Gunnison River, Colorado 11/19/2025 RN-04 Glacial outburst floods on the Lake Fork of the Gunnison River, Colorado *PUBLICATION DISCLAIMER* Research Notes (RN) publications are intended to provide members of the geoscience community with an avenue for publishing independent research and for supporting scientific exchange and the preservation of observations and interpretations. These publications have not been subject to the typical Colorado Geological Survey review process, but… Read More
Cover for RN-03 Glacial outburst floods on the Uncompahgre River, Colorado 11/19/2025 RN-03 Glacial outburst floods on the Uncompahgre River, Colorado *PUBLICATION DISCLAIMER* Research Notes (RN) publications are intended to provide members of the geoscience community with an avenue for publishing independent research and for supporting scientific exchange and the preservation of observations and interpretations. These publications have not been subject to the typical Colorado Geological Survey review process, but… Read More
Cover for RN-02 Glacial outburst floods on the Animas River, Colorado and New Mexico 11/19/2025 RN-02 Glacial outburst floods on the Animas River, Colorado and New Mexico *PUBLICATION DISCLAIMER* Research Notes (RN) publications are intended to provide members of the geoscience community with an avenue for publishing independent research and for supporting scientific exchange and the preservation of observations and interpretations. These publications have not been subject to the typical Colorado Geological Survey review process, but… Read More
Cover for RN-01 The Vallecito flood— a catastrophic flood on Los Pinos River, southern San Juan Mountains, Colorado and New Mexico 11/19/2025 RN-01 The Vallecito flood— a catastrophic flood on Los Pinos River, southern San Juan Mountains, Colorado and New Mexico *PUBLICATION DISCLAIMER* Research Notes (RN) publications are intended to provide members of the geoscience community with an avenue for publishing independent research and for supporting scientific exchange and the preservation of observations and interpretations. These publications have not been subject to the typical Colorado Geological Survey review process, but… Read More
09/17/2025 Technology Accessibility Statement Colorado Geological Survey Technology Accessibility Statement At the Colorado Geological Survey, we are continuously working towards meeting the recommendations outlined in the Web Content Accessibility Guidelines version 2.1, levels A and AA (WCAG 2.1 AA). These guidelines not only help make web content accessible to users with… Read More
ON-006-18D Alluvial Fan Mapping of Pitkin County, Colorado (Data) - v20250716 07/17/2025 ON-006-18D Alluvial Fan Mapping of Pitkin County, Colorado (Data) – v20250716 The CGS develops and provides a variety of geologic hazard maps for various state and local governments with land use and hazard mitigation planning in mind. Pitkin County officials expressed concern about their preparedness for post-wildfire natural hazards and asked the CGS to more completely define… Read More
OF-23-03 Geologic Map of the Loveland Quadrangle 07/14/2025 OF-23-03 Geologic Map of the Loveland Quadrangle, Larimer County, Colorado The purpose of this publication is to describe the geology, mineral and groundwater resources, and geologic hazards of the Loveland 7.5-minute quadrangle. It is a continuation of field mapping work on the northern Front Range of Colorado where the CGS has mapped multiple quadrangles, this one covering the area around… Read More
MS-55 Cenozoic Stratigraphy of Colorado 05/21/2025 MS-55 Cenozoic Stratigraphy of Colorado As a successor to previous Colorado stratigraphy charts (MS-53 Colorado Stratigraphic Chart and MS-54 Cretaceous Stratigraphy of Colorado), this publication resulted from a collaboration between the CGS, USGS, and the Denver Museum of Nature and Science (DMNS). The chart… Read More
OF-24-13 Baseline Radiological Study Year 3: San Luis Valley 05/21/2025 OF-24-13 Baseline Radiological Study Year 3: San Luis Valley The Colorado Geological Survey (CGS), a department of the Colorado School of Mines, has been funded through a grant from the Colorado Department of Public Health & Environment (CDPHE) to conduct a 5‐year study of baseline naturally occurring radionuclides and metals in groundwater obtained from privately owned residential water wells… Read More
OF-24-08 Baseline Radiological Study Year 3: Uravan Belt 05/20/2025 OF-24-08 Baseline Radiological Study Year 3: Uravan Belt The Colorado Geological Survey (CGS), a department of the Colorado School of Mines, has been funded through a grant from the Colorado Department of Public Health & Environment (CDPHE) to conduct a 5-year study of baseline naturally occurring radionuclides and metals in groundwater obtained from privately owned residential water wells… Read More