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The end result of the current trenching on the Cheraw fault, near Arlington, Colorado, April 2019. Photo credit: Matt Morgan for the CGS.

Trenching the Cheraw Fault in Southeastern Colorado

One of the missions of the CGS is to better understand the various geological risks that face the residents of…

A uranium-rich zone in a sandstone of the Morrison Formation, Carnation Mine, San Miguel County, Colorado, January 2007. Photo credit: Colorado Geological Survey.

Colorado’s Uranium Deposits

[Ed: this document, written in 2011 by Jim Burnell, Ph.D., P.G. (former Senior Minerals Geologist, Colorado Geological Survey), provides an…

Slice of a pallasite meteorite, illustrating large olivine (peridot) crystals in a matrix of nickel-iron minerals. This specimen, known as the Brenham meteorite (DMNH EGT.23.0), is from Haviland, Kansas, and is ~25 cm wide. Photo credit: R. Wicker for the Denver Museum of Nature and Science.

DMNS Meteorite Collection

The Meteorite Collection of the Denver Museum of Nature & Science publication

Mount Garfield from Interstate-70, Mesa County, Colorado, March 2016. Photo credit: Larry Scott for the CGS.

Welcome to the final CGS/RockTalk web iteration

If you want to find out what's happening with the new CGS site, read here! Apologies for the incompleteness, it will improve on a daily basis, we promise!

Erosional regime, Red Rock Canyon, Dinosaur National Moument, Colorado, May ©2012 hopkins/neoscenes

Quote: Robert Frost, geohazards expert

Not only sands and gravels Were once more on their travels, But gulping muddy gallons…

Colorado Geological Survey Logo

Site development

We’re excited to finally get down to the next round of our web development with Fireant…

Uranium roll front hosted in Dakota Sandstone, Turkey Creek Road road-cut, Dakota Hogback, near Denver, Colorado. Photo credit: James St. John.

Geology of Uranium Deposits in Colorado

Uranium is a widespread and ubiquitous element. It has a crustal abundance of 2.8 parts per million, slightly more than…

Piping cave/soil arch in Qamf deposit, Loutzenhizer Arroyo, Delta County, Colorado, April 2007. Photo credit: David Noe for the CGS.

Collapsible Soils

By Jonathan White, Senior Engineering Geologist (emeritus staff) At the end of the 19th and beginning…

Erosional regime, Red Rock Canyon, Dinosaur National Moument, Colorado, May ©2012 hopkins/neoscenes

Quote: Creative geologic ideas?

No Geologist worth anything is permanently bound to a desk or laboratory, but the charming notion that true science can…

A Brief History of Colorado Through Time (Geology of Colorado)

One of the many fascinating videos from our geo-friends up the road at University of Colorado-Boulder:…

Diamonds in the rough, note the regular octahedral forms and trigons (of positive and negative relief) formed by natural chemical etching. Photo credit: Wikimedia.

What are diamonds?

Diamonds are formed from pure carbon, one of the most abundant elements on planet Earth. Diamonds, even from ancient times,…

Subsidence (Water Education Foundation)

Swelling or expansive soils

Colorado has many areas susceptible to the problems that swelling soils cause. This video gives some…

Water Resources Investigation WRI 2017-1a, The Upper Pierre Aquifer of the Cheyenne Basin, Northeastern Colorado, Geologic Cross Sections

A new Water Resources Investigation: Upper Pierre Aquifer

Our friends over at the Colorado Division of Water Resources (CDWR) have just released Water Resources…

MI-97 LiDAR-Based Map of the Cheraw Fault Scarp. Graphic credit: Colorado Geological Survey

AEG Annual Meeting

Members of our geoscience staff are busy this week participating in the Annual Meeting of the…

Dramatic landslide headscarp threatens this structure on Constellation Drive in Skyway, Colorado Springs, Colorado, May 2017. Photo credit: Jon Lovekin, PG for the CGS.

Landslide Hazard Info for Colorado Springs Residents and Real Estate Professionals

Dramatic landslide headscarp threatens this structure on Constellation Drive in Skyway, Colorado Springs, Colorado, May 2017. Photo credit: Jon Lovekin,…

ON-001 Colorado Earthquake and Fault Map

What to do before, during, and after an earthquake

Earthquakes strike suddenly, violently, and without warning. While Colorado is not as seismically active as some places, it does have…

OF-16-02 Geologic Map of the Watkins Quadrangle, Arapahoe and Adams Counties, Colorado

OF-16-02 Geologic Map of the Watkins Quadrangle, Arapahoe and Adams Counties, Colorado

We’ve just uploaded the next of our free STATEMAP quadrangle map products to…

West Salt Creek rock avalanche viewed from the air, May 2014. Photo credit: Jon White for the CGS.

AASG 2017 John C. Frye Memorial Award for CGS publication

The Association of American State Geologists announced that their annual John C.

OF-16-03 Colorado Rocky Mountain Front Profiles

OF-16-03 Colorado Rocky Mountain Front Profiles

Can you name the features of the endless Rocky Mountain skyline as seen from the Front…

OF-16-05 Geologic Map of the Longmont Quadrangle, Boulder and Weld Counties, Colorado

OF-16-05 Geologic Map of the Longmont Quadrangle, Boulder and Weld Counties, Colorado

We just uploaded the most recent of our STATEMAP mapping products to…

IS-79 Colorado Mineral and Energy Industry Activities 2015-2016

IS-79 Colorado Mineral and Energy Industry Activities 2015-16

The current annual Colorado Mineral and Energy Industry Activities report 2015-16 is now available. Following up…

MS-53 Colorado Stratigraphic Chart

MS-53 Colorado Stratigraphy Chart

A collaboration between the CGS and the Denver Museum of Nature & Science (DMNS) has resulted…

The gas well pad near the terminus of the West Salt Creek rock avalanche (flow direction right to left), Mesa County, Colorado, May 2014. Photo credit: The CGS.

Top-Ten paper at GSA

On May 25, 2014 the longest landslide in Colorado’s historical record occurred in west-central Colorado, six miles southeast of the small town of…

Trimble Ref-Tek 151-30 Broadband Seismometer in subsurface housing, Briggsdale, Colorado, May 2016. Photo credit: Mike Bornowski for the CGS.

CGS seismometer array

The CGS recently installed the first of five new seismic recording stations that will collect information on seismic events around…

Land subsidence, a growing problem

Deltares, an independent institute for applied research in the field of water and subsurface, hosted fifteen…

The Science of Sinkholes

This video, from the U.S. Geological Survey, explores the geological factors behind sinkholes and the related science. Narrated by Randall…

Mine Subsidence Hazards in Colorado

This video, produced by the CGS in 2011, examines the significant geo-hazards related to the long history of underground coal…

Hazardous Soils in Colorado

This educational video, produced in 2011, explores the various problems that arise from hazardous soil conditions — expansive, collapsible/compressible,  hydrocompactive,…

Free 8.5- x 11-inch map of Colorado geology (front) along with Geo-Whizology (back).

The biggest, the best, the first, and the most diverse…

We have a free 8.5- x 11-inch (pdf) geologic map of Colorado containing Geo-Whizology of Colorado…