About This Work:  Sources



Stratigraphic Chart

This living digital chart has been built directly from a chart of Colorado Stratigraphy assembled by Richard H. Pearl published by the Rocky Mountain Association of Geologists in Special Publication 2 in 1977. The chart has been reproduced in various ways for field guides and handouts. We have recast it against the International Commission on Stratigraphy’s  Chronostratigraphic Chart v. 2015/01 and slightly modified the organization and layout.  It is designed, like Colorado, to evolve with time.


Paleogeographic Maps

These maps are the work of Ron Blakey, published in:

Blakey, R. and Ranney, W., 2008, Ancient Landscapes of the Colorado Plateau; Grand Canyon Association, 156  pp., together with maps from a CD obtained from Ron featuring additional maps of the Western Interior.  For additional details please see Ron’s publications and www2.nau.edu/rcb7


Paleogeologic Maps

Bob compiled these from the literature. They form a part of a research project at the Denver Museum of Nature & Science to examine Colorado’s evolving river systems.


Ancient Paintings

These come from the book:  Ancient Denvers: Scenes from the past 300 million years of the Colorado Front Range by Kirk Johnson and Bob Raynolds published by the Denver Museum of Nature & Science with art work by Jan Vriesen, Donna Braginetz, and Gary Staab.  Ten images, painted by Jan Vriesen, from the Colorado Convention Center have been added courtesy of the artist, the Denver Museum of Nature & Science, and the City of Denver.


Fossil Photos (Under Construction)

We are adding photos of representative Colorado fossils, using images from the Denver Museum of Nature & Science and the University of Colorado.


Strata Photos (Under Construction)

We are collecting a series of beautiful photos of rocks in Colorado. We have used photos form Jeremy McCreary’s web site at www.cliffshade.com and other resources as indicated.


Resources (Coal, Oil, Gas)

This page illustrates resources extracted in Colorado. The data have been derived from the Colorado Oil and Gas Commission, the Colorado Geological Survey and the Energy Information Administration by Kathy Robinson. The size of the circles are proportional to the resource volume extracted.


Coal Production:


• 1864-2002: Colorado Geologic Survey, Historic Coal Mines of Colorado, 2002, CD

• 2003-2013: EIA, Historical Detailed Coal Production Data, http://www.eia.gov/coal/data.cfm#production



• Reported coal units are short tons

• EIA and CGS data sets were joined using mine name

• Basins were assigned based on reported county, township, range data and relating these to position on Basin map posted on Colorado Stratigraphy website

• Formation details reported were aggregated into 10 overall formations


Oil and Gas Production:


• Historical-1996: Colorado Geological Survey, IS-50, Oil and Gas Fields of Colorado: Statistical Summary Through 1996, Allison Lawson and H. Thomas Hemborg, 1999

• 1997-1998: Colorado Oil and Gas Conservation Commission, custom data by request

• 1999-2014: Colorado Oil and Gas Conservation Commission, Production Summaries by Year, http://cogcc.state.co.us/data2.html#/downloads

• Historic field locations: http://www.eia.gov/pub/oil_gas/natural_gas/data_publications/field_code_master_list/historical/2000/pdf/fcml_all.pdf



• Reported oil units are Bbls (barrels)

• Reported gas units are MCF (thousand cubic feet)

• Data on website includes the highest-producing 70% of the fields in Colorado, which comprises 99.99% of the total oil and gas production in the state.

• Basins were assigned based on reported county and relating these to position on Basin map posted on Colorado Stratigraphy website

• Formation details reported were aggregated into 109 overall formations

o Where multiple formations reported on a single field in one reporting year, the first formation in list was taken


o For historic production, formations were assigned as follows:

• 1997-1998: For fields with production reported in prior or later years, formation showing greatest total production assigned to these years

• Production reported in 1999 and later with formation reported as “UNKNOWN” or “NOT COMPLETED” were omitted from the data


Log Cross Sections

These come from the 1977 Rocky Mountain Association of Geologists Special Publication 2 edited by Dennis Irwin, Chair of the RMAG Research Committee. Committee members include: Lou Bortz, Lionel Brenneman, John Chronic, William Clark, Harold Dunn, Thomas Fisher, Lyle Hale, Dennis Irwin, Roger Matuszczak, Daniel McClure, Cornelius (K) Molenaar, David Moore, Duane Mordock, Richard Pearl, Soli Shapurji, Robert Wellborn, William Whiteley, and John Wilson.


Structural Cross Sections

These come from a compilation by William Nesse, published by the Rocky Mountain Association of Geologists.


Stratigraphic Panels (Under Construction)

Bob is compiling panels of stratigraphic information along the Colorado Front Range tied directly to measured sections as indicated.  The stratigraphic panel along the Uinta Piceance and Eagle basins comes from the U.S. Geological Survey Map I-2184-A by S. Jackson and R. Johnson 1990.


Paleogeography Videos

These videos were made by concatenating Ron Blakey’s paleogeographic maps.


Interactive Geology Project Videos

These videos are provided courtesy of Paul Weimer and his team at University of Colorado, Boulder.  For more videos and additional information, see igp.colorado.edu







Many people have been involved in assembling this material. Jessica Don from the Colorado School of Mines helped build the chart; Teresa Hill and April Johnson helped organize and compile the graphics and to create the web media. James Hagadorn of the Denver Museum of Nature & Science provided encouragement and perspective. His efforts at establishing a regional research project on the drainage history of Colorado spurred this effort. Working with Chris Holm-Denoma at the US Geological Survey we are using detrital zircon dating and provenance studies to establish regional stratigraphic patterns and to integrate the evolution of Colorado’s strata with work done at Colorado College by Christine Siddoway and elsewhere in the Southwest led by George Gehrels and William Dickinson.


Many people have provided advice; a list that still grows. Your input is also welcome!


Stratigraphic guidance has been generously provided by:




























Presentations were made to the Colorado Scientific Society (January 2016), Rocky Mountain SEPM, USGS Seminar Series, and at the GSA Regional Meeting, Casper (Summer 2015).


Whereas every effort has been made to portray the stratigraphy comprehensively, there are various patterns and nuances that remain under discussion. We hope these charts and maps will continue to evolve with your and other colleagues' input. Together we hope to learn more about the evolution of Colorado’s landscapes and strata. Hence the chart will be updated; please note the date at the bottom left corner of the chart.


Bob Raynolds                                                                                                                         September 2016

James Hagadorn





Lon Abbott

Donna Anderson

Peter Barkmann

Paul Belanger

Karen Berry

Don Boyd

Bruce Bryant

Steve Cather

Jim Cole

Rex Cole

Marshall Deacon

Marieke Dechesne

Jessica Don

Sven Egenhoff

Eric Erslev

Emmett Evanoff

James Evans

Frank Ethridge

Robert Fillmore

Gary Gianniny

Robbie Gries

David Gonzales

Bill Hood



Chris Holm-Denoma

Karen Houk

Mark Izod

Sam Johnson

Ron Johnson

Craig Jones

James Kirkland

Mark Kirschbaum

Karl Kellogg

Mark Kirschbaum

Louise Kitley

Eric Leonard

Michael Lewin

David Lindsey

Tyler Lyson

Ian Miller

Vince Matthews

Ian Miller

Scott Minor

Paul Myrow

Bill Nesse

Piret Plink-Bjorklund

Barney Poole



Libby Preuher

Don Rasmussen

Larry Rasmussen

Samantha Richards

Peter Robinson

Cal Ruleman

Charlie Sandberg

Matt Sares

Joe Sertich

Ralph Shroba

Bruce Shumacher

Christine Siddoway

Beth Simmons

Steve Sonnenberg

Ned Sterne

Lou Taylor

Paul Umhoefer

John Warme

John Webb

Bob Weimer

Paul Weimer

Jeremy Workman


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Colorado Stratigraphy