SUPPORT US. Covid-19 has significantly affected our fundraising. Please help!
Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsBooks & Magazines
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryMineral Photography

Coon Gulch Clay Pits, Lower Clear Creek Area, Jefferson Co., Colorado, USA

This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84): 39° 43' 8'' North , 105° 11' 30'' West
Latitude & Longitude (decimal): 39.71889,-105.19167
Köppen climate type:Dfb : Warm-summer humid continental climate

Deposit:: CONSV. DIV. COMP. DATE, 3,64
Commodities (Major) - Clay
Development Status: Occurrence
Host Rock Unit: Dakota Formation

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

1 valid mineral.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

0.0117 - 2.588 Ma

ID: 2443449
Slocum Alluvium

Age: Pleistocene (0.0117 - 2.588 Ma)

Description: Bouldery cobble gravel near mountain front, decreases in grain size eastward away from mountains. Much calcium carbonate (CaCO3) in upper part where not removed by erosion. Many unsound stones. Thickness generally less than 7.6 m. Forms gently sloping surfaces 24 to 36 m above present streams.

Reference: Trimble, D.E., M.N. Machette. Geologic Map of the Greater Denver Area, Front Range Urban Corridor, Colorado. U.S. Geological Survey Geologic Investigations Series I-856-H. [64]

Middle Pleistocene
0.126 - 0.781 Ma

ID: 2207043
Slocum Alluvium

Age: Pleistocene (0.126 - 0.781 Ma)

Stratigraphic Name: Slocum Alluvium

Description: Deposited in piedmont east of mountain front where it consists of silty sand and sandy to clayey silt in upper part and mostly pebbly to cobbly gravel interbedded with pebbly to clayey silt in lower part. Some of the silt and clay within upper part of unit may be of eolian origin (Reheis, 1980). Soils formed in upper part of unit have A/Bt/Bk/K/Bk profiles with stage II–III carbonate morphology. Amount of cobbles and boulders in lower part of unit decreases with increasing distance east of mountain front. Unit Qs consists of terrace, pediment, and valley-fill deposits locally at two levels, about 24–30 and 37–45 m above major streams near the hogback belt. The Slocum is considered to be about 240 ka (Madole, 1991a), based on a uranium-series age of 190±50 ka near Canon City, Colo. (Szabo, 1980). Based on tentative correlation with marine oxygen isotope stages and a nonlinear rate of stream incision in the Denver area since the deposition of the 640-ka Lava Creek B tephra, younger deposits of unit Qs may have accumulated between about 300 and 220 ka, and older deposits may have accumulated between about 390 and 320 ka (see discussion in section, Post-Laramide Cenozoic History of the Front Range). Thickness commonly about 3–6 m; locally as much as 12 m

Reference: Kellogg, K.S., Shroba, R.R., Bryant, Bruce, and Premo, W.R. Geologic Map of the Denver West 30' x 60' Quadrangle, North- Central Colorado. USGS Geologic Investigations Series 3000. [35]

Paleocene - Late Cretaceous
56 - 100.5 Ma

ID: 2954406
Denver and Arapahoe Fms

Age: Phanerozoic (56 - 100.5 Ma)

Stratigraphic Name: Denver Formation; Arapahoe Formation

Description: Sandstone, mudstone, claystone, and conglomerate; Denver is characterized by andesitic materials

Lithology: Major:{sandstone,mudstone,conglomerate}, Minor:{claystone,andesite}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

201.3 - 252.17 Ma

ID: 3191821
Mesozoic sedimentary rocks

Age: Triassic (201.3 - 252.17 Ma)

Lithology: Sedimentary rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
Mineral and/or Locality  
Mindat Discussions Facebook Logo Instagram Logo Discord Logo is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © and the Hudson Institute of Mineralogy 1993-2020, except where stated. Most political location boundaries are © OpenStreetMap contributors. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: November 30, 2020 21:20:07 Page generated: February 17, 2018 04:07:25
Go to top of page