Coon Gulch Clay Pits, Lower Clear Creek Area, Jefferson Co., Colorado, USA
|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|
REF:Deposit:: LEROY, 1944, COLO. SCH. MINES DSC. THESIS
Deposit:: CONSV. DIV. COMP. DATE, 3,64
Commodities (Major) - Clay
Development Status: Occurrence
Host Rock Unit: Dakota Formation
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
1 valid mineral.
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 Macrostrat.org
0.0117 - 2.588 Ma
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. 
0.126 - 0.781 Ma
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. 
|Paleocene - Late Cretaceous|
56 - 100.5 Ma
|Denver and Arapahoe Fms|
Age: Phanerozoic (56 - 100.5 Ma)
Stratigraphic Name: Denver Formation; Arapahoe Formation
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. 
201.3 - 252.17 Ma
|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.