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Croesus, Georgetown District, Clear Creek Co., Colorado, USA

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Latitude & Longitude (WGS84): 39° 41' 44'' North , 105° 43' 23'' West
Latitude & Longitude (decimal): 39.69556,-105.72305
Köppen climate type:Dfc : Subarctic climate

Commodities (Major) - Gold; (Trace) - Silver, Lead
Development Status: Past Producer

Commodity List

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

Mineral List

6 valid minerals.

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

Holocene - Middle Pleistocene
0 - 0.781 Ma

ID: 2211958
Landslide deposits

Age: Pleistocene (0 - 0.781 Ma)

Description: Deposits of unsorted and unstratified debris, on slopes or at base of slopes, that are commonly characterized by hummocky topography. Many of the landslides and landslide deposits form on unstable slopes that are underlain by shale, siltstone, and claystone on east flank of hogback belt and on slopes of North Table Mountain and South Table Mountain near Golden. Younger deposits are commonly bounded upslope by crescent-shaped headwall scarps and downslope by lobate toes. Unit locally includes material displaced chiefly by rotational rock slides, rotational earth slides, debris slides, earth flows, and earth slide–earth flows as defined by Varnes and Cruden (1996). Some deposits probably are formed by translational slides and rock or earth creep. Sizes and lithologies of clasts and grain-size distributions of matrices of these deposits reflect those of the displaced bedrock units and surficial deposits. Landslide deposits are prone to continued movement or reactivation due to natural, as well as human-induced, processes. Deposits in mountainous terrain derived from Precambrian quartz-feldspar gneiss (Xf) and biotite gneiss (Xb) locally contain blocks of rock as long as several meters. Landslide deposits derived from Pierre Shale (Kp), Laramie Formation (Kl), and Denver Formation (bKd) are rich in clay. Some of this clay is expansive and locally may have high potential for shrinking and swelling (Shroba, 1982). Deposits on gentle slopes along and east of hogback belt locally include minor sheetwash and creep-deformed deposits. Deposits in mountains locally include minor rock-fall deposits. Estimated thickness 5–50 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]

1600 - 2500 Ma

ID: 3186950
Paleoproterozoic crystalline metamorphic rocks

Age: Proterozoic (1600 - 2500 Ma)

Lithology: Orthogneiss/paragneiss

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]

1600 - 2500 Ma

ID: 2831994
Biotitic gneiss, schist, and migmatite

Age: Proterozoic (1600 - 2500 Ma)

Description: Locally contains minor hornblende gneiss, calc-silicate rock, quartzite, and marble. Derived principally from sedimentary rocks

Lithology: Major:{biotite gneiss,schist,migmatite}, Minor:{gneiss,calc silicate schist,marble}

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]

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.
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