Potosi & Cross Mines, Caribou District, Boulder Co., Colorado, USA
|Latitude & Longitude (WGS84):||39° 58' 44'' North , 105° 35' 9'' West|
|Latitude & Longitude (decimal):||39.97889,-105.58583|
|Köppen climate type:||Dfc : Subarctic climate|
REF:Deposit:: MOORE AND OTHERS, 1957, USGS BULL. 1030-N, P. 547 AND PL. 35.
Deposit:: CONSV. DIV. COMP. DATE, 10,62
Commodities (Major) - Silver
Development Status: Producer
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
10 valid minerals.
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
|Bartonian - Maastrichtian|
37.8 - 72.1 Ma
|Laramide intrusive rocks|
Age: Phanerozoic (37.8 - 72.1 Ma)
Description: Mainly intermediate to felsic compositions; some mafic
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. 
|Paleocene - Late Cretaceous|
56 - 100.5 Ma
|Rocks of Montezuma stock and vicinity, older felsic to intermediate porphyries of alkali-calcic group|
Age: Phanerozoic (56 - 100.5 Ma)
Description: Large stocks, adjacent smaller bodies, and dikes in Nederland area and in southern Empire and northern Georgetown 7.5-minute quadrangles. Includes the Caribou, Bryan Mountain (also called Eldora), and Apex stocks. Includes monzogranite, monzogranite porphyry, biotite-hornblende±pyroxene monzogranite (Gable, 1969), and granodiorite (Ed Dewitt, written commun., 2007). K-Ar age of Caribou stock is 68.2±4.1 Ma on hornblende and 65.5±2.4 Ma on biotite (Marvin and others 1989). K-Ar age on Bryan Mountain stock is 60.6±1.8 Ma on biotite (McDowell, 1971; Marvin and others, 1974)
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. 
1600 - 2500 Ma
|Paleoproterozoic crystalline metamorphic rocks|
Age: Proterozoic (1600 - 2500 Ma)
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.