Gem (Freighter's Friend), Idaho Springs District, Clear Creek Co., Colorado, USA
| Latitude & Longitude (WGS84): | 39° 45' 40'' North , 105° 30' 51'' West |
|---|---|
| Latitude & Longitude (decimal): | 39.76111,-105.51417 |
| Köppen climate type: | Dfc : Subarctic climate |
REF USGS PROF PAPER 223 PLATE 3
Commodities (Major) - Gold; (Trace) - Silver
Development Status: Past Producer
Commodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
12 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 Macrostrat.org
| Paleoproterozoic 1600 - 2500 Ma ID: 2207492 | Quartz-feldspar gneiss Age: Proterozoic (1600 - 2500 Ma) Description: Gray, dark-gray, white, pinkish-gray, and tan, moderately foliated to well-foliated, layered, fine- to coarse-grained (mostly medium grained) quartz-plagioclase-microcline-biotite gneiss. Proportion of minerals varies widely. Layers typically 10 cm to several tens of meters thick and commonly wavy. Locally contains layers of foliated monzogranite and granodiorite. May contain minor, thin layers of hornblende gneiss and amphibolite. Commonly migmatitic. U-Pb date on weakly foliated rock of monzogranitic composition in northwestern part of Indian Hills 7.5-minute quadrangle is 1,776±4 Ma. Weathers tan to pinkish tan in rounded outcrops. Crops out widely throughout map area 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] |
| Paleoproterozoic 1600 - 2500 Ma ID: 2957947 | 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] |
| Paleoproterozoic 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] |
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