Jacobsen Ranch, Clear Creek Co., Colorado, USA
Latitude & Longitude (WGS84): | 39° 42' 34'' North , 105° 24' 1'' West |
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Latitude & Longitude (decimal): | 39.70965,-105.40053 |
GeoHash: | G#: 9xj1csctm |
Locality type: | Ranch |
Köppen climate type: | Dfb : Warm-summer humid continental climate |
Ref.: Meeves, H., et al (1966), Reconnaissance of beryllium-bearing pegmatite deposits in six western states, US Bur. Mines Info. Circ. 8298: 24 (Table A-1).
A pegmatite deposit located in the SW¼sec. 12, T.4S., R.72W.
Mineralization is a zoned pegmatite Core zone: 2 foot (60 cm) quartz pegmatite; ntermediate zone: 3 foot (90 cm) microcline-quartz-tourmaline pegmatite; border zone: 3 inch (7.5 cm) aplitic pegmatite, concordant in biotite gneiss.
Mineral List
2 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: 2207731 | Quartz-feldspar gneiss and horneblende gneiss Age: Proterozoic (1600 - 2500 Ma) Description: Interlayered dark-gray and light-gray, well-foliated quartz-feldspar gneiss (Xf) and hornblende-plagioclase gneiss and amphibolite (Xh), including amphibolite, in approximately equal amounts. Some areas in Squaw Pass 7.5-minute quadrangle are equivalent to the mixed layered gneiss unit (Xlg) of Evergreen quadrangle 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: 2855882 | Felsic and hornblendic gneisses, either separate or interlayered Age: Proterozoic (1600 - 2500 Ma) Description: Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks Lithology: Major:{gneiss}, Minor:{metabasalt,metagraywacke} 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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