Description
John J. Holbrock (Claimant)
Commodities
PrimarySilver, Gold, Lead
SecondaryCopper
TertiaryZinc, Antimony
Commodity typeM
Deposit
Deposit typeVein
Deposit sizeS
Ore controlNe-Trending Fault/Fracture Transverse To Lake City Caldera Ring Fault But Subparallel To Trend Of Pre-Lake City Caldera Eureka Graben
Materials
Ore mineralsGalena, Sphalerite
GangueQuartz
Geology
Host rockVolcanic Breccia (Agglomerate),Rhyolite · Picayune Megabreccia Member Of Sapinero Mesa Tuff
Associated rockRhyolite · Eureka Member Of Sapinero Mesa Tuff
StructureSan Juan Volcanic Field, San Juan Depression, San Juan-Uncompahgre Calderas, Lake City Caldera, Eureka Graben
Tectonic settingCentral Cordillera (Southern Rocky Mtns)
Economic & production
Development statusPast Producer
Last production1968
Discovery year1876
Identification
Deposit ID10014729
MRDS IDD011628
Alternate namesPatented Claims: Big Casino No. 2, MS 69a, Big Casino No. 2 Mill Site, MS 69b, Big Casino No. 2, MS 836
RegionNA
Data scoreB
Coordinates38.01028, -107.43313
References
IRVING, J.D., AND BANCROFT, HOWLAND, 1911, GEOLOGY AND ORE DEPOSITS NEAR LAKE CITY, COLORADO: USGS BULL. 478, P. 81.SLACK, J.F., 1980, MULTISTAGE VEIN ORES OF THE LAKE CITY DISTRICT, WESTERN SAN MOUNTAINS, COLORADO: ECON. GEOLOGY, V. 75, NO. 7, P.963-991.LIPMAN, P.W., 1976, GEOLOGIC MAP OF THE LAKE CITY CALDERA AREA, WESTERN SAN JUAN MOUNTAINS, SOUTHWESTERN COLORADO: USGS MAP I-962.COLORADO DIV. MINES INF. REPTS. AND ANNUAL OPERATOR REPTS.BLM MINERAL SURVEY MS 69A&B, 836COLORADO DIV. MINES ANNUAL OPERATOR REPTS.