Turquoise Ridge Mine

Humboldt County, Nevada, United States

GoldSilverArsenicBismuthTinLeadZincAntimonyMercuryBarium-BariteMolybdenumFluorine-FluoriteThalliumTelluriumCopperTungsten

⌖ Show on map USGS source ↗

Description

Edward Knight and Emmet Chase

Commodities

PrimaryGold, Silver

SecondaryArsenic

TertiaryBismuth, Tin, Lead, Zinc, Antimony, Mercury, Barium-Barite, Molybdenum, Fluorine-Fluorite, Thallium, Tellurium, Copper, Tungsten

Commodity typeB

Deposit

Deposit typeSediment-hosted Au; replacement

Model173: Sediment-hosted Au

Deposit sizeL

Ore controlEconomic amounts of gold are restricted to tabular sheet-like zones (termed "veins" by Joralemon) within the Getchell fault zone and within favorable calcareous lithologies.

Materials

Ore mineralsGold, Silver, Electrum

GangueRealgar, Orpiment, Pyrite, Scheelite, Pyrrhotite, Arsenopyrite, Marcasite, Magnetite, Stibnite, Ilsemannite, Cinnabar, Hubnerite, Calcite, Chabazite, Sericite, Chlorite, Barite, Gypsum, Fluorite, Getchellite, Galkhaite, Laffittite, Arsenolite, Guerinite, Haidingerite, Pharmacolite, Weilite, Coloradoite, Bismuthinite, Cassiterite, Molybdenite, Ferrimolybdite, Galena, Sphalerite, Covellite, Chalcocite, Garnet, Epidote

Geology

Host rockShale,Limestone · "Preble Fm.", "Valmy Fm"

Associated rockGranodiorite · Osgood Mountains Pluton

StructureThe Turquoise Ridge deposit occurs on a north-east trending fault system that extends to the Getchell Main Pit where it intersects the main Getchell Fault Zone. To the north-east it heads towards the Chimney Creek orebody. The NNW trending faulting of the Getchell Fault Zone post dates east-west crossing structures, but pre-dates, or is contemporaneous with, north-east and north-west trending structures and joint swarms. These north-east and north-west cross-structures tend not to be displaced, but commonly coalesce with the Getchell Fault Zone, favouring the interpretation that they are largely contemporaneous. They also appear to exert a major control on ore deposition. The older east-west fault and joint sets produce graben structures throughout the mine area, some of which drop the Valmy Formation down to become juxtaposed with the Comus Formation.\nGold mineralization is generally found at the intersection of a number of high-angle and low-angle fault sets. The low-angle faults and associated folds are the result of Devonian and Permian-age compressional events and the higher angle faults and fracture sets formed during Tertiary extension. Mineralization is both structurally and stratigraphically controlled. \n, Getchell Fault Zone, Osgood Mountains Pluton, The Getchell fault is a zone of overlapping fractures which have an overall strike of N10W. Hotz and Willden (1964) offer evidence for up to 3500 feet of left lateral strike slip displacement and only a relatively small amount of dip slip movement along the Getchell fault. McCollum and McCollum (1991) indicate that the sense of movement on the Getchell fault is right lateral.

AlterationAlteration comments: there is a metamorphic aureole around the Osgood Mountains granodiorite which has produced in the surrounding shaly rocks a mineral assemblage consisting of cordierite-, biotite-, and andalusite-hornfels. Locally limy beds are recrystallized and calc-silicate minerals are developed. Hydrothermal alteration consists chiefly of decarbonatization accompanied by silicification in the limestone beds. Cordierite, andalusite, and biotite of the metamorphic aureole are altered to sericite and/or chlorite. Igneous dikes and portions of the main stock are altered such that plagioclase is altered to sericite and kaolinite and biotite is altered to sericite, chlorite, and pyrite.

Economic & production

Development statusProducer

Production years1938-2006

First production1938

Last production2006

Discovery year1933

Identification

Deposit ID10310336

Alternate namesPowder Hill, Bud Hill, A Zone, Shaft Zone, N Beds, considered to be a satellite deposit of Getchell Gold Mines

RegionNA

Data scoreA

Coordinates41.20989, -117.25874

References

Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Significant deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 90-206A, 33 p.; 98-206B. one 3.5 inch diskette.John Muntean,2005, Turquoise Ridge Deposit: Basin Margin Control on Gold Grade, abstract, Winnemucca GSN meeting, Aug.17, 2005.Barrick Gold Corporation, Nevada Mine Tour, September 2006. online presentation on website.