Goldbanks Gold Deposit

Pershing County, Nevada, United States

GoldSilverMercury

⌖ Show on map USGS source ↗

Description

Gary L. Grauberger

Commodities

PrimaryGold

SecondarySilver

TertiaryMercury

Commodity typeM

Deposit

Deposit typeHot-Spring Au-Ag

Model104: Hot-spring Au-Ag

Deposit sizeS

Orebody formblanket

Ore controlEpithermal mineralization is interpreted to have been formed by gold and silica-rich solutions ascending along steep fault structures until they encountered permeable clastic sediments along which the solutions migrated outwards to form a siliceous blanket-shaped deposit in the Main Zone measuring 2 km by 1 km and approximately 90 m thick. The predominant permeable host rock lithologies are a basal lithic sandstone (well-sorted litharenite) and an overlying polylithic breccia (mostly conglomeratic with abundant hydrothermal and tectonic brecciation). Overlying these two lithologies is a thick unit of lacustrine mudstones which appears to have acted as an impermeable cap for localizing silica and gold mineralization in the more permeable units below it. The structural axis and hydrothermal conduit for the Main Zone mineralization does not appear to have a surface expression; but drilling has outlined a major north-south zone about which the gold mineralization has spread laterally. Because the major gold resource has no surface expression, and Quaternary alluvium and basalts blanket much of the area, the presence and amount of any fault displacement of the ore zones is speculative.\nMineralization

Materials

Ore mineralsGold, Pyrite, Arsenopyrite, Marcasite, Goethite, Hematite, Cinnabar

GangueQuartz

Geology

Host rockSandstone,Sedimentary Breccia,Granite,Rhyolite,Tuff · "Havallah Sequence", "Koipato Group"

StructureAn extensive network of NNW-, NE-, and strong NW to almostE-W-trending faults dissect the property in the vicinity of the Main Zone. \n, Late Paleozoic rocks in the area are part of the allochthonous block of the Golconda thrust plate emplaced during the Sonoma Orogeny.

Tectonic settingTertiary strata were deposited into a rapidly subsiding basin which encompasses most of the Goldbanks area. Basin development coincided with the onset of Basin and Range faulting approximately 17 m.y. ago.

AlterationWidespread, pervasive silicification affects all rock units stratigraphically below the mudstone. Breccia units are most strongly silicified as is the lithic sandstone in some areas. Very fine-grained adularia accompanies silicification. Argillic alteration overprints the silica with illite as the main alteration clay mineral. Zones of intense iron oxidation (goethite and limonite) follow fractures and veins to depths as much as 365 meters below the surface. In the Main gold zone, a gray pervasive silicification resembling jasperoid is associated with gold mineralization, although open-space drusy quartz is also common.\nA thick layer of opaline sinter overlies the gold mineralized units and capping mudstone. The opalite hosted the mercury deposits in the area.

Economic & production

Development statusPast Producer

Discovery year1986

Identification

Deposit ID10310549

MRDS IDM060491

RegionNA

Data scoreB

Coordinates40.45823, -117.68429

References

Johnson, M. G., 1977, Geology and Mineral Deposits of Pershing County Nevada: NBMG Bull. 89, p. 56-57.Vanderburg, W.O., 1936, Reconnaissance of Mining Districts in Pershing County Nevada: USBM Information Circular 6902, P. 15.Dreyer, R. M., 1940, Goldbanks Mining District, Pershing County Nevada: NBMG Bull. 33, P. 28-30.Garside, L.J., 1984, Goldbanks Merger Mines-Field Examination and Sample Analysis, Pershing County, Goldbanks District: NBMG Unpublished File(Tingley).Bailey, E.H. & Phoenix, D.A., 1944, Quicksliver Deposits in Nevada: NBMG Bull. 41.Stone, Barton, Thomas, Dennis, Snider, Larry, McDermott, Ryan, and Nyman, Mark, 2000, The Goldbanks deposit, a recent discovery of disseminated gold in Tertiary volcaniclastics, Pershing County, Nevada, in Cluer, J.K., Price, J.G.,Struhsacker, E.M., Hardyman, R.F., and Morris, C.L., eds., Geology and Ore Deposits 2000: The Great Basin and Beyond: Geological Society of Nevada Symposium Proceedings, May 15-18, 2000, p. 289-303.Lovelock Review Miner. 2/18/99.Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States; Part A, Database description and analysis; part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.