The geology and ore deposits of Goldfield, Nevada

Ransome, Frederick Leslie; Emmons, William H.; Garrey, G. H.

doi:10.3133/pp66

Cited by 32 publications

(51 citation statements)

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“…3A, label D) and extends east-southeast from the main ore body for a distance of at least 8-10 km. Within the transverse zone, there is a series of en echelon, east-west-striking silica ridges, which were referred to as "ledges" in Ransome (1909). The silica ledges connect with northwest-striking hydrothermal chalcedony veins, indicating hydraulic linkage between west-northwest-striking faults and fractures within the transverse zone during hydrothermal alteration (Berger et al, 2005).…”

Section: Goldfi Eldmentioning

confidence: 99%

Crustal controls on magmatic-hydrothermal systems: A geophysical comparison of White River, Washington, with Goldfield, Nevada

et al. 2007

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The White River altered area, Washington, and the Goldfi eld mining district, Nevada, are nearly contemporaneous Tertiary (ca. 20 Ma) calc-alkaline igneous centers with large exposures of shallow (<1 km depth) magmatic-hydrothermal, acid-sulfate alteration. Goldfi eld is the largest known high-sulfi dation gold deposit in North America. At White River, silica is the only commodity exploited to date, but, based on its similarities with Goldfi eld, White River may have potential for concealed precious and/or base metal deposits at shallow depth. Both areas are products of the ancestral Cascade arc. Goldfi eld lies within the Great Basin physiographic province in an area of middle Miocene and younger Basin and Range and Walker Lane faulting, whereas White River is largely unaffected by young faults. However, west-northwest-striking magnetic anomalies at White River do correspond with mapped faults synchronous with magmatism, and other linear anomalies may refl ect contemporaneous concealed faults. The White River altered area lies immediately south of the west-northwest-striking White River fault zone and north of a postulated fault with similar orientation. Structural data from the White River altered area indicate that alteration developed synchronously with an anomalous stress fi eld conducive to left-lateral, strike-slip displacement on west-northwest-striking faults. Thus, the White River alteration may have developed in a transient transtensional region between the two strikeslip faults, analogous to models proposed for Goldfi eld and other mineral deposits in transverse deformational zones. Gravity and magnetic anomalies provide evidence for a pluton beneath the White River altered area that may have provided heat and fl uids to overlying volcanic rocks. East-to eastnortheast-striking extensional faults and/or fracture zones in the step-over region, also expressed in magnetic anomalies, may have tapped this intrusion and provided vertical and lateral transport of fl uids to now silicifi ed areas. By analogy to Goldfi eld, geophysical anomalies at the White River altered area may serve as proxies for geologic mapping in identifying faults, fractures, and intrusions relevant to hydrothermal alteration and ore formation in areas of poor exposure.

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Section: Goldfi Eldmentioning

confidence: 99%

Crustal controls on magmatic-hydrothermal systems: A geophysical comparison of White River, Washington, with Goldfield, Nevada

et al. 2007

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“…Arsenic, lead, molybdenum, and mercury clearly reflect the small quantities of enargite, galena, molybdenite, and cinnabar observed in the cap, but the mineralogic residence of bismuth and thallium is uncertain. However, bismuthinite and other bismuth-bearing minerals are characteristic of gold-bearing advanced argillic zones (e.g., Goldfield, Nevada; Ransome, 1909).…”

Section: Soil Geochemistrymentioning

confidence: 99%

The porphyry gold deposit at Marte, northern Chile

Vila¹,

Sillitoe²,

Betzhold³

et al. 1991

Economic Geology

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A porphyry gold deposit has been documented for the first time at Marte in the Maricunga belt of the Andean Cordillera, northern Chile. Exploration conducted from 1981 through 1987 resulted in definition of 66 metric tons of contained gold. The deposit entered production in late 1989 as an open-pit, heap leach operation. The gold deposit is part of a linear, calc-alkaline volcanoplutonic arc constructed during the mid-to late Miocene as eastward-directed subduction was shallowing. The consequent compression of continental basement underlying the deposit and its environs created a series of high-angle, reverse faults. Stock emplacement and gold mineralization took place within a coeval andesitic stratovolcano at 13 to 14 Ma. The hornblende-biotite diorite stock is subdivided into three phases: two mineralized porphyries and a weakly porphyritic, late mineralization microdiorite. Much of the microdiorite constitutes the matrix of an intrusion breccia, which is transected locally by a closely related hydrothermal breccia. Gold mineralization is coincident with a stockwork of quartz veinlets surrounded by chloritesericite-clay alteration of intermediate argillic type. Pyrite and iron oxides are both present in dominantly disseminated form, with each making up as much as 10 vol percent of the rock.Hematite exceeds magnetite in abundance and was generated in large part by hypogene martitization. Minor chalcopyrite and even lesser quantities of molybdenite, bornitc, tennantite, and enargite also occur. Gypsum after anhydrite commonly exceeds 5 vol percent and calcite and tourmaline exist as traces. Isolated remnants of hydrothermal biotite and alkali feldspar attest to the former presence of K silicate alteration, which is believed responsible for introduction of much of the veinlet quartz, magnetite, and gold. Chlorite-dominated alteration affected the late-stage microdiorite and its associated breccias. An erosional remnant of the andesitic volcanic roof to the stock is largely replaced by a chalcedony-and alunite-rich advanced argillic assemblage, which is part of a formerly more extensive tabular alteration zone. Abundant pyrite, gypsum, native sulfur, and barite and trace amounts of enargite and subeconomic gold are present in this advanced argillic cap.The relative impermeability of the cap caused development of an inverted supergene profile in which sulfide-bearing ore is underlain by jarositic leached ore. The steep, elongate orebody is made up of both ore types, which do not differ in gold content. However, the hypogene copper content, about 550 ppm, was more than halved by supergene oxidation. The gold ore is poor in silver (Ag/Au --0.44), but highly anomalous in molybdenum as well as copper and weakly anomalous with respect to lead, arsenic, and mercury. The advanced argillic cap is marked by pronounced Au, Bi, Hg, T1, Pb, Mo, and As anomalies, which contrast with a broad zinc halo to the orebody.Preliminary fluid inclusion studies suggest that the auriferous stockwork is a product of boiling fluids which ran...

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“…They form prominent outcrops, termed "ledges" by Ransome (1909). The remainder of the hydrothermally altered area consists of argillized rocks.…”

Section: Characteristics Of the Samplesmentioning

confidence: 99%

The geology and ore deposits of Goldfield, Nevada

Cited by 32 publications

References 0 publications

Crustal controls on magmatic-hydrothermal systems: A geophysical comparison of White River, Washington, with Goldfield, Nevada

Crustal controls on magmatic-hydrothermal systems: A geophysical comparison of White River, Washington, with Goldfield, Nevada

The porphyry gold deposit at Marte, northern Chile

Geochemical data for gold-bearing rocks from the Goldfield mining district, Nevada

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