Выпуск 9
Автор(ы):Keith Bettles
Издание:Economic geology, 2002 г., 24 стр.
Exploration and geology, 1962 to 2002, at the Goldstrike Property, Carlin Trend, Nevada

The Goldstrike property, located in the Carlin Trend in Nevada, contains a diverse group of Carlin deposits, including some of the largest and highest grade examples known. The largest deposit, Betze-Post, has a gold endowment of approximately 1,250 metric tons (t) Au, and the Meikle deposit, which contains 220 t Au, has a grade of 24.7 g/t Au. Goldstrike is part of the larger Blue Star-Goldstrike subdistrict, which has an areal extent of 58.5 by 2 km and a total gold endowment of 1,970 t. The first discovery of gold at Goldstrike was in 1962. Subsequent exploration culminated in the discovery in 1986 of large high-grade orebodies beneath smaller, lower grade orebodies. Exploration over a 40-yr period has relied on the evolution in understanding of geology and ore controls, supported by the application of geochemical and geophysical exploration techniques.

ТематикаПолезные ископаемые
Выпуск 105
Автор(ы):Annick Chouinard, Carolina Michelin de Almeida, Charles Weakly, Gema Ribeiro Olivo, Glenn Poirier
Издание:Economic geology, 2010 г., 34 стр.
Mineral paragenesis, alteration, and geochemistry of the two types of gold ore and the host rocks from the carlin-type deposits in the southern part of the Goldstrike Property, Northern Nevada: implications for sources of ore-forming elements, ore genesis

This study was undertaken to characterize the mineral paragenesis and metal zoning at the property scale, evaluate the potential sources of ore-related metals, quantify the relationship between intensity of alteration and gold grade, and propose a comprehensive genetic model for the Carlin-type Au deposits at the southern part of the Goldstrike property, Nevada.

Mineralogy, textural relationships, whole-rock composition, and spatial distribution of the studied samples revealed two types of gold ore: Ore I and II. The former, which is hosted by the Roberts Mountains and Rodeo Creek Formations, and the Wispy, Planar, and Upper Mud units of the Popovich Formation, is the most abundant and widespread in the property. Ore I is characterized by intense hydrothermal alteration (e.g., carbonate dissolution, silicification, and precipitation of pyrite) and high amounts of trace elements (e.g., Ag, As, Au, Ba, Cd, Cu, Hg, Mo, Ni, S, Sb, Se, Te, Tl, and Zn). On the other hand, Ore II, which is hosted in the Wispy, Planar, and Soft Sediment Deformation units of the Popovich Formation, is mainly confined to the central-north-northwest portion of the Screamer deposit and is weakly altered with low concentration of trace elements. Both Ores I and II contain similar average concentrations of Au in whole rock (14 and 19 g/t Au, respectively) and in pyrite (290 and 540 ppm, respectively); however, auriferous pyrite from Ore I has higher trace element (As, Ag, Cu, Hg, Ni, Sb, Se, and Tl)/Au ratios than Ore II.

ТематикаПолезные ископаемые
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