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Geology and genesis of the gold deposits of the Qinling orogen, China
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
Mao Jingwen, Richard Goldfarb, Yumin Qiu, Zhang Zhaochong, Xu Wenyi
The Xiaoshan area is a structural dome bounded by the Sanmenxia-Baofeng fault to the north and the Jiaohe fault to the south, and Mesozoic-Cenozoic fault bounded basins to the northwest and southeast. The dome has a core of Archean basement rocks, which is surrounded by Proterozoic metamorphic rocks. Auriferous quartz veins are developed along fractures that are discordant to the boundaries between the rock units of the dome. Orogenic gold deposits in this area are commonly small, but with high grade. Lead-, zinc- and copper-bearing sulfide minerals are the main metallic phases, with anomalous tungsten and molybdenum, in the ores. Arsenic, Sb, and Hg are typically at background concentrations.
Investigation based on quantified spatial relationships between gold deposits and ore genesis factors in northeast Malaysia
Published in Journal of Spatial Science, 2021
Mathew Gregory Tagwai, Onimisi A. Jimoh, Kamar Shah Ariffin, Mohd Firdaus Abdul Razak
Orogenic gold deposits refer to an identified group of gold deposits that are controlled by a set of related factors (Groves et al. 1998, Fielding et al. 2018). These groups of gold deposits occur within areas of accretionary or collisional orogens of all ages. Hydrothermal fluids originating from igneous activities beneath the earth surface formed the orogenic gold deposits (Block et al. 2000, Spence-Jones et al. 2018). The primary host of these deposit types includes Precambrian greenstone belts and Precambrian–Phanerozoic accretionary sedimentary belts. A predictive structural pattern is also a typical characteristic of these deposit types (Weinberg et al. 2004). Some proven areas of occurrence include the southern Gondwana margin, the Paleo-Tethys Ocean (Paleozoic) and the circum-Pacific accreted terranes (Mesozoic–Tertiary) (Goldfarb and Groves 2015a).
Predicting grade-tonnage characteristics of undiscovered mineralisation: application of the USGS Three-part Undiscovered Mineral Resource Assessment to the Sandstone Greenstone Belt of the Yilgarn Block, Western Australia
Published in Applied Earth Science, 2020
Rhys S. Davies, Richard Schodde, John P. Sykes, David I. Groves, Allan Trench, Michael Dentith
Although the MinEx database represents a thorough review of historic production, resources and reserves, many of the gold deposits featured in the grade-tonnage models remain uneconomic to mine. These deposits are included to provide a comprehensive distribution of potential deposit sizes, since many factors beyond grade and tonnage can influence whether a deposit is developed into a mine (such as depth, commodity price, mineral policy and land access), meaning total historic production of mines is not necessarily equal or representative of future production (Ellefsen 2019). At times, deposits are reported under different names and occasionally production has been aggregated into a broad mining camp. Variations in grade-tonnage models due to modern mining techniques can also influence the results of a Three-Part Assessment. With the development of modern mining techniques average grades of orogenic gold deposits have dropped drastically, which in-turn has increased average ore tonnage (Davies et al. 2019b). Owing to these considerations, all deposits in the database were subjected to a comprehensive data-cleansing and validation process. Considerable effort ensured consistency and comparability of reported gold grades and tonnages over time. Where possible, past production was attributed as contained gold, or at least combined with subsequently delineated resources, and resources are compared by selecting a common and consistently low cut-off grade where available.