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Geoscience ›› 2019, Vol. 33 ›› Issue (02): 251-261.DOI: 10.19657/j.geoscience.1000-8527.2019.02.01

• Ore Deposits and Petrology •     Next Articles

Geological Characteristics, Metallogenic Age and Genesis of Niumaoquan East Gold Deposit in the Western North Qilian

FAN Xinxiang(), KONG Weiqiong, YANG Zhenxi, ZHAO Jichang, ZHOU Shuming   

  1. Fourth Institute of Geological and Mineral Exploration of Gansu Provincial Bureau of Geology and Mineral Resources, Jiuquan,Gansu 735000,China
  • Received:2018-10-28 Revised:2019-02-25 Online:2019-05-08 Published:2019-05-08

Abstract:

Niumaoquan East gold deposit is located at the intersection area where the North Qilian orogenic belt and the Altun fault converged, which is known as the “Golden Triangle” in Northwest China. Niumaoquan East gold deposit is a newly discovered gold deposit in the area controlled by fragile-ductile faults. The gold ores occurred in EW-striken ductile faults developed in the andesite tuff and andesite lavas of Yingou Group. Gold mineralization apparently was controlled by ductile faults, featured by multistage mineralization. Most of gold was deposited at sulfide-quartz-gold stage. The wall rocks around gold lodes and ores have shown intensive hydrothermal alteration, gold mineralization is mainly related with silicification. Homogenization temperatures of fluid inclusions for the quartz in gold ores are 112-191 ℃, the salinity is 0.35%-7.86% with an average of 4.77%, the density is 0.92-0.96 g/cm3 with the average of 0.95 g/cm3, all of which are showing typical characteristics of epithermal gold deposits. The40Ar-39Ar dating of the sericite collected from wall rocks yields plateau age of (296.7±2.8)Ma corresponding to the inner continental extension stage of the North Qilian belt. The geological characteristics and metallogenic age of Niumaoquan East gold deposit is quite similar with that of Hanshan gold deposit located in nearby area, both of the two deposits are controlled by the same NWW trending of ductile-brittle fault zones, should belong to low-sulfidation epithermal deposit formed in late Variscan period. The discovery of the gold deposit and the study on the genesis are of great significance for guiding regional prospecting.

Key words: Niumaoquan East gold deposit, geological characteristics, ore genesis, western section of North Qilian

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