Earth Science Frontiers ›› 2020, Vol. 27 ›› Issue (4): 244-254.DOI: 10.13745/j.esf.sf.2019.8.20

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Discovery and geological significance of gold-silver bearing minerals and tellurides in the Yongxin gold deposit in the northeastern Great Xing'an Range

LI Chenglu1(), YU Yuanbang1, YUAN Maowen2, LI Shengrong2, XU Wenxi1, ZHU Jing3, LI Shisheng2   

  1. 1. Heilongjiang Institute of Geological Survey, Harbin 150036, China
    2. China University of Geosciences(Beijing), Beijing 100083, China
    3. Bureau of Geology and Mineral Resource of Heilongjiang Province, Harbin 150036, China
  • Received:2019-01-15 Revised:2019-05-21 Online:2020-07-25 Published:2020-07-25

Abstract:

The Yongxin gold deposit, formed during the Early Cretaceous, is an epithermal type deposit. We performed EPMA analysis which showed that the Au-Ag bearing minerals in the Yongxin gold deposit contained 65.092%-90.713%(mass fraction) Au (averaged at 83.942%) and 5.652%-16.632% Ag (averaged at 11.285%). The gold deposit mainly contained 10-20 μm natural gold and electrum grains (fineness ranged from 870.2 to 941.3 with an average of 881.1) occurring in inclusions, intergranular pores and crevices. Telluride is mainly composed of tetradymite, petzite, hessite and altaite. Hessite (5-20 μm) is the most common telluride in the Yongxin gold deposit, occurring in the interior or fracture of pyrite grains often associated with natural gold and galena. We studied telluride assemblage, fineness of gold and Te/Au values at different elevation. The results showed that the lgf(Te2) and lgf(S2) values during telluride formation ranged from -15.2 to -9.4 and from -16.7 to -14.0, respectively, which revealed that the mineralization in the Yongxin gold deposit is associated with volcanic or subvolcanic hydrothermal fluid and with characteristics of shallow mineralization, suggesting great mineralization potential still at depth.

Key words: chemical components, gold-silver bearing minerals, tellurides, Yongxin gold deposit, Northeast Great Xing'an Range

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