CUI Xiao-ling1,3, LIU Wen-yuan1,2, LIU Yu1, LI Xiao-min1
(1. Collage of Zijin Mining, Fuzhou University, Fuzhou 350108, China;
2. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100871, China;
3. China University of Geoscience (Beijing), Beijing 100083, China)
Abstract: With the expansion of the open-pit of Zijinshan Au-Cu deposit, many geological features closely related to the genesis of deposit have been exposed. The fault structures, mineralization and alteration zones of the Zijinshan Mine have been investigated. It suggests that adjacent to a volcanic pipe and from north to south and, alteration zones vary from a sericite+dickite alteration zone to a dickite+alunite alteration zone, then to a dickite+limonite zone and a silicified zone. The major mineral assemblages within each alteration zones are respectively: pyrite, bornite, enargite and digenite; pyrite, digenite, covellite, bornite and enargite; limonite, goethite and native gold; and, pyrite, bornite, enargite and digenite. The spatial distribution of mineral assemblages in the horizontal direction contain major copper minerals varying from bornite-dominated to digenite-dominated ore. Vertically, the mineral assemblages change from the native gold and limonite in the upper levels changing to bornite and digenite and to covellite at lower levels. Accordingly, these characteristics of mineral distribution are controlled by fault fractures and the volcanic pipe. Both the alteration zoning and spatial distribution of mineral assemblages indicate, adjacent to the volcanic pipe, the sulfur fugacity and oxygen fugacity are increasing with hydrothermal mineralisation. Small amounts of tin-bearing minerals with indicating significance also occur in the ore. Above all, the geological features suggest that Zijinshan Au-Cu deposit is the result of a multi-stage hydrothermal superimposition. The enrichment of gold and the boundary between gold and copper deposits is controlled by the intersection of the north-east fracture zones and north-west fracture zones.
Keywords：Zijinshan Au-Cu deposit; alteration zone; fault structure; mineral assemblage; sulphur fugacity
Email: xlcui2014@163.com
ACTA MINERALOGICA SINICA Vol. 35, No. 2, 2015, Page 167-177
