LI Zhong-xuan1,2,3, LIU Yu-ping1*, YE Lin1, LIAO Zhen4, ZHANG Qian1,WANG Biao3
(1. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academic of Science,Guiyang 550081, China;
2. University of the Chinese Academy of Sciences, Beijing 100049, China；
3. 113 Geological Party, Guizhou Bureau of Geology and Mineral Exploration ＆ Development, Liupanshui 553001, China.;
4. Sinotech Minerals Exploration Co.,Ltd.Beijing 100012, China)
Abstract: Oolitic pyrite is one kind of feature minerals in Dulong Sn-Zn polymetallic deposit, Yunnan Province, China. In this paper, the micro-morphological characteristics of oolitic pyrite were studied by using field emission scanning electron microscope (SEM) and its chemical components were analyzed with electronic probe. These analytic results provid micro-scale evidences for the genesis of oolitic pyrite and its relationship with mineralization. The SEM results show that a lot of filaments, rhabdoids and spheroidites occur at micro fractures in the lamina of ooids. These micro-textures have similar morphology characteristics with micro-fossils occurring at exhalative hydrothermal sedimentary sulfide ore deposits, hot springs and hydrothermal vents under sea, indicating that their microbe genesis which might be related to exhalative hydrothermal sedimentation. The microbes might play a role to transform sulfide source, absorb metal elements and cement pyrite crystallites during pyrite ooids’ forming. In addition, the electronic probe results show that the pyrite ooids have a high concentration of Zn, suggesting that pyrite ooids might be a source providing some ore-forming elements such as S, Fe and Zn, etc. The edge of oodis is brighter than inner under micro-scope as the result of metasomatism. The characteristics of the concentration of Zn show a gradually decreasing trend from edge to center.
Keywords: oolitic pyrite; micro-fossils; hot-water sedimentation; source of ore-forming material; Dulong Sn-Zn polymetallic deposit
ACTA MINERALOGICA SINICA Vol. 36, No. 4, 2016, Page 510-518
