Pham Thi Dung

Mineralogical characteristics of arsenopyrite and pyrite in Bo Va and Nam Quang gold-sulfide deposits (Northeast Vietnam)

Crystal morphology and chemical composition of arsenopyrite and pyrite in the Nam Quang and Bo Va deposits of the Song Hien basin (Northeast Vietnam) are studied in detail. Arsenopyrite crystals often form elongated crystals. Their chemical composition are relatively poor in As, but rich in S with S/As ratios often > 1.1, impurity elements such as Ni, Co, Sb, and sometimes containing gold (up to 0.02 wt.%). Pyrite is characterized by the stoichiometric composition, but contains relatively high arsenic and sometimes contain gold. The correlation between the concentration of As and Au in pyrite has been recorded. The morphology and chemical composition of arsenopyrite and pyrite of Bo Va and Nam Quang deposits can be correlated to those in the Au-sulfide deposits in black shale in Kazastan and southestern China. References Trần Trọng Hoa (chủ bien), 1996: Xây dựng mo hinh điều tra, sử dụng hợp lý, bảo vệ moi trường trong qua trinh khai thac tai nguyen khoang sản quý hiếm tỉnh Cao Bằng. Lưu trữ Viện Địa chất, Ha Nội. Trần Trọng Hoa, Polyakov G.V., Trần Tuấn Anh, Borisenko A.S., Izokh A.E., Balyakin P.A., Ngo Thị Phượng, Phạm Thị Dung, 2011: Hoạt động magma va sinh khoang nội mảng miền Bắc Việt Nam. Nxb. Khoa học Tự nhien va Cong nghệ, 368tr. Trần Trọng Hoa, Nevolko P., Ngo Thị Phượng, Trần Tuấn Anh, Phạm Thị Dung, Bui Ấn Nien, Nguyễn Xuân Huyen, Nguyễn Thuy Dương, Vũ Hoang Ly, Trần Văn Hiếu, 2013: Cac tụ khoang vang-sulfide trong cac thanh tạo lục nguyen - carbonat rift Song Hiến, ÐBVN. Tuyển tập Bao cao KHCN toan quốc năm 2013. ISBN: 978-604-59-0693-4; tr.131-140. Nong Thế Tang (chủ bien), 1996: Bao cao Khảo sat va tim kiếm đanh gia vang gốc Nam Quang, Bảo Lạc, Cao Bằng. Lưu trữ Trung tâm Thong tin lưu trữ Địa chất, Ha Nội. Chen M.H., Mao J.W., Bierlein F.P., Norman T., Uttley P.J., 2011: Structural features and metallogenesis of the Carlin-type Lannigou gold deposit, Guizhou Province, China. OreGeol. Rev.43 (1), 217-234. Fleet, M.E., Mumin, A.H., 1997: Gold-bearing pyrite and arsenopyrite from Carlin Trend gold deposits and laboratory synthesis: American Mineralogist, v. 82, p.182-193. Kovalev K.R., Kalinin Yu.A., Naumov E.A., Kolesnikova M.K., Korolyuk V.N., 2011: Gold-bearing arsenopyrite in eastern Kazakhstan gold-sulfide deposits. Russian Geology and Geophysics 52, 178-192. Kovalev K.R., Kalinin Yu.A., Polynov V.I., Kydyrbekov E.L., Borisenko A.S., Naumov E.A., Netesov M.I., Klimenko A.G., and Kolesnikova M.K., 2012: ISSN 1075-7015, Geology of Ore Deposits, vol. 54, No.4, 254-275. Peters S.G., HuangJ.Z., Li Z.P., JingC.G., 2007: Sedimentary rock-hosted Au deposits of the Dian-Qian-Guiarea, Guizhou, Yunnan Provinces, and Guangxi District, China. Ore Geol. Rev.31,170-204. Volkova A. V. , Genkina A. D. , and Academician of the RAS Goncharovb V. I., 2006. New data on invisible gold in disseminated sulfide ores of the Natalka deposit. Vol. 409A, No 6, pp. 879-883. Zhong H.R., Chao S.W., Wu B.X., Zhi T.G., Hofstra A.H., 2002: Geology and geochemistry of Carlin- type gold deposits in China Mineralium Deposita 37:378-39. Zhou T.H., Goldfarb R.J., Phillips G.N., 2002: Tectonics and metallogeny of gold deposits in China. Mineralium Deposita 37, 249-282.