Bainiuchang super-large silver-polymetallic ore deposit related to granitic magmatism in Mengzi, Yunnan

Abstract

Bainiuchang silver-polymetallic ore deposit is located in the southeast Yunnan tin-polymetallic metallogenic belt. The probable reserves and inferred resources of the deposit are of 6 470 t Ag and 1.10 Mt Pb and 1.72 Mt Zn and 86 kt Sn. Orebodies of the deposit occur in clastic-carbonate rocks of Tianpeng Formation and Longha Formation of the middle Cambrian System above the Bainiuchang concealed granite of the late Yanshan period. The concealed granite has the characteristics of tin-bearing granites. Abundance of the mineralization elements Sn, Cu, Zn, Pb, Ag and Sb is high in the granitic rocks. Sulphur isotope data of the metal sulphides indicate that most sulphur is derived from the magmas. The ores are similar in rare earth element(REE) patterns to the granitic rocks. The granitic magma activity results in ore-bearing structures. Rocks of the Middle Cambrian System above the concealed intrusion suffer from skarnization, hornfelsing, marbleization, siliconizing and carbonatization. The mineralization elements Sn, Cu, Zn, Pb, Ag and Sb successively appear from the top of the granite to surrounding rocks. These evidences indicate that the granitic magmatism is the principal mineralization factor. The opinion that the south Bainiuchang ore field and the north Awei ore block are tin and copper potential exploration areas was put forward and was verified by drilling tests.

Keywords

Bainiuchang / super-large silver-polymetallic deposit / granite / granitic-porphyry / tin ore

References

[1] LuoJ.-lie.. The minerogenetic characteristics of super-large deposits in Yunnan[J]. Yunnan Geology, 1995, 14(4): 276-80

[2] ChenX.-m., LinZ., XieF.-chang.. Geological and geochemical characteristics of the Bainiuchang super-large silver polymentallic deposit of superimposed mineralization, Yunnan Province[J]. Scientia Geologica Sinica, 1998, 33(1): 115-124

[3] ZhouJ.-p., XuK.-q., HuaR.-m., et al.. Characteristics and genesis of exhalative sedimentary massive sulfides in southeastern Yunnan Province[J]. Acta Mineralogical Sinica, 1998, 18(2): 158-168

[4] DengJ., ChenX.-m., RaoY.-q., et al.. Two kinds of compaction fluid systems of the Nanling area[J]. Geoscience, 2004, 18(1): 1-7

[5] HuaR.-m., ZhuJ.-c., ZhaoY.-y., et al.. Preliminary studying on metallogenetic series of nonferrous metal deposits in Youjiang fold belt[J]. Geological Journal of China Universities, 1997, 3(2): 183-190

[6] ZhuC.-h., ZhangQ., HeY.-liang.. The characteristics of mineralizing elements of the Bainiuchang silver Polymetallic deposit in southeastern Yunnan[J]. Bulletin of Mineralogy, Petrology and Geochemistry, 2005, 24(4): 327-332

[7] LiuJ.-s., GaoZ.-g., DengG.-q., et al.. One potential superlarge Pb-Zn ore occurrence with Himalayan thermal brine genesis—Wuqia Region, Xinjiang, China[J]. Journal of Central South University of Technology, 2002, 9(1): 41-46

[8] YANG Shi-yu. Characteristics of distribution in time and its metallogenic model[J]. Scientia Geologica Sinica, 1990(2): 137–148. (in Chinese)

[9] QinD.-x., TanS.-c., FanZ.-g., et al.. Geotectonic evolution and tin-polymentallic metallogenesis in Gejiu-Dachang area[J]. Acta Minerralogica Sinica, 2004, 24(2): 117-123

[10] GaoZ.-ying.On the Mineralization of Bainiuchang Silver Polymetallic Deposit in Mengzi[M], 1998, Kunming, Yunnan Science and Technology Press

[11] LIU Ji-shun, ZHANG Hong-pei, FANG Wei-xuan et al. Problems pertaining to Bainiuchang silver, polymetallic deposit in Mengzi country, Yunan[J]. Engineering Science, 2005, (Suppl.): 238–244. (in Chinese)

[12] BreiterK., SokolovaM., SokolA.. Geochemical speciabization of the tin-bearing granitoid massifs of NW Bohemia[J]. Mineralium Deposita, 1991, 26(4): 298-306

[13] BayG. E., WebsterI. C. L., BallantyneS. B., et al.. The geochemistry of three Tin-bearing skarns and their related platonic rocks, Atlin, northern British Cdumbia[J]. Economic Geology, 2000, 95(6): 1349-1365

[14] ChenJ., WangH.-nian.Geochemistry[M], 2004, Beijing, Science Press

[15] YuC.-w., TangY.-j., ShiP.-f., et al.Dynamical System of Mineralization in Gejiu tin Polymetallic Deposit[M], 1988, Wuhan, China University of Geosciences Press

[16] GuanR.-sheng.. An approach of mineralization of granite mass in the structure tectonicmagmatic belt in southeast of Yunnan[J]. Journal of Minerology and Ptrology, 1991, 11(1): 92-101

[17] LI Xi-ji, YANG Zhuang, SHI Lin, et al. Tin deposits of China[C]// SONG Shu-he, et al. Mineral Deposits of China. Beijing: Geological Publishing House, 2:105–188. (in Chinese)

[18] EinaudiM. T., BurtD. M.. A special issue devoted to skarn deposits; Instruction—terrninology, classification, and composition of skarn deposits[J]. Bulletin of the Society of Economic Geologists, 1982, 77(4): 745-754

[19] MEINERT L D. Application of skarn deposit zonation models to mineral exploration[J]. Exploration and Mining Geology, 1997(6): 195–208.