ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 26    No. 6    June 2016

Petrogenesis of skarn in Shizhuyuan W-polymetallic deposit, southern Hunan, China:Constraints from petrology, mineralogy and geochemistry
Yong-sheng CHENG1,2,3
(1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,
Ministry of Education, Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry,
Chinese Academy of Sciences, Guiyang 550002, China
)
Abstract: Skarn is the main altered rock type and is of great importance to mineralization and ore-prospecting in the Shizhuyuan area of Hunan province, China. Its features of petrography, mineralogy and geochemistry were studied systematically. The results show that the skarn mainly consists of garnet skarn, secondary wollastonite-garnet skarn, tremolite-clinozoisite skarn, and few wolframine garnet skarn, idocrase-garnet skarn and wollastonite skarn with granoblastic texture, granular sheet crystalloblastic texture, and massive structure, disseminated structure, mesh-vein structure, comb structure, and banded structure. And, it is mainly composed of garnet, fluorite, chlorite, hornblende, epidote, tremolite, plagioclase, biotite, muscovite, plagioclase, quartz, idocrase, and calcite and so on. The chemical components mainly include SiO2, Al2O3, Fe2O3, MgO and CaO, and the trace elements and REEs consist of Li, Be, V, Co, Zn, Ga, Rb, Sr, Y, Ce, Nd, Pb and Bi, etc. And, the obvious fractionation exists between LREE and HREE, and it shows typical features of Nanling ore-forming granite for W-Sn polymetallic deposit. Skarn is derived from the sedimentary rock, such as limestone, mudstone, argillaceous rock, and few pelitic strips. It is affected by both Shetianqiao formation strata and Qianlishan granite during the diagenesis, indicating a strong reduction environment. The occurrence of skarn, whose mutation site is favorable to the mineralization enrichment, is closely related to the mineralization and prospecting.
Key words: skarn; petrogenesis; geochemistry; Shizhuyuan W-polymetallic deposit; southern Hunan
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)