Geochemical Characteristics and Zonation of Primary Halos of Pulang Porphyry Copper Deposit, Northwestern Yunnan Province, Southwestern China

详细信息    查看全文

• 作者：Chen Yongqing ; Huang Jingning ; Liang Zhen
• 关键词：Pulang porphyry copper deposit ; zonation of primary halo ; assessment of Cu potential at depth ; Tethys-Himalaya ore-forming domain ; southwestern China
• 刊名：Journal of China University of Geosciences
• 出版年：2008
• 出版时间：August 2008
• 年：2008
• 卷：19
• 期：4
• 页码：371-377

文摘

The Pulang porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large copper deposit. Compared with the composition of granodiorite in China, the porphyry rocks in this area are enriched in W, Mo, Cu, Au, As, Sb, F, V, and Na₂O (K₁≥1.2). Compared with the composition of fresh porphyry rocks in this district, the mineralized rocks are enriched in Cu, Au, Ag, Mo, Pb, Zn, W, As, Sb, and K₂O (K₂≥1.2). Some elements show clear anomalies, such as Zn, Ag, Cu, Au, W, and Mo, and can be regarded as pathfinders for prospecting new ore bodies in depth. It has been inferred from factor analysis that the Pulang porphyry copper deposit may have undergone the multiple stages of alteration and mineralization: (a) Cu-Au mineralization; (b) W-Mo mineralization; and (c) silicification and potassic metasomatism in the whole ore-forming process. A detailed zonation sequence of indicator elements is obtained using the variability index of indicator elements as follows: Zn→Ag→Cu→Au→W→Mo. According to this zonation, an index such as (Ag×Zn)_D/(Mo×W)_D can be constructed and regarded as a significant criterion for predicting the Cu potential at a particular depth.