Geological, Geochronological, and Geochemical Insights into the Formation of the Giant Pulang Porphyry Cu (–Mo–Au) Deposit in Northwestern Yunnan Province, SW China

Guo-Liang Zhang,Zhong-Jie Yang,Jing-Mou Li,Yu-Jie Hao,Yun-Sheng Ren,Qing-Hong Zeng,Zhen-Ming Sun,Sheng-Bo Chen,Qun Yang,Xin-Hao Sun

doi:10.3390/min9030191

Abstract

The giant Pulang porphyry Cu (–Mo–Au) deposit in Northwestern Yunnan Province, China, is located in the southern part of the Triassic Yidun Arc. The Cu orebodies are mainly hosted in quartz monzonite porphyry (QMP) intruding quartz diorite porphyry (QDP) and cut by granodiorite porphyry (GP). New LA-ICP-MS zircon U–Pb ages indicate that QDP (227 ± 2 Ma), QMP (218 ± 1 Ma, 219 ± 1 Ma), and GP (209 ± 1 Ma) are significantly different in age; however, the molybdenite Re–Os isochron age (218 ± 2 Ma) indicates a close temporal and genetic relationship between Cu mineralization and QMP. Pulang porphyry intrusions are enriched in light rare-earth elements (LREEs) and large ion lithophile elements (LILEs), and depleted in heavy rare-earth elements (HREEs) and high field-strength elements (HFSEs), with moderately negative Eu anomalies. They are high in SiO2, Al2O3, Sr, Na2O/K2O, Mg#, and Sr/Y, but low in Y, and Yb, suggesting a geochemical affinity to high-silica (HSA) adakitic rocks. These features are used to infer that the Pulang HSA porphyry intrusions were derived from the partial melting of a basaltic oceanic-slab. These magmas reacted with peridotite during their ascent through the mantle wedge. This is interpreted to indicate that the Pulang Cu deposit and associated magmatism can be linked to the synchronous westward subduction of the Ganzi–Litang oceanic lithosphere, which has been established as Late Triassic.

Highlights

Two famous porphyry mineralization systems in Western Yunnan Province, Southwestern (SW)China, mainly compose the Yidun Arc metallogenic belt in the north and the Jinshajiang–Red River metallogenic belt in the south (Figure 1A)
Numerous porphyry and skarn Cu deposits have been discovered in the area, and representative deposits include Pulang, Xuejiping, Lannitang, Songnuo, Langdu, and Chundu (Figure 1C)
Cu mineralization ages in the southern Yidun Arc have been constrained to the Late

Summary

Introduction

Two famous porphyry mineralization systems in Western Yunnan Province, Southwestern (SW). Mainly compose the Yidun Arc metallogenic belt in the north and the Jinshajiang–Red River metallogenic belt in the south (Figure 1A). The southern Yidun Arc (Figure 1B), namely, the Zhongdian. Numerous porphyry and skarn Cu deposits have been discovered in the area, and representative deposits include Pulang, Xuejiping, Lannitang, Songnuo, Langdu, and Chundu (Figure 1C). The geological characteristics and geochronological data indicate that these. Cu deposits have a temporal and spatial relationship with widespread Mesozoic intermediate-acid intrusions [1,2,3,4,5,6,7,8,9]. Extensive isotopic geochronology studies have been carried out on these Cu deposits. Cu mineralization ages in the southern Yidun Arc have been constrained to the Late

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Conclusion