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Metallogenic Mechanism and Geodynamic Background of the Chang'an Chong Cu-Mo Deposit in Southern Ailaoshan Tectonic Belt: New Evidence from Garnet U-Pb Dating and In-Situ S Isotope.

Authors :
Sun, Bin
Liu, Yi
Yan, Yongfeng
Ye, Lei
Chen, Gang
Source :
Minerals (2075-163X); Nov2022, Vol. 12 Issue 11, p1389, 16p
Publication Year :
2022

Abstract

The Chang'an Chong Cu-Mo deposit is located in the Chang'an Cu-Mo-Au ore cluster in the southern Ailaoshan tectonic belt in southwestern China. There are six intrusive bodies in the mining area, among which the No.Ⅱ intrusive body is the largest and most closely related to Cu-Mo mineralization of skarn. The No. 1 main orebody is composed of the No. 1 copper orebody and No. 1 molybdenum orebody, which are distributed in parallel with similar shapes. In this paper, the age of skarn is determined by the LA-SF-ICP-MS U-Pb dating of garnet, and it is nearly consistent with the age of alkaline porphyry in this region (41–32 Ma). Compared with the U-Pb age of zircon from the ore-bearing porphyry and the Re-Os age of molybdenite, the U-Pb age of garnet was consistent with them within error, indicating that they were the same mineralization event, which further proves that the porphyry-skarn Cu-Mo-Au mineralization event along the Ailaoshan-Red River fault zone mainly occurred at 38~32 Ma. In-situ S isotope results show that the δ<superscript>34</superscript>S mean values of disseminated pyrite (PyI), pyrite of sulfide veins (PyⅡ) and chalcopyrite (Ccp) in the main mineralization period are 2.35‰, 3.60‰ and 0.55‰, respectively. These δ<superscript>34</superscript>S values are similar to those of magma and slightly enriched in δ<superscript>34</superscript>S, and the δ<superscript>34</superscript>S value of chalcopyrite is mainly concentrated near 0‰, so it can be considered that the S of the ore-forming fluid came from magmatic-hydrothermal fluids. Based on the comprehensive analysis of the regional metallogenic background, deposit chronology and isotope geochemistry, it is concluded that the Chang'an Chong Cu-Mo deposit was formed in an intra-plate post-collision strike-slip environment. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
2075163X
Volume :
12
Issue :
11
Database :
Complementary Index
Journal :
Minerals (2075-163X)
Publication Type :
Academic Journal
Accession number :
160206931
Full Text :
https://doi.org/10.3390/min12111389