Petrogenesis and Physicochemical Conditions of Fertile Porphyry in Non‐arc Porphyry Mineralization: A Case from Habo Porphyry Cu‐Mo Deposits, SW China

The Habo deposit is a typical porphyry Cu‐Mo deposit in the Ailaoshan–Red River metallogenic belt. Ore minerals in the Habo deposit typically occur as veins in the monzonite porphyry. Zircon U‐Pb dating suggests that the monzonite porphyry formed at 35.07 ± 0.38 Ma. The monzonite porphyry is charact...

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Published inActa geologica Sinica (Beijing) Vol. 97; no. 2; pp. 469 - 485
Main Authors ZHANG, Aiping, ZHENG, Yuanchuan, SHEN, Yang, Qi, Qunjia, WANG, Zixuan, WU, Changda, WANG, Lu
Format Journal Article
LanguageEnglish
Published Richmond Wiley Subscription Services, Inc 01.04.2023
School of Earth Sciences,Yunnan University,Kunming 650500,China
Yunnan Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,Kunming 650500,China%School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China%State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China%School of Earth Sciences,Yunnan University,Kunming 650500,China
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Summary:The Habo deposit is a typical porphyry Cu‐Mo deposit in the Ailaoshan–Red River metallogenic belt. Ore minerals in the Habo deposit typically occur as veins in the monzonite porphyry. Zircon U‐Pb dating suggests that the monzonite porphyry formed at 35.07 ± 0.38 Ma. The monzonite porphyry is characterized by high SiO2, Al2O3, K2O and Na2O contents, with A/CNK ratios ranging from 0.97 to 1.02. All samples exhibit fractionated REE patterns, characterized by high (La/Yb)N ratios (9.4–13.6, average of 11.2). They show adakite‐like geochemical features, high Sr concentrations (627–751 ppm, average of 700 ppm), low Y concentrations (15.13–16.86 ppm, average of 15.81 ppm) and high Sr/Y values (39.5–47.4, average of 44.3). These samples have high initial 87Sr/86Sr ratios (0.7074–0.7076) and negative εNd(t) values (–5.1 to −3.7), whereas the zircon εHf(t) values range from −2.2 to +0.4, suggesting that the monzonite porphyry was derived from the partial melting of a thickened juvenile lower crust. The oxygen fugacity, calculated on the basis of the chemical composition of the amphiboles, shows ΔNNO values ranging from +1.65 to +2.16 (average of 1.94) and lg(fO2) ranging from −12.72 to −11.99 (average of −12.25), indicating that the monzonite porphyry has high oxygen fugacity. Zircons have high Ce4+/Ce3+ ratios (29.29–164.24, average of 84.92), with high ΔFMQ values ranging from +0.50 to +1.51 (average of 0.87) and high lg(fO2) values ranging from −14.72 to −12.85 (average of −14.07), which also indicates that the oxygen fugacity of the magma was high. The dissolved water content of the Habo monzonite porphyry is 9.5–11.5 wt%, according to the geochemical characteristics, zircon‐saturation thermometry (692–794°C) and the mineral phases (amphibole, no plagioclase) in the deep magma chamber. Combined with previous studies, we propose that the high oxygen fugacity and high water content of magma played key roles in controlling the formation of the Habo and other Cu‐Mo‐Au deposits in the Ailaoshan–Red River metallogenic belt.
Bibliography:ZHANG Aiping, female, born in 1988 in Dali, Yunnan Province; doctor; graduated from China University of Geosciences, Beijing. She is currently interested in the study of mineralogy and petrogeochemistry. E‐mail
About the corresponding author
zhengyuanchuan@gmail.com
About the first author
zap@ynu.edu.cn
ZHENG Yuanchuan, male, born in 1982; doctor; graduated from Nanjing University. He is currently interested in the study of mineralogy, petrography and economic geology. E‐mail
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ISSN:1000-9515
1755-6724
DOI:10.1111/1755-6724.15024