Jurassic magmatism related Pb-Zn-W-Mo polymetallic mineralization in the central Nanling Range, South China: Geochronologic, geochemical, and isotopic evidence from the Huangshaping deposit

摘要

Graphical abstractDisplay OmittedHighlights?Magmatism at Huangshaping took place during the time interval of 162–148Ma.?Granites at Huangshaping were formed by partial melting of ancient crust.?Ore fluids were mainly crustal-derived, with minor input from the mantle.?Sulfur, lead and other associated metals were tapped from deep crustal sources.AbstractThe Nanling Range in South China is characterized by extensive Mesozoic magmatism and coeval nonferrous and rare metal mineralization. Huangshaping is a world-class Pb-Zn-W-Mo polymetallic skarn deposit in the central Nanling Range. Magmatic rocks occurring in this ore district include quartz porphyry, granite porphyry, granophyre, dacite porphyry, and aplite, with only the first three granitoids genetically associated with polymetallic mineralization. Most of the orebodies are constrained within the contact zones as skarn and veins between these granitic stocks and the carbonate wall rocks.Since the age of the quartz porphyry is still controversial, and studies of the dacite porphyry and aplite are absent, we focus on these magmatic rocks first. LA-ICP-MS zircon U-Pb dating suggests that the crystallization ages of the quartz porphyry, dacite porphyry, and aplite are 154.3±1.9Ma, 158.1±0.8Ma, and 148.4±3.4Ma, respectively. Combined with previously published age data, we infer the evolutionary sequence of magmatic rocks should be dacite porphyry→quartz porphyry→granite porphyry (granophyre)→aplite. The quartz porphyry, dacite porphyry, and aplite yield high contents of high field strength elements (Zr+Nb+Ce+Y=255–440ppm), high ratios of 10,000×Ga/Al (2.6–3.2), and prominent depletions in Ba, Sr, Eu, P, and Ti, indicating their crustal affinities to A-type granites. They have negative εNd(t) values (?9.4 to ?7.0) and high initial Pb isotopic ratios (206Pb/204Pbi=18.307–18.644,207Pb/204Pbi=15.689–15.742,208Pb/204Pbi=38.589–38.986), suggesting that they were probably derived by partial melting of ancient granulitic crustal materials.The sulfide minerals exhibit a wide range of δ34SV-CDTvalues from ?22.6 to 24.2‰, with206Pb/204Pb of 17.66