Geochronology, Petrology, and Genesis of Two Granitic Plutons of the Xianghualing Ore Field in South Hunan Province: Constraints from Zircon U–Pb Dating, Geochemistry, and Lu–Hf Isotopic Compositions

Lizhi Yang,Yushuang Gong,Weidong Liu,Xiaowen Zhang,Xiangbin Wu,Jingya Cao,Bin Hu

doi:10.3390/min8050213

Abstract

Two small-sized granitic plutons, outcropped in Xianghualing ore field, South Hunan (South China), have a close relationship with the super large-scale Sn–W polymetallic mineralization in this ore field. The Laiziling and Jianfengling plutons are composed of medium- to coarse-grained two-mica and coarse-grained biotite granites, respectively, and have zircon U–Pb ages of 156.4 ± 1.4 Ma and 165.2 ± 1.4 Ma, respectively. Both of the Laiziling and Jianfengling granites are characterized by extremely similar elemental and Lu–Hf isotopic compositions with high contents of SiO2, Al2O3, Na2O, K2O, high A/CNK ratios, negative εHf(t) values (ranging from −3.86 to −1.38 and from −5.44 to −3.71, respectively), and old TDMC ages (ranging from 1.30 to 1.47 Ga and from 1.32 to 1.56 Ga, respectively). These features indicate that they both belong to highly fractionated A-type granites, and were formed in an extensional setting and from the same magma chamber originated from the Paleoproterozoic metamorphic basement of South China with a certain amount of mantle-derived magma involved with temperatures of ca. 730 °C and low oxygen fugacity.

Highlights

South Hunan, located in the central part of the Shi-Hang zone, is well-known for its world-classW–Sn–Pb–Zn polymetallic deposits and reserves (Figure 1a)
Most of the zircons from medium- to coarse-grained two-mica granite of Laiziling pluton are euhedral, with obvious internal oscillatory zoning in CL images (Figure 4a), indicating a magmatic origin of these zircons [35]
Most of the zircons from coarse-grained biotite granite of Jianfengling pluton are featured by euhedral and obvious internal oscillatory zoning in CL images (Figure 4c), indicating a magmatic origin of these zircons [35]

Summary

Introduction

South Hunan, located in the central part of the Shi-Hang zone, is well-known for its world-classW–Sn–Pb–Zn polymetallic deposits and reserves (Figure 1a). As a significant part of the Shi-Hang zone, the W–Sn–Pb–Zn mineralization in this South Hunan possesses an obvious zoning feature from east to west: Shizhuyuan and Yaogangxian W deposits in the eastern part, Furong, Xianghualing and Furong Sn deposits in the middle part, and Huangshaping and Baoshan Pb–Zn. Minerals 2018, 8, 213; doi:10.3390/min8050213 www.mdpi.com/journal/minerals plutons related with these large deposits have been drawn the attention of geologists, and abundant geochronological and geochemical data have been reported recently, such as Qitianling pluton 8, 213 deposit [16]), and Baoshan pluton (158 ± 2 Ma, associated with the Baoshan Cu–Mo–Pb–Zn deposit [6]) These coeval granitic plutons in South Hunan, related to different metallic mineralization, have deposits in theplace western part (Figure 1b). Sn biggest Sn–W–Pb–Zn ore fields in China, and consists of Xianghualing Sn deposit (a super-large Sn deposit), Dongshan (a large deposit) and many small-medium sized deposits (Figure 2)

Results

Discussion

Conclusion