Ar–Ar Ages of Hydrothermal Muscovite and Igneous Biotite at the Guposhan–Huashan District, Northeast Guangxi, South China: Implications for Mesozoic W–Sn Mineralization

Abstract

The Guposhan-Huashan district is an important W-Sn-Sb-Zn-(Cu) metallogenic area in South China. It is located in the middle-west segment of the Nanling Range. Granitoids in the Guposhan-Huashan district possess certain properties of A-type or I-type granites. The W-Sn-Sb-Zn mineralization in the district is closely associated with magma emplacement. Two igneous biotite and seven hydrothermal muscovite samples from skarn, veins and greisenization ores were analyzed by Ar-Ar methods. Two igneous biotite samples from fine-grained quartz monzodiorite and fine-grained biotite granite show plateau ages of 168.7 ± 1.9 Ma and 165.0 ± 1.1 Ma, respectively. Seven hydrothermal muscovite samples from ores yield plateau ages as two groups: 165 Ma to 160 Ma and 104 Ma to 100 Ma. These data suggest that the emplacement of fine-grained granitoids in this district is coeval with the main phase magma emplacement, different from previous studies. The W-Sn-Sb-Zn mineralization took place in two stages, i.e. the Middle-Late Jurassic and early Cretaceous. W-Sn mineralization in the Guposhan-Huashan district is closely related to the magmatism, which was strongly influenced by underplating of asthenospheric mantle along trans-lithospheric deep faults and related fractures.

Cassiterite U-Pb dating and micro-XRF analysis constraint on the formation of Xinlu Sn-Zn deposit, South China

“…The Guposhan-Huashan Sn-W district is one of the most important districts in the western of the Nanling Sn-W belt (Figure 1C). The Sn-W deposits in this district (e.g., Xinlu Sn-Zn deposit, Shuiyanba Sn deposit, Keda Sn deposit, Huashan Sn deposit, and Shanhu W-Sn deposit) are located at the contact zone of the Guposhan-Huashan granite pluton and its vicinity (Figures 1C, 2A;Feng et al, 2019;Gu et al, 2007a, b;Kang et al, 2012;Li et al, 2016;Xiao et al, 2011;Zhang et al, 2020;Zhao et al, 2010). Considerable uncertainty and controversy remains regarding the exact timing of W-Sn mineralization.…”

“…The study area mainly consists of semipelagic flysch sedimentary rocks and subsequently underwent the Early Paleozoic intraplate orogeny. Scattered Mo-W, Pb-Zn, and Au mineralization associated with this orogeny are represented by the Baishiding, Zhanggongling, and Longshui deposits in the eastern of the district (Figure 2A; Li et al, 2016). From Early Devonian to Jurassic, carbonate platforms with sporadic clastic rocks formed in this area under a shore-shallow sea-slope setting (Shu, 2012).…”

“…For example, some studies revealed that no direct genetic link between Sn-W mineralization in the Xinlu deposit and the Guposhan pluton based on whole-rock K-Ar ages and fluid inclusion Rb-Sr ages of the ores (Dong, 1991;Zhu et al, 2006;Gu et al, 2007a). Many researchers have demonstrated that W-Sn mineralization was related to the Guposhan pluton based on zircon U-Pb, molybdenite Re-Os, and muscovite/biotite Ar-Ar dating results in the Xinlu deposit (Kang et al, 2012;Li et al, 2016;Feng et al, 2019). Besides, molybdenite, with Re-Os ages representing the ore-forming ages, is not a major mineral in the Xinlu deposit, and most other tested minerals could not be directly dated for ore-forming ages (Feng et al, 2019).…”

Geochronology and Genesis of the Xitian W-Sn Polymetallic Deposit in Eastern Hunan Province, South China: Evidence from Zircon U-Pb and Muscovite Ar-Ar Dating, Petrochemistry, and Wolframite Sr-Nd-Pb Isotopes

“…The Nanling region is famous for its large-scale and multi-stage magmatism and abundant W, Sn and other rare-metal resources and reserves [2,3,[15][16][17][18][19][20][21][22]. Previous studies have revealed the presence of [2]), showing the distribution of granitic plutons, basalts, and related W-Sn deposits and their geochronological data compiled from [17][18][19]21,29,[31][32][33][34][35][36][37]. TB: Tarim block; CAB: Cathaysian Block; NCB: North China Block; SCB: South China Block; YZB: Yangtze Block.…”

“…These precise data provide detailed chronological constraints on the emplacement age of the Xitian pluton and for the time interval between W-Sn mineralization of the Xitian deposit. The majority of these chronological data show that the Xitian pluton could be subdivided into the Late Triassic (Indosinian) granites (230-220 Ma) and the Late Jurassic (Yanshanian) granites (160-140 Ma), and the time interval for W-Sn [2]), showing the distribution of granitic plutons, basalts, and related W-Sn deposits and their geochronological data compiled from [17][18][19]21,29,[31][32][33][34][35][36][37]. TB: Tarim block; CAB: Cathaysian Block; NCB: North China Block; SCB: South China Block; YZB: Yangtze Block.…”