Zircon U-Pb geochronological framework of Qitianling granite batholith, middle part of Nanling Range, South China

Abstract

The Qitianling granite batholith (QGB) is located in the southern Hunan Province, middle part of the Nanling Range, South China. Its total exposure area is about 520 km 2 . Based on our 25 single grain zircon U-Pb age data and 7 published data as well as the geological, petrological, and space distribution characteristics, we conclude that QGB is an Early Yanshanian (Jurassic) multi-staged composite pluton. Its formation process can be subdivided into three major stages. The first stage, emplaced at 163-160 Ma with a peak at about 161 Ma, is mainly composed of hornblende-biotite monzonitic granites and locally biotite granites, and distributed in the eastern, northern, and western peripheral parts of the pluton. The second stage, emplaced at 157-153 Ma with a peak at 157-156 Ma, is mainly composed of biotite granites and locally containing hornblende, and distributed in the middle and southeastern parts of the pluton. The third stage, emplaced at 150-146 Ma with a peak at about 149 Ma, is mainly composed of fine-grained (locally porphyritic) biotite granites, and distributed in the middle-southern part of the pluton. Each stage can be further disintegrated into several granite bodies. The first two intrusive stages comprise the major phase of QGB, and the third intrusive stage comprises the additional phase. Many second stage fine-grained granite bosses and dykes intruded into the first stage host granites with clear chilling margin-baking phenomena at their intrusive contacts. They were emplaced in the open fracture space of the earlier stage consolidated rocks. Their isotopic ages are mostly 2-6 Ma younger than their hosts. Conceivably, the time interval from magma emplacement, through cooling, crystallization, solidification, up to fracturing of the earlier stage granites cannot exceed 2-6 Ma. During the Middle-Late Jurassic in the Qitianling area and neighboring Nanling Range, the coeval granitic and basic-intermediate magmatic activities were widely developed. It indicates that the Early Yanshanian period was the culmination time of magmatic activities in this region. The Nanling Range was under a post-orogenic, intracontinental geotectonic environment with an obvious lithospheric extension and thinning. The crust-mantle interaction played an important role in formation of granitic rocks in this region.

Elemental and Sr-Nd-Hf isotopic constraints on the origin of Late Jurassic adakitic granodiorite in central Fujian province, southeast China

“…The origin of the Changchengling (~178 Ma) and Ningyuan (~174 Ma) basaltic rocks in southern Hunan (Jiang et al 2009) and the Dexing adakitic porphyries (~171 Ma) in northeastern Jiangxi (Zhou et al 2012) (Fig. 1a) Zhu et al 2006a, b;Qitianling (QTL), Zhu et al 2009;Jinjiling (JJL) and Xishan (XS), Jiang et al 2009; Huashan (HS), Zhu et al 2006a; Guposhan (GPS), Zhu et al 2006b]; b Simplified geological map of the Tangquan pluton; c Simplified geological map of the Xiadao pluton A-type granites in the Shi-Hang zone (Fig. 1a) (e.g., Jiang et al 2006a;2009).…”

Indium Mineralization in the Xianghualing Sn-Polymetallic Orefield in Southern Hunan, Southern China

“…The outcropping strata in the belt consists of Sinian to Cambrian low-grade metamorphic rocks, Devonian to Lower Triassic limestone intercalated with clastic rocks, and Upper Triassic to Tertiary sandstone and siltstone. The Yangshanian granites intrude extensively in southern Hunan with the largest being the Qitianling intrusion [31][32][33], and they control the formation of a number of large-scale porphyry, skarn, and vein-type W-Sn-Pb-Zn deposits (Figure 1b), e.g., the Shizhuyuan [34], Baoshan [35], Huangshaping [36][37][38], Xianghualing [39], Xintianling [35], Yaoganxiang [30], Baiyunxian, and Furong deposits [35,40].…”

Gravity method for investigating the geological structures associated with W–Sn polymetallic deposits in the Nanling Range, China

“…While these tectonic events were responsible for multi-stage granitic intrusive bodies, the crust-mantle interaction played an important role in the formation of the granitic rocks (Chen, 1989;Zhu et al, 2009). Mao et al (2009) have suggested a comprehensive deposit model related to magma intrusions in South China (Fig.2).…”