Origin of the fluorine-rich highly differentiated granites from the Qianlishan composite plutons (South China) and implications for polymetallic mineralization

Generation of Late Mesozoic Qianlishan A 2 -type granite in Nanling Range, South China: Implications for Shizhuyuan W–Sn mineralization and tectonic evolution

“…6a-b). These data are generally consistent with previous zircon U-Pb ages by LA-ICPMS (155-160 Ma, Chen et al, 2014;Shu et al, 2011), but slightly older than those determined by SIMS (152-155 Ma, Li et al, 2004b;Guo et al, 2015). Zircon grains from four P-2 granites give weighted mean…”

“…ratios N 0.1 (Supplemental Table 2S). These inherited zircon grains were also reported by Chen et al (2014), indicating likely crustal assimilation. Zircon grains from the P-3 granite porphyry resemble those of the P-1 granites in shape and color, and also have relatively low Th and U concentrations of 135-552 ppm and 856-4257 ppm with Th/U ratios of 0.15-0.18 (Supplemental Table 2S).…”

“…From the early to late stage, it consists predominantly of three phases, Phase-1 (P-1) is a porphyritic biotite granite ( Fig. 2a) (named "main-phase granite" in Chen et al, 2014 and "P-1 and P-2 granite" in Guo et al, 2015), Phase-2 (P-2) is an equigranular biotite granite (Fig. 2b) (named "highly-differentiated granite" in Chen et al, 2014 and "P-3 granite" in Guo et al, 2015), and Phase-3 (P-3) is a granite porphyry (Fig.…”

“…Quartz occurs as either euhedral crystals in feldspar or anhedral crystals between feldspars, indicating its early or late crystallization, respectively. Plagioclase grains are euhedral, mainly albite (Ab = 96-99.5%, Chen et al, 2014) with typical polysynthetic twin, but some of them are slightly sericitized. Topaz is quite common and has varied sizes from several to hundreds of micrometers in length (Fig.…”

“…The emplacement time of the Qianlishan granitic intrusion has been extensively investigated (e.g., Chen et al, 2014;Guo et al, 2015;Li et al, 2004b;Liu et al, 1997;Wang et al, 1987) (Supplemental Table 6S). The bulk-rock Rb-Sr isochron and mica/K-feldspar (K/Ar)-Ar dates are unreliable in placing temporal constraints on the granites as they are apparently cooling ages and easily affected by thermal disturbance, resetting or chemical alteration, and thus are not considered further here.…”