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

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 SiO 2 , Al 2 O 3 , Na 2 O, K 2 O, high A/CNK ratios, negative ε Hf (t) values (ranging from −3.86 to −1.38 and from −5.44 to −3.71, respectively), and old T DMC 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.

Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

“…However, the P 2 O 5 content of the quartz syenite has a negative correlation with SiO 2 and positive correlation with Th and Y (Supplementary Materials Figure S2), indicating the quartz syenite is not an S-type granite. Moreover, the samples display high contents of SiO 2 , total alkali (K 2 O + Na 2 O) and REE, features consistent with A-type granite [81][82][83], and the composition of these samples fall into the field of A-type granite in the discrimination diagrams of granites introduced by Whalen et al [81] ( Figure 11). As a result, the petrography and geochemical characteristics strongly suggest an A-type affinity for the quartz syenite.…”

Geology and Geochronology of the Maozaishan Sn Deposit, Hunan Province: Constraints from Zircon U–Pb and Muscovite Ar–Ar Dating

“…Consequently, these highly fractionated Middle Jurassic granites of the Dayishan pluton with low oxygen fugacity and crust-mantle origin are similar to those Sn-related granites in the Nanling Range (e.g., Jiuyishan, Xitian, Qitianling, and Guposhan) [6,[11][12][13]. These unique properties of these granites result in the formation of the Maozaishan deposit and other large-scale Sn deposits in the Nanling Range, making this region a significant Sn metallogenic domain in China.…”

“…It was highlighted that these factors of the felsic melt, including the fractionated signature, source, and redox condition, play crucial roles in controlling the Sn mineralization [57][58][59][60][61][62][63][64][65]. Firstly, the worldwide cases have proved that highly fractionated granites are favorable for Sn mineralization, since Sn tends to be enriched in the late stage melt [12,13,59]. Secondly, magma, originated from these crustal rocks, including meta-sedimentaryand/or meta-volcanic-rocks, would be in favor of Sn mineralization, however, the mantle sources could also attribute to the Sn mineralization [66].…”

Metal Sources of World-Class Polymetallic W–Sn Skarns in the Nanling Range, South China: Granites versus Sedimentary Rocks?

“…The Sn mineralization of the Xianghualing deposit is hosted by the Laiziling pluton, with albite granite as its major rock type [72]. Based on geochronological studies, the crystallization age of the Laiziling granite is about 155-150 Ma [23,33,39,73,74].…”