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[Display omitted] • The mineralization at Tashan is related to the granite porphyry, and both of them formed at ca. 138 Ma. • The granite porphyry is an A-type granite mainly produced from partial melting of crust with minor contribution of mantle materials. • Both the granite porphyry and the mineralization formed in an extensional setting induced by slab roll-back. The medium-sized Tashan Sn deposit, mainly hosted in the Tashan granite porphyry, is located in eastern Guangdong, Southeast China. Zircon U–Pb dating of the granite porphyry yielded a concordant age of 138.0 ± 1.1 Ma, which is consistent with the cassiterite U–Pb age of 138.0 ± 2.3 Ma from the Sn ores, indicating a temporal link between the emplacement of granitic pluton and Sn mineralization. The contents of Fe3+, Fe2+, and Mg2+ in biotite, low calculated zircon Ce4+/Ce3+ of 4.4–71.6, low Eu/Eu* ratios of 0.06–0.35, and low whole-rock Fe 2 O 3 /FeO of 0.04–0.13 of the granite porphyry reveals its low oxygen fugacity, which may have facilitated the Sn enrichment during magma evolution and played a key role in the Sn mineralization. Low K/Rb (150–175, aver. = 160), Nb/Ta (7.3–8.2, aver. = 7.8), and Zr/Hf (23.2–25.1, aver. = 23.9) values were observed for the granite porphyry, indicating its high fractionation and probable interaction with an aqueous fluid phase to some extent. The reduced and highly fractionated features and high F and Sn contents of the granite porphyry thus indicate it is a typical Sn-fertile granite. The granite porphyry is weakly peraluminous and belongs to high-K calc-alkaline type. The rocks are characterized by high SiO 2 , K 2 O + Na 2 O, F, and Zr + Nb + Ce + Y (360–410 ppm) contents; and 10000 Ga/Al (2.31–3.06) ratios and low CaO, MgO, TiO 2 , and P 2 O 5 contents; Rb, Cs, Th, and U enrichment; and Ba, Sr, Zr, Ti, and P depletion, exhibiting an A-type affinity. Moreover, the rocks display whole rock initial 87Sr/86Sr values of 0.70927–0.71218, εNd(t) of − 6.5 to − 6.3, and zircon εHf(t) values from − 5.7 to − 1.5 with Mesoproterozoic T DM2 ages for both Nd and Hf isotopes, indicating their formation by partial melting of a crustal source of Mesoproterozoic overall residence ages with minor input of mantle materials. By integrating new and published data on tectonic evolution, we suggest that the granite porphyry and associated Sn mineralization in the Tashan deposit that was formed in a back-arc extensional environment started before ∼ 141 Ma, related to the rollback of the paleo-Pacific Plate. [ABSTRACT FROM AUTHOR]

• Two pulses of magmatic-hydrothermal fluid are documented in Taoxihu deposit. • The first pulse of fluid is H 2 O-CO 2 -NaCl system and the second one is H 2 O–NaCl. • Fluid immiscibility is responsible for the precipitation of Sn during the first pulse. • The oxidizing process due to the influx of meteoric water accounts for the precipitation of Sn during the second pulse. The Taoxihu deposit is a newly discovered Sn-polymetallic deposit in eastern Guangdong, SE China. The mineralization is related to an Early Cretaceous, highly fractionated I-type granite porphyry. The ore-forming process is divided into six stages, i.e., garnet (stage I), quartz–fluorite–biotite (stage II), quartz–biotite–cassiterite–sulfides (stage III, main mineralization), quartz vein with minor sulfides and cassiterite (stage IV), quartz–K-feldspar–biotite–cassiterite–sulfides (stage V), and quartz–K-feldspar–chlorite–sulfides (stage VI). Fluid inclusion study shows that the hydrothermal fluids from stage II (salinity = 5.9 to 13.2 wt%, and T h = 302 to 382 °C) to stage IV (salinity = 0.2 to 5.9 wt%, and T h = 275 to 315 °C) are of H 2 O–CO 2 –(CH 4)–salt composition and show a trend of systematically decreasing temperature and salinity from early to late stages. In contrast, the fluids in stage V (salinity = 6.5 to 13.9 wt% and T h = 223 to 343 °C) and stage VI (salinity = 6.0 to 11.8 wt%, and T h = 140 to 300 °C) are of the H 2 O–salt compositional system, and demonstrate also a trend of decreasing temperature and salinity with time, representing a distinct hydrothermal event. H–O isotope data indicate that these two different fluid systems are all initially of magmatic origin. In view of the almost identical cassiterite U–Pb ages of stage III (139.7 ± 1.1 Ma) and stage V (139.8 ± 1.6), the two hydrothermal events are interpreted to represent two pulses of magmatic fluid releasing from the same magma chamber. The first pulse is characterized by an initially single-phase CO 2 -bearing magmatic fluid that was subsequently subject to unmixing or phase separation in relation to hydraulic fracturing and decompression, which lead to the main phase mineralization, whereas the second pulse is the release of residual, CO 2 -free magmatic fluid, which mixed with meteoric water and resulted in the second phase of mineralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • We firstly reported the ore ages of the newly discovered Li-rich pegmatite in the NQT. • The newly discovered pegmatites have similar ages to the pegmatite in the MYK. • The pegmatites in the NQT may be formed in a continental collision setting. Lithium–(beryllium) are important strategic metals in modern industries. The Markam–Yajiang–Karakoram (MYK) giant Li ore belt (>14 Mt Li 2 O) is located in the central Qinghai–Tibetan Plateau, and is a world-class Li deposit belt. The reported pegmatite deposits in the belt are mainly found in the Tianshuihai–Songpan–Garzê Terrane (TSGT) and are generally considered to be related to Late Triassic S-type granites and flysch sedimentary rocks. Recently, abundant pegmatite veins have also been discovered in an adjacent terrane (i.e., the North Qaidam Terrane) to the north of the MYK belt, but it is unclear whether these newly discovered pegmatites are genetic related to the MYK belt. Here, we report high-precision columbite–tantalite (i.e., coltan) U–Pb ages and muscovite–lepidolite 40Ar/39Ar ages for the Li–(Be) rare-element pegmatites from the North Qaidam Terrane (NQT) in the Chakabeishan area of the Zongwulong orogenic belt. Coltan grains from three spodumene-bearing pegmatite samples yielded weighted-mean 207Pb-corrected U–Pb ages of 214.9 ± 1.7, 217.0 ± 2.3, and 215.0 ± 1.5 Ma. Muscovite 40Ar/39Ar dating of two spodumene-bearing pegmatite samples and one barren pegmatite sample yielded plateau ages of 213.00 ± 0.97, 211.67 ± 0.35, and 211.78 ± 0.29 Ma, respectively. A lepidolite 40Ar/39Ar age for a lepidolite-bearing pegmatite is 216.62 ± 0.88 Ma. The subtle age differences obtained by the different methods are within reasonable error estimates or may be due to different closure temperatures. The ore-forming ages of the Chakabeishan Li–(Be) rare-element pegmatites are similar to those of Li–(Be) pegmatite deposits in the MYK belt. This and data from previous studies suggest that the Chakabeishan Li–(Be) rare-element pegmatites were also formed in a post-collisional setting after the closure of the Paleo-Tethys (Anyemaqen) Ocean. This study has important implications for understanding the origins of the MYK Li ore belt, indicating that the formation of these Li deposits was not solely associated with the Late Triassic S-type granites and flysch sedimentary rocks. Our results may also have implications for exploration, which extends the potential area of Li deposits from the Tianshuihai–Songpan–Garzê Terrane to the North Qaidam Terrane. [ABSTRACT FROM AUTHOR]

The Bailongshan pegmatite deposit is a newly discovered super-large Li–Rb–(Be–Ta–Nb) rare-metal deposit in the West Kunlun orogenic belt, northwest China. Fifty-two rare-metal orebodies (50–1230 m long by 1.5–157 m wide) have been discovered by detailed field surveying, making up a metallogenic field that is larger than 8250 × 400 m. The deposit is estimated to have ore reserves of more than 5.06 million tonnes (t) Li 2 O, 160,020 t BeO, 316,200 t Rb 2 O, 40,060 t Nb 2 O 5 , and 10,750 t Ta 2 O 5. Pegmatite dikes are zoned around a granodiorite batholith, ranging from barren through orebodies rich in Be, Nb, Ta, Rb, and Li with increasing distance from the batholith, similar to the classical model of a zoned Li–Ce–Ta (LCT)-type pegmatite. LA–ICP–MS analyses of coltan and zircon yield 206Pb/238U ages of 208.1 Ma and 212.3 Ma, respectively, representing the emplacement ages of the pegmatites and granodiorite. These data indicate a temporal link between the emplacement of the granodiorite batholith and rare-metal mineralization in the pegmatites, and that the Bailongshan rare-metal pegmatites are temporospatially related to the granodiorite batholith. The Bailongshan pegmatites and other rare-metal pegmatite deposits in the West Kunlun orogenic belt likely make up a >600-km-long Li metallogenic belt, and further exploration for rare-metal pegmatites should be focused on the area adjacent to Late Triassic granitoid plutons in the belt. This belt likely extends to the East Kunlun and West Sichuan rare-metal belts, forming the >2000-km-long, Late Triassic West Kunlun–Songpan–Garzê rare-metal metallogenic belt. • The Bailongshan deposit is a newly discovered superlarge Li-Rb-(Be-Nb-Ta) pegmatite deposit. • The Bailongshan Li-rich pegmatites (ca. 208 Ma) is closely related to the granodiorite batholith. • Further exploration of Li-rich pegmatite should be around the Late Triassic granitoids. • We highlight a huge "West Kunlun–Songpan-Ganzê rare-metal pegmatite metallogenic belt" occurs. [ABSTRACT FROM AUTHOR]