The Western Kunlun-Pamir-Karakorum (WKPK) at the northwestern Tibetan Plateau underwent long-term terrane accretion from the Paleozoic to the Cenozoic. Within this time span, four phases of magmatism occurred in WKPK during the Early Paleozoic, Triassic-Jurassic, Early Cretaceous, and Cenozoic. These voluminous magmatic rocks contain critical information on the evolution of the Tethys Oceans. In this contribution, we provide field observations, petrography, ages, whole-rock elemental and Sr-Nd isotopic compositions, and zircon in situ Lu-Hf isotopes of the Triassic-Jurassic granitoids and pegmatites from the Dahongliutan in Western Kunlun and Turuke area at the Pamir Plateau, in an attempt to constrain their petrogenesis and to decipher a more detailed Paleo-Tethys evolution process. The Dahongliutan pluton is composed of diorites (ca. 210 Ma) and monzogranite (ca. 200 Ma). The diorites have moderate SiO₂ (56.77–62.22 wt. %), variable Mg^# (46–49), and low Cr (34.4–50.6 ppm) and Ni contents (7.0–14.5 ppm). They show LREE-enriched patterns (⁠ $LaN/YbN=4.3–17$⁠), with variable negative Eu anomalies (0.63–0.91) and variable ratios of Nb/La (0.27–0.97). Isotopically, the diorites display enriched whole-rock $εNdt$ (-5.43 to -7.67) and negative to positive zircon $εHft$ values (-6.6 to 0.4). They were most likely generated by melting of a subduction-modified mantle source with subsequent assimilation and fractional crystallization. The Turuke monzogranites (ca. 202–197 Ma) have S-type granite characteristics and are characterized by high SiO₂ (70.36–76.12 wt. %) and A/CNK values (1.19–1.36), variable LREE-enriched patterns (⁠ $LaN/YbN=8.87–14.40$⁠), negative Eu anomaly (0.07–0.56), relatively uniform whole-rock $εNdt$ (-10.49 to -11.22), and variable negative zircon $εHft$ values (-10.7 to -1.3). They were probably generated by muscovite-dehydration melting of dominantly metapelitic sources. The widespread pegmatites (ca. 195 Ma) at the Dahongliutan area record an extensional setting after the collision of Karakorum with the South Kunlun-Tianshuihai terrane. Combining our new data with the previous studies, we propose a divergent double-sided subduction of the Paleo-Tethys Ocean (243–208 Ma) and a gradual closure of the Paleo-Tethys Ocean from east (ca. 200 Ma) to west (ca. 180 Ma) to explain the Triassic-Jurassic tectono-magmatism in the WKPK.

The Beihuaiyang Zone (BHY) is one of the most important Mo–Pb–Zn polymetallic metallogenic belts in China, and the BHY deposits are genetically and geographically associated with Cretaceous magmatic rocks. In this article, we present new zircon U–Pb ages and Hf isotope data, whole-rock major and trace-element analytical results, and Sr–Nd–Pb isotope data for the granite porphyry of the Shapinggou (SPG) Mo deposit and the quartz monzonite porphyry of the Gongdongchong (GDC) Pb–Zn deposit. The high contents of SiO₂, crust-like rare-earth-element and trace element patterns, and the enriched Sr–Nd–Pb–Hf isotopic compositions indicate that both porphyries originated from crustal melting. Inherited Neoproterozoic zircons are common in both porphyries, which implies that their crustal sources were the South China Block rather than the North China Block. Whole-rock ε_Nd(t) values (−10.8 to −9.8 for the GDC deposit, −12.9 to −12.4 for the SPG deposit) and zircon ε_Hf(t) values (−14.3 to −11.1 for the GDC deposit, −18.4 to −13.3 for the SPG deposit) for the ore-bearing rocks are significantly higher than the values found in the widespread and older ore-barren rocks, indicating that the magma sources of the ore-bearing rocks were younger than those of the ore-barren rocks. An integrated study of the Sr–Nd–Pb–Hf isotope contents shows that these younger source rocks are similar to the gneisses found in the South and Central Dabie units, which represent the upper crust of the subducted South China Block. Given the geochemical behaviour of molybdenum, a surface enrichment process would have been an essential prerequisite for the formation of the large Mo deposit. The early Paleozoic Mo–Pb–Zn-enriched black shales, which are widespread in the upper layers of the South China Block, might have been scraped off during Triassic subduction and then transported to deep-crustal levels below the BHY, thus forming an ideal source for the ore-bearing porphyries. An upper-crustal origin for the ore-bearing magmatic rocks is also consistent with the data for most other deposits distributed in the BHY of the Dabie Orogen.

The Late Carboniferous to Early Permian is a critical period of the Chinese Tianshan, witnessing the tectonic transition from subduction to post-collisional extension during the final amalgamation of the Central Asian Orogenic Belt (CAOB). The late Carboniferous Mozbaysay mafic–ultramafic complex in the Qijiaojing–Balikun area, eastern North Tianshan, provides important clues for revealing the nature and timing of this tectonic transition. The Mozbaysay complex comprises mainly hornblende gabbros and lherzolites. LA-ICP-MS U-Pb zircon ages of hornblende gabbro yielded a weighted mean age of 306 ± 1.9 Ma for this complex. These mafic–ultramafic rocks have high contents of MgO (up to 30 wt.%), Cr (up to 2493 ppm), and Ni (up to 1041 ppm), but low contents of SiO₂ (40.34–47.70 wt.%). They are enriched in LREE and show characteristics of enriched mid-ocean ridge basalts (E-MORB). The relatively high Th/Yb and Ba/Nb ratios imply the mantle sources could have been metasomatized by slab–mantle interaction with aqueous fluids from dehydration of the subducted slab. Thus, these mafic–ultramafic rocks were most likely produced by partial melting of the asthenospheric and lithospheric mantle with a slight influence of slab-derived fluids. Therefore, we suggest that the formation of these Late Carboniferous mafic–ultramafic rocks was triggered by the decompression-induced influx of asthenospheric heat and melting through a slab window during post-collisional slab breakoff. Combined with geological data, the petrogenetic links of the Late Carboniferous mafic–ultramafic rocks in eastern North Tianshan to slab breakoff suggest that the tectonic transition from convergence to post-collision most likely initiated in situ at ca. 306 Ma and lasted to ca. 300 Ma.

Recent discoveries of fluorite–barite deposits in the Donghai–Linshu area in northern Jiangsu Province, China, underscore the region’s mineral potential, yet detailed geological investigations remain limited. In this study, we examined monzonite and quartz monzonite from drill cores in the Jiashan mining area using petrography, U–Pb zircon dating, zircon trace element geochemistry, whole-rock geochemistry, and zircon Lu–Hf isotopes. Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) zircon U–Pb analyses were conducted to constrain the crystallization ages of the monzonite (127.06 ± 0.54 Ma and 126.83 ± 0.75 Ma) and quartz monzonite (127.2 ± 0.5 Ma and 128.59 ± 0.62 Ma) to the Early Cretaceous, marking a significant magmatic event. Many of the zircons contain inherited Neoproterozoic cores (718–760 Ma and 800–860 Ma), indicating the assimilation of deep crustal materials of this age. The monzonite is metaluminous, with moderate SiO₂ (61.61–62.41 wt.%), high alkalis (Na₂O + K₂O = 7.48–7.92 wt.%), and A/CNK = 0.72–0.91. The quartz monzonite has higher SiO₂ (66.26–68.18 wt.%) and alkalis (8.32–9.33 wt.%). Both rock types exhibit similar trace and rare earth element patterns: enrichment in large-ion lithophile and light rare earth elements, depletions in Nb, Ta, and Ti, no significant Zr-Hf depletion, and weak negative Eu anomalies (δEu ≈ 0.84–1.00). Their low Zr + Nb + Ce + Y contents, Ga/Al ratios, and TFeO/MgO ratios indicate that they have an I-type granite affinity. The Early Cretaceous zircons have highly negative ε_Hf(t) values (−33.7 to −23.5) and ancient two-stage model ages (2622–3247 Ma), which are consistent with derivation from Archean crust. The inherited Neoproterozoic zircons have younger Paleo–Mesoproterozoic T_DM2 ages. The evidence suggests that both intrusions were mainly generated by partial melting of ancient Archean basement, with minor mantle input. The magma generation was likely triggered by crustal anatexis induced by the underplating of mantle-derived magmas in an extensional tectonic regime, coeval with Early Cretaceous magmatism in the Sulu orogen.