The East Kunlun Orogen on the northern margin of the Tethyan orogenic system records a history of Gondwana dispersal and Laurasian accretion. Uncertainties remain regarding the detailed histories of northern branches of the Paleo-Tethys Ocean in East Kunlun Orogen (Buqingshan Ocean). Based on a synthesis of sedimentary, structural, lithological, geochemical, and geochronological data from the East Kunlun Orogen and adjacent regions, this paper discusses the spreading and northward consumption of the Paleo-Tethys Ocean during Late Paleozoic–Early Mesozoic times. The main evolutionary stages are: (1) during Carboniferous to Middle Permian, the Paleo-Tethys Ocean (Buqingshan Ocean) was in an ocean spreading stage, as suggested by the occurrence of Carboniferous MORB-, and OIB-type oceanic units and Carboniferous to Middle Permian Passive continental margin deposits; (2) the Buqingshan Ocean subducted northward beneath the East Kunlun Terrane, leading to the development of a large continental magmatic arc (Burhan Budai arc) and forearc basin between ~270–240 Ma; (3) during the late Middle Triassic to early Late Triassic (ca. 240–230 Ma), the Qiangtang terrane collided with the East Kunlun–Qaidam terranes, leading to the final closure of the Buqingshan Ocean and occurrences of minor collision-type magmatism and potentially inception of the Bayan Har foreland basin; (4) finally, the East Kunlun Orogen evolved into a post-collisional stage and produced major magmatic flare-ups and polymetallic mineral deposits between Late Triassic to Early Jurassic (ca. 230–200 Ma), which is possibly related to asthenospheric mantle upwelling induced by delamination of thickened continental lithosphere and partial melting of the lower crust. In this paper, we propose that the Wilson cycle-like processes controlled the Late Paleozoic–Early Triassic tectonic evolution of East Kunlun, which provides significant implications for the evolution of the Paleo-Tethys Ocean.

Numerous Indosinian granitoids occur in the East Kunlun Orogen (EKO). The Indosinian was a key transitional period associated with the evolution of the Paleo-Tethys Ocean. Here, we study the relationship between the petrogenesis of the granitoids and the regional tectonic setting based on a comprehensive analysis of the petrology, geochronology, and geochemistry of typical granitoids in the eastern part of the EKO. The Indosinian granitoid compositions are dominated by quartz diorites, granodiorites, monzogranites, porphyritic monzogranites, and syenogranites. Early Indosinian granitoids are large, granitic batholiths, while the middle and late Indosinian granitoids are smaller in size. From the early Indosinian to late Indosinian, the granitoids show a transition from a medium-K calc-alkaline to high-K calc-alkaline composition. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) and depleted in high-field-strength elements (HFSEs), especially for the Helegangxilikete and the Kekeealong plutons. The late Indosinian granitoids have relatively low Y and Yb contents, high Sr contents, and high La/Yb and Sr/Y ratios, which suggests adakitic affinity. The zircon saturation temperatures of the early Indosinian syenogranite and the Keri syenogranite are above 800 °C. The zircon saturation temperatures of other Indosinian granites (average 749 °C) are lower than those of the biotite and amphibole partial melting experiment. In the early Indosinian (255–240 Ma), numerous granitoids were the products of the partial melting of the juvenile lower crust by mafic magma underplating. This underplating is geodynamically related to the continuous subduction of a branch of Paleo-Tethys Ocean, with slab break-off, rapid upwelling, and mantle decompression. In the middle Indosinian (240–230 Ma), the compression that accompanied the continent–continent collision was not conducive to fluid activity, and hence, the formation of magma could be attributed to dehydration partial melting of muscovite, biotite, or amphibole. In the late Indosinian (230–200 Ma), the delamination of thickened crust would provide heat and channels for fluid migration, leading to a flare-up of the magmas. The composition and petrogenesis of the Indosinian granitoids in the eastern EKO are the result of processes associated with the subduction, collisional, and post-collisional stages, during the evolution of the Paleo-Tethys Ocean.

Large volumes of Early Mesozoic intermediate to basic igneous rocks related to the evolution of the Paleo-Tethys Ocean are exposed in the East Kunlun Orogenic Belt (EKOB). The petrography, geochemistry, and results of zircon U-Pb dating of Defusheng intermediate to basic rocks from the eastern segment of the EKOB are presented in this report. Zircon U–Pb dating of the intermediate to basic rocks yields ages of 239–245 Ma (Middle Triassic). Defusheng intermediate to basic rocks have low TiO₂ contents (0.80–1.47 wt.%) and widely varying MgO (3.14–6.08 wt.%), and are enriched in large ion lithophile elements and light rare earth elements, having a geochemical composition similar to that of island arc basalts. The variation diagrams of major elements indicate that the Defusheng intermediate to basic rocks underwent fractional clinopyroxene and olivine crystallization. Depletion of the high-field-strength elements Nb, Ta, and Ti may have been caused by the mantle wedge having been infiltrated by fluids derived from the subducted slab. The Defusheng intermediate to basic rocks represent magmatic records of the Early Mesozoic oceanic crust subduction in Eastern Kunlun. This indicates that the final closure of the Paleo-Tethyan Ocean and the beginning of collisional orogeny occurred after the Middle Triassic.

Amidst the intensification of strategic mineral exploration, the discovery of concealed and deep-seated deposits within covered areas and the peripheries of existing mines has become a critical challenge and a central focus of contemporary research. “Dongchuan-type” (DCT) copper deposits represent a key mineralization style within the SW Yangtze Block. However, significant exploration breakthroughs have stagnated over the past three decades. Consequently, advanced exploration prediction research is urgently required to guide deep-resource evaluation. Using the Shizishan copper deposit in the Yimen area as a representative case, this study applies the theory of “metallogenic geological body prediction” to construct a tripartite model encompassing “metallogenic geological bodies, metallogenic structures and structural planes, and metallogenic characteristic markers”. The Shizishan deposit is classified as a sedimentary-reformed type, characterized by multi-episodic mineralization involving initial sedimentary processes, non-magmatic hydrothermal activity, and subsequent structural-magmatic hydrothermal overprinting. Key metallogenic geological bodies include ore-bearing stratigraphic associations, basin-margin faults, NE-trending fold–fault systems, and deep-seated concealed intrusions. Metallogenic structural planes comprise primary ore-controlling surfaces, secondary fold-related structures, and potential deep-seated magmatic intrusive interfaces. Alteration patterns display a distinct vertical zonation: shallower levels show medium-to-low temperature hydrothermal processes (silicification, carbonatization, sericitization, and chloritization), whereas deeper portions reveal high-temperature magmatic–hydrothermal indicators, specifically skarnization and intense silicification. This study proposes that the integration of “stratigraphy + structures + concealed intrusions” should serve as the primary criterion for target screening in deep exploration. By integrating geophysical and geochemical datasets into this model, three promising exploration targets were delineated within the Yimen area. These findings provide a refined theoretical framework for large-scale prospecting of DCT.