Journal of Asian Earth Sciences最新文献

{"title":"Eocene SSZ-type ophiolite from Banggi Island, Sabah (Northern Borneo), Malaysia: Zircon U-Pb ages, geochemical characteristics and tectonic implications","authors":"Rezal Rahmat ,&nbsp;Sun-Lin Chung ,&nbsp;Azman Abd Ghani ,&nbsp;Hao-Yang Lee ,&nbsp;Yoshiyuki Iizuka ,&nbsp;Chih-Tung Chen ,&nbsp;Long Xiang Quek","doi":"10.1016/j.jseaes.2025.106919","DOIUrl":"10.1016/j.jseaes.2025.106919","url":null,"abstract":"<div><div>Ophiolites in Sabah are dispersed in a band-shaped lineament stretching from Darvel Bay in the southeast to Banggi Island in the northmost part of Sabah. This study reports the first set of zircons U-Pb ages and whole-rock geochemical data of the Banggi Island Ophiolite (BIO), conventionally regarded as part of the regional Triassic-Eocene “Chert-Spilite Formations” that had been named as the Sabah Ophiolite, and interpreted as remnants of oceanic crust from the proto-South China Sea. LA-ICPMS analyses of zircons separated from five gabbro and two diorite samples gave a short span of ²⁰⁶Pb/²³⁸U ages of ∼ 55–50 Ma (Early Eocene), with high and positive ε_Hf(t) values from + 16.6 to + 10.2 indicating their magma source from a relatively depleted or juvenile mantle. The crustal sequence of Banggi Island Ophiolite, including basalt, gabbro, and diorite, is characterized by depletion in the light rare earth elements and various degrees of enrichment in the large ion lithophile elements, coupled with depletion in Nb and Ta. Their overall geochemical signatures are comparable to the SSZ (supra-subduction zone)-type ophiolites reported from two nearby islands in Palawan and Mindoro, western Philippines. Integrating our new data with regional geologic information, we argue that the Banggi Island Ophiolite represents an SSZ-type ophiolite that formed in the forearc regime at the initial stage of southward subduction of the proto-South China Sea plate. The subduction initiation started from the Early Eocene in Sabah, leading to upper-plate spreading and associated magmatism that gave rise to the crustal rocks of the ophiolite. It may have caused a regional stratigraphic unconformity and later propagated eastward to Palawan and Mindoro, eventually resulting in the ophiolites there and a volcanic arc exposed now as the Cagayan Ridge.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106919"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of meteoric water–rock interaction on the quality of the Middle Jurassic reservoirs along the Hongciliang tectonic belt, Yabulai Basin, NW China","authors":"Shuangqi Feng ,&nbsp;Hancheng Ji ,&nbsp;Liang Chen ,&nbsp;Xuegui Jiang ,&nbsp;Pengfei Xiang ,&nbsp;Yanqing Shi ,&nbsp;Chunfu Liao ,&nbsp;Ying Liu ,&nbsp;Ling Li","doi":"10.1016/j.jseaes.2025.106936","DOIUrl":"10.1016/j.jseaes.2025.106936","url":null,"abstract":"<div><div>In recent years, the penetration of meteoric water through unconformities and porous sandstones, and its subsequent dissolution effects within deep-seated reservoirs, has attracted widespread attention. Assessing whether a diagenetic system is open or closed is crucial for evaluating how dissolution influences reservoir quality. However, for structural uplifts with large-scale, deep-seated faults, how dissolution from meteoric water leaching varies spatially from the structural high to the downdip slope, and the resulting reservoir characteristics, remain poorly understood. To address this, we conducted an integrated analysis of diagenetic mineral assemblages and the associated paragenetic sequence in the Middle Jurassic reservoir of the Hongciliang tectonic belt, Yabulai Basin. Methods included thin-section petrography, scanning electron microscopy (SEM), isotopic testing, X-ray diffraction (XRD), reservoir porosity–permeability measurements, and computerized tomography (CT) scanning. Results demonstrate that the medium- to fine-grained arkoses in the Hongciliang tectonic belt were deposited under similar sedimentary environments. Nevertheless, differential dissolution, coupled with mass transfer and re-precipitation of dissolved materials, results in substantial differences between the structural high and downdip slope. These differences are manifested in the development of dissolution pores, as well as in the types and abundances of authigenic minerals within dissolution pores. Specifically, on the structural high, where well-developed faults define an open geochemical system, extensive dissolution is observed with only limited precipitation of byproducts (e.g., quartz and feldspar overgrowth). Notably, the dissolution of intergranular calcite cements is more prevalent than that of feldspar grains. Reservoir spaces are dominated by interconnected, poorly-cemented intergranular enlarged pores and intragranular dissolution pores. In contrast, on the downdip slope, where the geochemical system is relatively closed, moderate dissolution of both feldspar and calcite cements occurred concurrently with substantial precipitation of byproducts. There, pore systems consist mainly of inter-crystalline pores and poorly connected dissolution pores, with most dissolution pores being occluded by kaolinite, quartz overgrowth and other dissolution-related byproducts. This study indicates that under progressively closed geochemical conditions, the dissolution capacity of meteoric water infiltrating downward through faults and porous sandstones is markedly weakened. Concurrently, the re-precipitation of dissolved cations within the system is enhanced. These coupled diagenetic processes ultimately control the distribution of high-quality reservoirs in uplifted structural belts.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106936"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Archean–early Proterozoic mafic intrusions in the Aravalli Craton (NW India): Implications for the reconstruction of the Kenorland and Columbia supercontinents","authors":"Beiyu Zhou ,&nbsp;Bin Huang ,&nbsp;Manoj K. Pandit ,&nbsp;Wei Wang","doi":"10.1016/j.jseaes.2025.106937","DOIUrl":"10.1016/j.jseaes.2025.106937","url":null,"abstract":"<div><div>Geochronological and geochemical data from mafic intrusions in the Aravalli Craton provide critical insights into the paleogeographic reconstruction of NW India within the Kenorland and Columbia supercontinents. The late Archean Udaipur mafic dykes (2572 ± 12 Ma) display elevated Zr/Nb (12.0–19.2), La/Nb (1.67–3.11) and Ba/Nb (9.62–225) and low Ti/Zr (97.3–100) ratios, indicating derivation from a spinel lherzolite mantle source metasomatized by subduction-related fluids. On the other hand, the Paleoproterozoic Khetri mafic dykes (1848 ± 9 Ma) show comparable Zr/Nb, La/Nb, and Ba/Nb but distinctly higher Th/Nb (1.23–1.32) and Th/Zr (0.11–0.13) ratios, suggesting their derivation from a garnet-spinel lherzolite mantle source metasomatized by both arc-related fluids and melts derived from subducted sediments. The subduction-related geochemical signatures of the ca. 2.57 Ga Udaipur mafic intrusions indicate prolonged arc-related magmatic process characterized by mantle underplating played a vital role in the stabilization of the Aravalli Craton during the late Archean. In contrast, the transitional geochemical characteristics of the ca. 1.85 Ga Khetri mafic rocks mark a tectonic transition from subduction-related to extensional regimes during the Columbia supercontinent assembly. Temporal and geochemical correlations between these mafic magmatic events and coeval ones in the South Indian, Western Australian, and North China cratons support the models suggesting a close spatial proximity of these cratonic blocks during both the late Archean Kenorland (ca. 2.7–2.5 Ga) and the Paleoproterozoic Columbia supercontinent amalgamation processes (ca. 2.0–1.8 Ga).</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106937"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid evolution in the Naxi Fe polymetallic deposit, Eastern Kunlun, China: Insights from in-situ trace element and sulfur isotope compositions of pyrite and pyrrhotite","authors":"Rongqiang Guo ,&nbsp;Shijiong Han ,&nbsp;Chenggang Cao ,&nbsp;Kaizhang Shi ,&nbsp;Yurui Yuan ,&nbsp;Mingyu Tang ,&nbsp;Jinxin Yuan ,&nbsp;Yongkun Fang ,&nbsp;Yushan Jia","doi":"10.1016/j.jseaes.2025.106932","DOIUrl":"10.1016/j.jseaes.2025.106932","url":null,"abstract":"<div><div>The genesis of the Nalinguolehexi (Naxi) skarn Fe polymetallic deposit, Eastern Kunlun, China, remains poorly constrained. This study presents in-situ LA-ICP-MS trace element and sulfur isotope analyses of pyrite and pyrrhotite to decipher its fluid evolution. Four sulfide generations (Py1, Py2, Po, Py3) were identified. Early pyrite (Py1, Py2) is enriched in Co and Ni (Co/Ni &gt; 1), indicating a hydrothermal origin, whereas late-stage Py3 shows pronounced enrichment in As, Pb, Bi, and Sb. Sulfur isotopes (δ³⁴S = −5.9 ‰ to 8.2 ‰) display a decreasing trend from early (avg. 6.6 ‰) to late generations (avg. −5.3 ‰). Elevated early δ³⁴S values suggest magmatic sulfur mixed with crustal or limestone-derived sulfur. Porous textures in Py3, trace element signatures, and principal component analysis collectively indicate a late-stage fluid boiling event. This boiling increased oxygen fugacity and pH, triggering base metal precipitation and inducing kinetic sulfur isotope fractionation responsible for the negative δ³⁴S values. The Naxi deposit is classified as a typical skarn-type system formed by contact metasomatism between magmatic-hydrothermal fluids and the Dagangou Formation limestone. Fluid cooling and boiling were the pivotal mechanisms controlling metal precipitation and isotopic variation. This study identifies geochemical proxies for boiling in skarn systems, offering critical insights for exploring concealed deposits in the Qimantage belt and similar intracontinental settings.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106932"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrocarbon generation and evolution of shale and mudstone: Insights from the Triassic Chang 7 Member in the Ordos Basin, NW China","authors":"Ruihui Zheng ,&nbsp;Zhihuan Zhang ,&nbsp;Yuan Bao ,&nbsp;Zhipeng Li ,&nbsp;Wenhao Li ,&nbsp;Jiao Xue","doi":"10.1016/j.jseaes.2025.106929","DOIUrl":"10.1016/j.jseaes.2025.106929","url":null,"abstract":"<div><div>Shale and mudstone are critical source rocks in continental basins, however, systematic studies on the differences in hydrocarbon generation and evolution processes between these two lithologies remain limited. This paper investigates the shale and mudstone of the seventh member of the Triassic Yanchang Formation (Chang 7 Member) in the Ordos Basin. The Chang 7 Member shale demonstrates a relatively high hydrocarbon generation threshold, rapid conversion rates, and a short generation cycle. Whereas mudstone is characterized by a low generation threshold, slower conversion rates, and a longer generation cycle. The maturity values (<em>R</em>_o) required for the oil generation threshold (conversion ≥ 20 %) are 0.68 % for shale and 0.58 % for mudstone. The onset, peak, and termination maturity values for oil generation are 0.63 %, 0.97 %, and 1.61 %, respectively, for shale, compared to 0.43 %, 1.05 %, and 1.68 % for mudstone. The optimal maturity ranges for oil generation are 0.68 %–1.21 % for shale and 0.58 %–1.33 % for mudstone. Spatial variations in burial depth and thermal evolution history across the Ordos Basin result in a progressive northward increase in the depth intervals corresponding to peak oil generation for both lithologies within the Chang 7 Member. Notably, the Chang 7 Member shale and mudstone in the Jiyuan area exhibit higher oil generation conversion efficiency, indicating significant potential for shale oil exploration. These findings provide valuable insights for advancing shale oil resource exploration and determining optimal temperature conditions for <em>in-situ</em> shale pyrolysis in the Ordos Basin.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106929"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early Paleozoic magmatism and Au mineralization in the central Truong Son Belt: Insights from geochronology and lead isotope at the Me Xi gold deposit, Vietnam","authors":"Truong Xuan Le ,&nbsp;Khin Zaw ,&nbsp;Hai Thanh Tran ,&nbsp;Sebastien Meffre ,&nbsp;Pham Trung Hieu ,&nbsp;Nguyen Dinh Luyen ,&nbsp;Luong Quang Khang ,&nbsp;Dinh Trong Tuong","doi":"10.1016/j.jseaes.2025.106938","DOIUrl":"10.1016/j.jseaes.2025.106938","url":null,"abstract":"<div><div>The Me Xi Au deposit lies within the central Truong Son Belt, which is the largest geological structure in the Indochina Block. This region was primarily shaped by the Ordovician-Silurian (O-S) Caledonian and Permian-Early Triassic (P-T₁) Indosinian orogenies. In this study, LA-ICP-MS apatite and zircon ages, along with lead isotopic composition obtained from galena and pyrite at the Me Xi Au deposit using Aqua Regia digestion and LA-ICP-MS techniques have been analysed. The results confirmed that: (1) the porphyritic dolerite yields an apatite U-Pb age of 448 ± 33 Ma. However, considering the stratigraphic constraints, this likely represents an emplacement age of ∼430–415 Ma within the analytical uncertainty range. Combined with the geochemical signatures (e.g., Zr/TiO₂ and Ti/V ratios) of an extensional setting and the historical geology, this indicates a post-collision magmatism related to the Caledonian Orogeny between the Truong Son Belt and Kon Tum Massif; (2) the early Au-mineralization event (Stage 2) has predominantly upper-crustal lead sources with Paleozoic model ages. This is possibly linked to the ∼430–415 Ma post-collision dolerite of the Caledonian Orogeny; (3) the late Au-mineralization event (Stage 3) has mixed magmatic-upper crustal lead sources and Mesozoic model ages, possibly marks a metallogenic event during the post-collision phase of the Indosinian Orogeny; (4) host rocks at Me Xi comprising siltstone and sandstone are constrained by a maximum depositional age of ∼580 Ma (i.e., youngest detrital zircon) and the minimum age of ∼430–415 Ma (i.e., ages of dolerite crosscutting metasedimentary rocks). These results highlight the significance of Ordovician-Silurian magmatism in the regional tectonic framework and metallogenic evolution of the central Truong Son Belt.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106938"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-proxy provenance records from the Yanyuan Basin reveal the Cenozoic tectonic evolution along the southeastern Tibetan Plateau","authors":"Yuquan Jiang ,&nbsp;Linlin Li ,&nbsp;Xiangjiang Yu ,&nbsp;Zhongtai He ,&nbsp;Dewen Li ,&nbsp;Yingying Li","doi":"10.1016/j.jseaes.2025.106928","DOIUrl":"10.1016/j.jseaes.2025.106928","url":null,"abstract":"<div><div>The timing of surface uplift and the evolution of paleodrainage systems in the southeastern Tibetan Plateau remain highly debated. The Yanyuan Basin on the southeastern margin of the Tibetan Plateau preserves key sedimentary archives of the Cenozoic tectonic evolution. This study integrates detrital zircon U-Pb geochronology with single-grain geochemical analyses of tourmaline, garnet, and rutile to reconstruct provenance changes from the Eocene Hongyazi Formation to the Pliocene–Early Pleistocene Xigeda Formation. The Eocene strata along the western margin were mainly derived from weakly metamorphosed Triassic clastic rocks of the southern Yidun Terrane, together with Neoproterozoic toTriassic intermediate–acidic intrusions exposed along the basin margins, whereas the southern margin was dominated by detritus from the Emeishan basalts. In contrast, the Xigeda Formation records a markedly different sedimentary source-to-sink system: both the western and northern margins were primarily supplied by proximal sources exhumed from the Jinhe–Qinghe and Muli thrust faults, particularly Neoproterozoic intermediate–acidic plutons. This transition reflects a fundamental reorganization of drainage networks and catchment boundaries, associated with the shift from early-stage plateau uplift and regionally integrated paleodrainage to late-stage tectonic compartmentalization under thrusting and strike-slip deformation. The combined zircon age spectra and detrital heavy mineral geochemistry provide robust constraints on sediment provenance, paleogeographic reconfiguration, and the mechanisms of tectonic transformation along the southeastern margin of the Tibetan Plateau during the Cenozoic.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106928"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microtremor-based site characterization for Gujarat broadband seismological network established in an intraplate setting","authors":"Harsh Limbachiya ,&nbsp;Sumer Chopra ,&nbsp;Tarun Solanki","doi":"10.1016/j.jseaes.2025.106934","DOIUrl":"10.1016/j.jseaes.2025.106934","url":null,"abstract":"<div><div>A network of broadband seismic stations has been deployed across the Gujarat region in western India, covering diverse geological settings. Microtremor data obtained at these stations are used to characterize the sites through horizontal to vertical spectral ratio (HVSR) analysis. The HVSR curves are modeled to derive 1D shear-wave velocity (<em>V_S</em>) profile beneath each site. The fundamental frequency (<em>f₀</em>) across the Gujarat varies between 0.2 and 17.7 Hz with values of 0.2–0.5 Hz and 0.9–1.2 Hz observed for sites located on Quaternary and Rann sediments, respectively. Most sites underlain by Tertiary and Cretaceous formations exhibit flat HVSR curves, while Deccan Trap sites show similarly flat responses up to 10 Hz. The <em>V_S30</em>, a key parameter for site characterization, varies from 228 to 743 m/s across Gujarat. At sites underlain by Quaternary sediments, the average <em>V_S30</em> is 288 ± 34 m/s. For Tertiary, Jurassic, Cretaceous and Proterozoic formations, the average <em>V_S30</em> values are 413 ± 85 m/s, 478 ± 76 m/s, 435 ± 56 m/s and 680 ± 28 m/s, respectively. In Deccan Traps, an average <em>V_S30</em> of 585 ± 64 m/s is observed. The <em>V_S30</em> values obtained from the HVSR modelling show good agreement with those obtained from active seismic methods such as multi-channel analysis of surface waves (MASW). This study presents the first region-wide site characterization of Gujarat using microtremor data. It demonstrates the efficacy of HVSR-based modeling in capturing geology-controlled variations in site response across a tectonically active and lithologically complex region. The results provide essential inputs for seismic hazard assessment, engineering design, and future microzonation studies in western India.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106934"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of non-colinear fault systems from extension to transtension: Northern Dongying Sag, Bohai Bay Basin, East China","authors":"Meng Zhang ,&nbsp;Kuihua Zhang ,&nbsp;Shuang Song ,&nbsp;Yanjun Cheng ,&nbsp;Zhiping Wu","doi":"10.1016/j.jseaes.2025.106925","DOIUrl":"10.1016/j.jseaes.2025.106925","url":null,"abstract":"<div><div>Many rift basins present non-colinear fault systems; however, different mechanisms can contribute to such fault patterns. Understanding the evolution of non-colinear faults is crucial for evaluating the paleo-stress and kinematics of rift basins. Using well-constrained 3D seismic data, we demonstrate the evolution of a basin-bounding fault and non-colinear minor faults over 40 Myr in the northern Dongying Sag, Bohai Bay Basin, East China. During the Paleocene–Middle Eocene (66–42.7 Ma), an E–W-striking basin-bounding fault and many minor faults with the same strike developed in response to regional extension. A small number of NW–SE-striking minor faults also developed, attributed to the reactivation of pre-Cenozoic faults. In the subsequent ∼ 2 Myr, the through-going basin-bounding fault surface bifurcated upwards into two overlapping master faults, accompanied with the development of splay faults. Depocentres started to migrate towards hanging walls of the splay faults. At ∼ 40.9 Ma, splay faults with a left-stepping configuration along the NE–SW direction developed and linked with the main fault plane, leading to a transition of sedimentary distribution from E–W to NE–SW. Meanwhile, E–W-, NE–SW- and NW–SE-striking minor faults synchronously developed, and some of the NE–SW-striking minor faults present a left-stepping, <em>en-echelon</em> arrangement. The non-colinear faults are likely to correspond to subsidiary structures in a dextral transtensional setting, associated with the right-lateral movement of a continental-scale fault, Tan-Lu Fault Zone. The Bohai Bay Basin may be suitable for a kinematic model of extension followed by dextral transtension during the Paleogene.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106925"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Triassic ore-forming adakitic porphyries from post-collisional lithospheric extension in the eastern Kunlun Orogen, northern Tibet","authors":"Jinyang Zhang ,&nbsp;Zhongyuan Ma ,&nbsp;Yong Zhang ,&nbsp;Jianxun Yuan ,&nbsp;Jiaxing Chai ,&nbsp;Lanxin Zhang ,&nbsp;Changqian Ma ,&nbsp;Jianwei Li ,&nbsp;Yuanming Pan","doi":"10.1016/j.jseaes.2025.106922","DOIUrl":"10.1016/j.jseaes.2025.106922","url":null,"abstract":"<div><div>Post-collisional porphyry Cu systems are commonly associated with adakitic intrusions and lithospheric extension. In this study, Wulanwuzhu’er porphyritic diorites and Yazigou dolerites have been investigated to support Late Triassic adakitic rocks for porphyry Cu systems of the eastern Kunlun Orogen formed in post-collisional lithospheric extension. The porphyritic diorites emplaced as dykes at 211–214 Ma are ‌spatiotemporally and genetically related to the epithermal Ag-Pb-Zn mineralization. The diorites contain high Al₂O₃ hornblende (up to 13.74 wt%) and belong to metaluminous and high-K calc-alkaline series with moderately high Sr/Y values and enriched Nd isotopes. They were most likely derived from a moderately oxidized metasomatic lithosphere mantle under a post-collisional setting, with adakitic signatures caused by hornblende crystallization at the lower crust. The dolerite dykes (222 ± 1.3 Ma) are metaluminous and calc-alkaline with high Mg#, Ni (up to 103 ppm), and <em>ε</em>_Nd(<em>t</em>) values (up to 6.1). They were originated from a depleted mantle in the spinel stability field with small melting degrees, supporting a significant upwelling of the asthenosphere to induce the post-collisional lithospheric extension. Systematic compilation of regional geochemical data in the orogen suggests that Late Triassic adakitic intrusions in the eastern section have higher MgO and Ni contents and oxygen fugacities than the counterparts in the western section, probably indicating a slab tearing model. Vigorous lower crustal magmatic processes in a thickened continental crust, the post-collisional slab tearing, and oxidized sources of metasomatic mantle or subducted slab for the eastern Kunlun Orogen are favorable for porphyry Cu mineralization.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106922"},"PeriodicalIF":2.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}