Journal of Asian Earth Sciences最新文献

{"title":"The Ediacaran tectonics in the northern margin of Gondwana: constraints from the doleritic dykes in the Sanandaj–Sirjan Zone, Iran","authors":"Fariba Riyahi ,&nbsp;Nahid Shabanian ,&nbsp;Ali Reza Davoudian ,&nbsp;Yunpeng Dong","doi":"10.1016/j.jseaes.2025.106947","DOIUrl":"10.1016/j.jseaes.2025.106947","url":null,"abstract":"<div><div>The Ediacaran period (635–641 Ma) exhibits an important shift in earth history, from the breakup of Rodinia to the formation of Gondwana. The Sanandaj–Sirjan Zone (SaSZ) in Iran, located along the Northern Gondwana margin, records Neoproterozoic-Cambrian events (580–520 Ma). Ediacaran tectonic setting in the zone has been debatably mentioned from an active margin with arc magmatism or a passive rift setting related to continental extension. The North Shahrekord metamorphic complex, in the central SaSZ, is dominated by metamorphosed mafic intrusions. Doleritic dykes intruding this complex are key to reconstructing the tectonic evolution of Gondwana’s northern margin. U-Pb zircon dating from the mafic dykes gives an age of 552 ± 10 Ma, indicating crystallization during the Ediacaran and representing a major extensional event. Geochemical analyses reveal sub-alkaline to alkaline magma compositions, with high TiO₂ (1.15 and 3.45 wt%) and Mg# (51.35 and 66.94) values. Primitive mantle normalized trace element patterns display enrichments in LILE (Ba, Sr, K) and HFSE (Nb, Ta, Ti), indicating Ocean Island Basalt (OIB) or Enriched Mid-Ocean Ridge Basalt sources (E-MORB). The magma likely originated from a mixture of asthenospheric and lithospheric mantle, with minor crustal and slab-related contributions, consistent with a within-plate or continental rifting setting. Thus, at ∼552 Ma, the SaSZ margin was undergoing a lithospheric extension in an intra-continental tectonic setting. Our findings provide new geochronological and geochemical constraints on Ediacaran extensional phases, linking the SaSZ crustal thinning to the failed break-up of the Gondwana margin.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106947"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078802","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":"Dynamic rupture modeling of the Kachchh Mainland Fault (KMF), Bhuj, India: Implications for earthquake risk assessment","authors":"T.C. Sunilkumar ,&nbsp;Danhua Xin ,&nbsp;Zhenguo Zhang ,&nbsp;V.K. Gahalaut ,&nbsp;Zijia Wang ,&nbsp;Zhongqiu He","doi":"10.1016/j.jseaes.2026.106956","DOIUrl":"10.1016/j.jseaes.2026.106956","url":null,"abstract":"<div><div>The seismic hazard associated with the Kachchh Mainland Fault, the prominent fault of the Kachchh failed rift region of western India, remains high, where the 2001 Mw∼7.7 Bhuj earthquake occurred. This area necessitates an in-depth investigation into the fault’s dynamics and associated risks. We employed advanced physics-based (PB) simulations to explore dynamic rupture scenarios, focusing on how rupture influences ground motion patterns and hazard. We adopted a magnitude of Mw 7.7 consistent with the 2001 event, with the fault segment immediately west of the 2001 epicenter, considering its possible dimensions. By varying nucleation points across models, we observed comparable rupture characteristics; however, ground motion simulations produced distinctly different patterns, influenced by directivity, hanging-wall effects, and fault geometry. This highlights the advantages of using PB simulations over traditional Ground Motion Prediction Equations and other models. Simulated intensity levels in models peak at Modified Mercalli Intensity (MMI) IX, with site amplification leading to intensities up to X. We evaluated population exposure to different MMI levels, revealing distinct patterns that correlate with variations in ground motion. These findings underscore the critical need for comprehensive seismic risk assessments that integrate a detailed study of the earthquake source. Although the KMF has not historically been linked to catastrophic earthquakes in recent centuries, our results indicate its potential for significant large events, necessitating enhanced earthquake monitoring and preparedness, and assessment of neighboring fault systems.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106956"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928853","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":"The Earth magnetic field in the Mesoproterozoic – a new assessment of paleomagnetic secular variation from Arctic Siberia, Russia","authors":"Aleksandr Pasenko ,&nbsp;Ivan Lebedev ,&nbsp;Dmitrii Ushakov","doi":"10.1016/j.jseaes.2026.106951","DOIUrl":"10.1016/j.jseaes.2026.106951","url":null,"abstract":"<div><div>The hypothesis that the Earth’s magnetic field can be approximated by a time-averaged geocentric axial dipole (GAD) allows paleomagnetic data to be used in developing paleogeographic reconstructions. For the Precambrian, this hypothesis needs to be tested for different time intervals. On the other hand, information on the evolution of the geomagnetic field during the Precambrian can be used to shed light on the processes of deep geodynamics and the evolution of the Earth’s core. One of the numerical parameters characterizing the state of the geomagnetic field is the amplitude of the paleosecular variations (PSV), estimated from the scatter of the directions of the natural remanent magnetization. We propose a new estimate of PSV amplitude calculated for low latitudes of ∼1.5 Ga over 36 individual sites, which is unique for such determinations in the Precambrian. Our new estimate of S_b = <span><math><mrow><mn>10.2</mn><mfrac><mrow><mn>13.0</mn></mrow><mrow><mn>9.5</mn></mrow></mfrac></mrow></math></span>° is consistent with recent G-models for Precambrian. It indicates that in the Mesoproterozoic, the contribution of symmetric magnetic field components to geomagnetic variations was comparable to the Mesozoic and to the present-day.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106951"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980904","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 Carboniferous tectonic setting of the Kalamaili suture Zone, north Junggar (NW China): Constraints from the volcanic rocks in the geological section of Songkaersu Formation","authors":"Qianru Cai ,&nbsp;Jinduo Wang ,&nbsp;Guanlong Zhang ,&nbsp;Zhengrong Xiong ,&nbsp;Hongzhou Yu ,&nbsp;Jian Zhou ,&nbsp;Zhihua Song","doi":"10.1016/j.jseaes.2026.106950","DOIUrl":"10.1016/j.jseaes.2026.106950","url":null,"abstract":"<div><div>The mid-Early Carboniferous period characterized by widespread magmatism represents a key tectonic transition stage for the Kalamaili suture zone of Northeastern Junggar. Debates persist on the petrogenesis and tectonic setting of these Early Carboniferous igneous rocks, restricting our understanding of the Late Paleozoic tectonic evolution. In this study, we performed integrated geochronological and geochemical analyses on intermediate-basic volcanic rocks of the Songkaersu Formation from the Shuangjingzi North and Xidagou South profiles along the southern Kalamaili suture zone. Zircon U-Pb dating of three samples constrains magmatic activity to 344–332 Ma. The rocks comprise basalt, basaltic andesite, and andesite, exhibiting calc-alkaline affinity. Their geochemical compositions demonstrate variable SiO₂ (46.76–62.87 wt%), MgO (1.49–6.42 wt%), and K₂O (0.23–3.68 wt%), moderate TiO₂ (0.42–1.19 wt%), and elevated Na₂O (2.89–5.85 wt%) and P₂O₅ (0.21–0.59 wt%) contents. Enrichment in large-ion lithophile elements (LILEs: Rb, Ba, K) and light rare earth elements (LREEs), coupled with depletion in high-field-strength elements (HFSEs: Nb, Ta, Ti), suggests arc-related affinity. Radiogenic isotope signatures reveal low initial ⁸⁷Sr/⁸⁶Sr ratios (0.7039–0.7043) and significant variations in ε_Nd (t) (+5.0 – +7.5) and ε_Hf (t) values (+0.05 – +12.62). These features imply derivation from partial melting of previously subducted slab-derived fluids metasomatized depleted mantle lithosphere. The integrated geochemical and isotopic patterns, combined with evidence of mantle material upwelling driven by lithospheric thinning, indicate a post-collisional intraplate tectonic setting. Collectively, these results suggest that the northeastern Junggar Basin transitioned to a post-collisional regime by at least the middle Early-Carboniferous.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106950"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908887","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":"Source and accumulation of helium in the Dongsheng gas Field, Ordos Basin, China: Insights from noble gas isotopes","authors":"Yu Gao ,&nbsp;Shuangjian Li ,&nbsp;Xiaoqi Wu ,&nbsp;Dongya Zhu ,&nbsp;Pengpeng Li ,&nbsp;Linlin Wang ,&nbsp;Guangxiang Liu ,&nbsp;Jiahao Lv ,&nbsp;Jiarun Liu ,&nbsp;Quanyou Liu","doi":"10.1016/j.jseaes.2026.106959","DOIUrl":"10.1016/j.jseaes.2026.106959","url":null,"abstract":"<div><div>Helium, vital for advanced technologies, is generated in the crust via uranium (U) and thorium (Th) decay. The crystalline basement is a proven source of helium. In contrast, the role of sedimentary rocks, while often considered significant, has lacked definitive proof. This study provides the isotopic evidence to deconvolve these two crustal sources and verify the significant role of sediment. Our analysis of the Dongsheng Gas Field, Ordos Basin, China, reveals that air-derived noble gases reflect open-system water–gas equilibration, a process occurring within the reservoir. Whereas crust-derived noble gases likely pre-aggregated and migrated together with hydrocarbons, thereby preserving a clear signature of their original sources. Within this preserved signature, a depletion of ²¹Ne* (where * denotes a crustal origin) is observed. This depletion produces an unusual negative correlation between ²¹Ne*/³⁶Ar and ⁴⁰Ar*/³⁶Ar, in contrast to the expected positive trend. This pattern is interpreted as the mixing of a fluid from coal-bearing strata (⁴⁰Ar*/³⁶Ar = 130 ± 10) with a ²¹Ne*-depleted fluid from the basement (⁴⁰Ar*/³⁶Ar = 2250 ± 150). Modeling suggests that only ∼ 0.26 % of basement-generated ²¹Ne* is retained. We propose a helium accumulation model in which initial preservation was inefficient owing to the absence of a seal, whereas the main accumulation was driven by hydrocarbon charging, which acted as a carrier fluid stripping helium from coal-bearing strata. These results demonstrate that U- and Th-rich sedimentary rocks can serve as a potential helium source in natural gas, which refines exploration strategies for helium in cratonic basins.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106959"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980903","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":"Wolframite and cassiterite geochemistry deciphers W–Sn ore formation: A case study from the Zuoba quartz-vein tungsten deposit, South China","authors":"Kai-Han Zhang ,&nbsp;Jun-Yi Pan ,&nbsp;Pei Ni ,&nbsp;Gen-Wen He ,&nbsp;Lin-Lin Peng ,&nbsp;Ming-Sen Fan ,&nbsp;Yuan-Long Zhang ,&nbsp;Wen-Sheng Li","doi":"10.1016/j.jseaes.2026.106953","DOIUrl":"10.1016/j.jseaes.2026.106953","url":null,"abstract":"<div><div>The Zuoba deposit is a typical quartz-vein type tungsten deposit in the Nanling metallogenic belt. Here, we present LA-ICP-MS U–Pb dating and trace-element analyses of wolframite and cassiterite to decipher the ore forming process of this deposit. Wolframite yields a lower intercept age of 156.7 ± 0.9  Ma, and cassiterite shows a weighted mean ²⁰⁶Pb/²³⁸U age of 155.2 ± 1.5  Ma. Wolframite shows enrichments in Nb, Ta, and Sc, along with a distinctly low Zr/Hf ratio and left-inclined REE patterns marked by negative Eu anomalies. This geochemical signature points to ore-forming fluids derived predominantly from highly evolved granites and precipitated under reducing conditions. Coupled Mg–Fe variations suggest alteration-driven Fe input, highlighting the contribution of wall-rock interaction to wolframite precipitation. Cassiterite exhibits CL-bright and CL-dark sector zoning, with continuous growth bands across both, indicating that these zones developed synchronously during the same crystallization stage. Variations in W and U between the sectors are primarily attributed to crystal growth kinetics rather than to changes in fluid redox conditions. Cassiterite Zr/Hf ratios exhibit a strong sensitivity to the degree of evolution and chemical composition of the parental magmas, with W-dominated systems typically characterized by lower values than those from Sn-dominated deposits. Because Nb, Ta, and Nb/Ta show pronounced sector-zoning differences, only CL-bright sector data should be used to interpret the ore genesis. The Nb and Ta variations of Zuoba cassiterite reflect temperature fluctuations during cassiterite deposition and suggest a possible contribution from meteoric-water mixing during cassiterite mineralization.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106953"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928777","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":"Integrated seismic hazard assessment around Qom City, North-Central Iran, based on earthquake focal mechanisms, fault-slip data, and deterministic analysis","authors":"Mohadese Ajami,&nbsp;Abdollah Sohrabi-Bidar,&nbsp;Reza Nozaem","doi":"10.1016/j.jseaes.2025.106945","DOIUrl":"10.1016/j.jseaes.2025.106945","url":null,"abstract":"<div><div>Iran is located in the central part of the Alpine-Himalayan orogenic belt, experiencing significant and destructive earthquakes throughout its history. Obviously, major and strategically important cities hold great significance in the event of an earthquake, considering their political and social importance. Among the important cities of Iran, Qom is a populous and significant city in the northern part of the central Iranian zone. This paper presents a seismotectonic assessment by examining and analyzing seismic and fault-slip data to determine the average attitude of the principal stress tensors within a 150 km radius of Qom city. Next, these findings were integrated with the results of deterministic seismic analysis and utilized in the Fault Motion Potential (FMP) method to evaluate the risk level of major surrounding faults in Qom. Modern and paleostress assessments determined that the trend of the maximum principal stress axis is about N30E, approximately aligning with the current convergence of the Arabian-Eurasian plates in central Iran. Consequently, under such a dominant stress regime, the movement capacity of a fault is directly linked to the relation between fault geometry and the main stress axes. Furthermore, fault length and its distance to the site are key parameters for assessing the potential seismic hazard based on the evaluation of a Deterministic risk event. Deterministic risk study identified Qom, Alborz, and Haji-Abad faults as the most seismic risk influencing factors in the region. Fault motion potential (FMP) values were computed for these faults by using modern and paleostress data with respect to each fault pole geometry. The outcome of our study indicated that the Qom and Alborz faults have high reactivation potential for earthquake generation, with FMP values of 0.6 and 0.7, respectively. In contrast, the Haji-Abad fault, with an FMP value of 0.3, represents a moderate seismic risk level. Earthquakes that occur along this fault can reach magnitudes up to 7.2 Mw. The results of this research can be used in the urban development programming of Qom, and adjacent areas.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106945"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928851","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":"Precise subsurface structural delineation of gold fields and crustal architecture from remote sensing and satellite geophysical data in Asir and Jiddah terranes, Makkah area, Saudi Arabian Shield","authors":"Ahmed M. Eldosouky ,&nbsp;Reda A.Y. El-Qassas ,&nbsp;Mohamed A. Abd El‑Wahed ,&nbsp;Abdullah Othman ,&nbsp;Luan Thanh Pham ,&nbsp;Mohamed Attia","doi":"10.1016/j.jseaes.2026.106957","DOIUrl":"10.1016/j.jseaes.2026.106957","url":null,"abstract":"<div><div>The crustal structure and gold fields of the Asir and Jiddah terranes in the Makkah region of the Arabian Shield are examined using a comprehensive methodology that integrates Landsat-8 imagery with gravity and magnetic data. An Enhanced Horizontal Gradient Amplitude (EHGA) filter helps identify the structures controlling the gold mineralization. The region is primarily characterized by the Ad Damm and Fatima fault zones, which are mylonitic dextral shear zones exhibiting flexural slip folding and a thrust duplex system. Various structural orientations distinguish the Asir and Jiddah terranes, including NW, NE, N-S to NNE, E-W, and WNW trends. Deeper structural features generally follow the same trends, with some shifts toward N-S and NE-to-ENE directions. The study covers gold fields such as As Suq, Ar Rjum, Ad Duwayhi, and Shaab Al Taare, where mineralization is influenced by E-W and N-S trending structures. The crust thickness (Moho interface) in the Makkah area varies from 25 to 46 km. The region has undergone three major deformation phases, with the youngest event being the most intense, producing folds, faults, and fractures. These results offer new insights into the tectonic architecture and structural framework of the Arabian Shield in this area and enhance the understanding of the geodynamic processes and crustal formation shaping Asir and Jiddah terranes.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106957"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928850","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":"The stepwise closure of the Tethyan Seaway in the Burdigalian (Early Miocene): A multiproxy sequence stratigraphic approach (Qom Basin, Iran)","authors":"Masoud Sharifi-Yazdi ,&nbsp;Kateřina Schöpfer ,&nbsp;Susanne Gier ,&nbsp;Iuliana Vasiliev ,&nbsp;Michael Wagreich","doi":"10.1016/j.jseaes.2026.106971","DOIUrl":"10.1016/j.jseaes.2026.106971","url":null,"abstract":"<div><div>This study analyses the closure history of the Tethyan Seaway, connecting the Tethys and the Indian Ocean, during the Early Miocene as recorded in Central Iran. Understanding the timing and mechanisms of this closure is essential for reconstructing regional paleogeography, oceanic circulation, and the broader implications for global climate during the Neogene. The upper part of the mixed carbonate-siliciclastic Qom Formation in Central Iran provides a valuable archive of depositional and tectonic changes associated with this transition. An integrated multiproxy approach was applied to reconstruct depositional environments, sequence stratigraphy, and relative sea-level variations. This approach allows for the identification of major facies associations and the influence of both global and local factors on sedimentation patterns. The results indicate that deposition occurred on a carbonate ramp, influenced by both eustatic sea-level fluctuations and synsedimentary tectonic activity. Spatial variations in terrigenous input, interpreted from facies and provenance data, indicate that synsedimentary active basement faulting segmented the basin into shallow platform and deeper ramp environments. These tectonic controls, in combination with sea-level changes strongly influenced by eustacy, governed the overall stratigraphic architecture and paleogeographic evolution of the Qom Basin.</div><div>This study provides new insights into the mechanisms that controlled the final stages of Tethyan Seaway closure, highlighting the complex interplay between regional tectonism and global climatic events in shaping Early Miocene marine basin. These findings contribute to a broader understanding of how tectonic and eustatic processes jointly influence basin evolution in marginal marine settings.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106971"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024006","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":"Diverse metamorphic P‒T‒t paths of the Mogutai tectono-metamorphic mélange, eastern Paleozoic Dunhuang Orogenic Belt, northwestern China","authors":"Yan-Lin Zhao ,&nbsp;Yichao Chen ,&nbsp;Xue-Li Jia ,&nbsp;Hui C.G. Zhang ,&nbsp;Zhen M.G. Li ,&nbsp;Longxiang Quek ,&nbsp;Chun-Ming Wu","doi":"10.1016/j.jseaes.2026.106967","DOIUrl":"10.1016/j.jseaes.2026.106967","url":null,"abstract":"<div><div>The Mogutai block, located in the eastern segment of the Paleozoic Dunhuang Orogenic Belt, northwestern China, represents a typical tectono-metamorphic mélange. It exhibits the characteristic block-in-matrix structure, with the matrix being metasedimentary rocks and the tectonic blocks consisting of amphibolite and mafic granulite. Seven representative metamorphic rocks were collected in a limited area with ∼ 1.3 km long and ∼ 1.2 km wide. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating of metamorphic zircon of these rocks reveals that the metamorphic events occurred at ∼ 462‒350 Ma. Different mineral assemblages of the metamorphic rocks were formed sequentially in the three distinct metamorphic stages, i.e., the prograde metamorphism (M1), the peak metamorphism (M2), and the retrograde metamorphism (M3). Diverse clockwise metamorphic pressure − temperature (<em>P − T</em>) paths were reconstructed by geothermobarometry, including the <em>P − T</em> paths of the mafic granulite passing from 4.6 − 6.1 kbar/630 − 650 °C (M1) through 11.9 − 16.3 kbar/710 − 830 °C (M2) and finally to 7.8 − 8.7 kbar/720 − 770 °C (M3), as well as from 6.7 kbar/720 °C (M1) through 8.0 kbar/750 °C (M2) and finally to 4.6 kbar/700 °C (M3) for the garnet amphibolite, respectively. Different peak metamorphic <em>P − T</em> conditions of the metapelitic lenses were estimated to be between 3.7 − 11.9 kbar and 610 − 780 °C. The significant differences in peak <em>P − T</em> conditions of these metamorphic rocks suggest that they were subducted to varying depths during the subduction process, and finally were amalgamated during exhumation, resulting in formation of the Mogutai tectono-metamorphic mélange.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"299 ","pages":"Article 106967"},"PeriodicalIF":2.4,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980917","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}