Journal of Asian Earth Sciences最新文献

{"title":"The formation mechanism of ultra-deep gas condensate reservoirs: A case study of the Shunbei No. 4 strike-slip fault zone in the Tarim Basin, NW China","authors":"Xin Yang ,&nbsp;Hongwei Ping ,&nbsp;Zicheng Cao ,&nbsp;Lu Yun ,&nbsp;Haiying Li ,&nbsp;Jun Han ,&nbsp;Feng Geng ,&nbsp;Cheng Huang ,&nbsp;Xinle Zhang ,&nbsp;Zhongdeng Lu ,&nbsp;Honghan Chen","doi":"10.1016/j.jseaes.2026.106986","DOIUrl":"10.1016/j.jseaes.2026.106986","url":null,"abstract":"<div><div>The Shunbei No. 4 strike-slip fault zone in the Tarim Basin represents a critical area for ultra-deep gas condensate exploration, yet the formation mechanism of gas condensate remains a subject of debate. A multidisciplinary approach integrating fluid inclusion, <em>in-situ</em> U-Pb dating, and organic geochemical analysis was employed to investigate the sources, thermal maturity, and secondary alterations of oil and gas within Ordovician reservoirs, to constrain the timing of hydrocarbon charging, and to elucidate the formation processes of gas condensate reservoirs. The results reveal that the Ordovician reservoirs experienced multi-phase tectonic events, as indicated by four generations of calcite veins. Hydrocarbon charging occurred in two stages: an early oil charge during the middle Hercynian to Indosinian periods (340–210 Ma) and a late gas condensate and natural gas charge during the Himalayan period (33–3 Ma). Crude oils were sourced from the Lower Cambrian Yurtus Formation, exhibiting medium-to-high thermal maturity (mainly 1.0–1.2% Ro), while the natural gas predominantly originated from deeper oil-cracking processes. The formation of gas condensate reservoirs in the study area was a result of early oil charging followed by late-stage oil-cracking gas injection. The activity intensity and segmentation of the strike-slip fault significantly influenced hydrocarbon enrichment. Pull-apart structures within the fault system provided favorable conditions for hydrocarbon migration and accumulation, whereas variations in fault activity intensity controlled differential oil and gas production. This study enhances the understanding of gas condensate accumulation mechanisms within ultra-deep carbonate reservoirs, offering valuable insights for future oil and gas exploration in the Tarim Basin.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"301 ","pages":"Article 106986"},"PeriodicalIF":2.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122692","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":"Evidence for shock-induced transformation and incipient melting of pyroxene in impact-melt bomb from Lonar Impact Crater, India","authors":"Kishan Tiwari ,&nbsp;Dwijesh Ray ,&nbsp;Saumitra Misra ,&nbsp;Garima Arora","doi":"10.1016/j.jseaes.2026.106997","DOIUrl":"10.1016/j.jseaes.2026.106997","url":null,"abstract":"<div><div>We present microstructural and spectroscopic evidence of shock-induced incipient melting of pyroxene in impact-melt bombs from the Lonar crater, India, formed by oblique impact on Deccan basalts. Although previous studies suggested that pyroxene remained largely in the solid state during basaltic target melting, our observations reveal pervasive fracturing, vesiculation, granular textures, and selective pyroxene-grain melting. Back-scattered electron imaging highlights marginal recrystallization, granularization, and irregular Fe-enrichment/Mg-depletion patterns, indicative of localized high-temperature effects. Micro-Raman spectroscopy documents systematic shifts and broadening of characteristic pyroxene peaks, with dendritic and vesiculated domains showing pronounced structural disorder. These trends correspond to crystallization at elevated temperatures consistent with incipient melting under ∼ 55 GPa shock pressure and ≥ 1606 K. Using heat conduction modelling of pyroxene melting timescales, we constrain the shock pulse duration and refine estimates of the impactor’s size and velocity. Our calculations suggest the Lonar crater was formed by a ∼ 193–219  m diameter chondritic projectile, impacting at an angle of 30 − 45° with an impact velocity of ∼ 5.28–5.48  km/s, generating a shock wave of sufficient intensity and duration to induce melting and structural transformation in pyroxene. These findings reconcile microstructural and thermal observations with impact dynamics and underscore the importance of pyroxene behavior in the generation and evolution of basaltic impact melts. This study provides new insights into shock metamorphism of pyroxene and its contribution to melt production in basaltic targets, with broader implications for interpreting impact processes on the Moon, Mars, and basaltic asteroids.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"301 ","pages":"Article 106997"},"PeriodicalIF":2.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122690","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":"Ediacaran separation of the North Qilian Block from the Central Qilian Block, NW China: Evidence from detrital zircon U-Pb geochronology","authors":"Lang Sun ,&nbsp;Chuan Yang ,&nbsp;Zhixin Sun ,&nbsp;Jin Luo ,&nbsp;Bing Pan ,&nbsp;Chunlin Hu ,&nbsp;Guoxiang Li ,&nbsp;Maoyan Zhu","doi":"10.1016/j.jseaes.2026.107002","DOIUrl":"10.1016/j.jseaes.2026.107002","url":null,"abstract":"<div><div>The Precambrian stratigraphic archive of the North Qilian Accretionary Belt (NQAB) is crucial for understanding the tectonic evolution of the Proto-Tethys Ocean. Although various tectonic evolution models of the NQAB have been proposed, no consensus has yet been reached due to the ambiguous Precambrian chronostratigraphic framework and tectonic nature of this belt. In this study, we present LA-ICP-MS U-Pb dates of detrital zircons from the Precambrian iron-formation-bearing Jingtieshan and Zhulongguan groups in the northwestern NQAB. The new results, together with the published dates, indicate that the depositional ages of the two groups are 1400–1230 Ma and 740–580 Ma, respectively. Meanwhile, the Precambrian stratigraphic sequences and detrital zircon age distributions show strong similarities to their age-equivalent units in the western Central Qilian Block (CQB), demonstrating a close tectonic affinity between them in Precambrian. The provenance shift in early Paleozoic, together with the Ediacaran ophiolite suites and associated rift-related basaltic rocks in the NQAB, indicates that the previously identified North Qilian Block, where the Jingtieshan and Zhulongguan groups deposited, was separated from the CQB by continental rifting and subsequent ocean spreading during the late Ediacaran. These findings shed new lights on the tectonic evolution of the Proto-Tethys Ocean in the Neoproterozoic.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"301 ","pages":"Article 107002"},"PeriodicalIF":2.4,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122691","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":"Magmatic evolution of the Karakoram Batholith, Trans-Himalaya, NW India: Geochemical insights for arc dynamics and crustal growth","authors":"Irfan M. Bhat ,&nbsp;H. Chauhan ,&nbsp;T. Ahmad ,&nbsp;T. Tanaka","doi":"10.1016/j.jseaes.2026.106989","DOIUrl":"10.1016/j.jseaes.2026.106989","url":null,"abstract":"<div><div>The Karakoram Terrane (KT), a continental block along the southern margin of the Asian Plate, originated within the <em>peri</em>-Gondwanan Cimmerian assemblage. It rifted from the Gondwana during the Permian, opened the Neo-Tethys Ocean, and accreted to southern Asia by the Early Jurassic. To constrain its tectono-magmatic evolution, we present whole-rock geochemical data from the Karakoram Batholith (KB), a major granitoid complex of the Trans-Himalaya, NW India. The KB is dominated by porphyritic granites containing abundant diorite enclaves, reflecting magma mingling between coeval mafic and felsic melts. Geochemically, KB granites and diorites exhibit calc-alkaline metaluminous characteristics typical of I-type granitoids, analogous to subduction-zone settings. KB granites have whole-rock ε_Nd(t = 110 Ma) values from -6.9 to -8.8 with Nd depleted mantle model ages (T_DM) from 1650 to 1857 Ma. Similarly, KB diorites have whole-rock ε_Nd(t = 110 Ma) values from -4.5 to -6.3 with T_DM from 1800 to 1953 Ma. These results are analogous to those of the Middle Cretaceous KB diorites (-8.2 to -7.3, and 1380 to 1650 Ma; respectively). These features indicate that during the Jurassic-Cretaceous, northward subduction of the Neo-Tethys oceanic plate beneath the southern margin of the KT established an Andean-type tectonic setting. This emplaced extensive KB magmatism derived from mixed sources, including the mantle wedge and upper crustal rocks of the KT.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106989"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174662","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":"Present-day stress characterisation in the Abadan Plain, Southwestern Iran","authors":"Rasoul Heydari ,&nbsp;Masoud Bagdeli ,&nbsp;Mojtaba Rajabi","doi":"10.1016/j.jseaes.2026.106978","DOIUrl":"10.1016/j.jseaes.2026.106978","url":null,"abstract":"<div><div>This study investigates the in-situ stress field of the Abadan Plain Basin, southwestern Iran. The Abadan Plain, unlike the surrounding areas in Zagros Fold-and-Thrust Belt, is characterised by low seismicity and a lack of surface anticlines. In this study, borehole data, including wireline logs, laboratory results of rock mechanics on core samples, Reservoir Description Tool (RDT) measurements, borehole imaging tools, and Leak-Off Test (LOT) from two boreholes were used to analyse formation pressure, stress magnitudes and orientations. One-dimensional geomechanical model was employed to estimate horizontal stress magnitudes. The Ilam Formation exhibits over-pressured regime, while the Sarvak Formation shows normal pressure behaviour. Analysis of borehole breakouts and drilling induced tensile fractures indicate that the orientation of maximum horizontal stress in the Abadan Plain Basin is predominantly ENE-WSW, which aligns with previous regional studies. The study reveals that the stress regime in the area is primarily normal faulting stress regime. This research contributes to understanding the in-situ stress state and pore pressure distribution in a region with limited data, which is essential for geomechanical modelling and petroleum exploration.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106978"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081416","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":"Genesis and mineral exploration of the Daqishan Lead-Zinc Deposit, Beishan orogenic Belt, NW China: Constraints from In-Situ trace element compositions of Sphalerite, Pyrite, and Chalcopyrite","authors":"Yu Liu ,&nbsp;Biao Jiang ,&nbsp;Jichang Zhao ,&nbsp;Zongfu Fan ,&nbsp;Peibin Xu ,&nbsp;Xudong Zhu ,&nbsp;Yinding Zhang","doi":"10.1016/j.jseaes.2026.106981","DOIUrl":"10.1016/j.jseaes.2026.106981","url":null,"abstract":"<div><div>The Daqishan deposit is located in the Beishan orogenic belt, with a Pb + Zn metal reserve of 108 kilotons, qualifying it as a medium-sized deposit. Through the field investigations and microscopic observations, this study divides the Daqishan deposit’s ore-forming process into three stages: (I) Quartz-pyrite stage; (II) Quartz + calcite + sphalerite + galena + pyrite stage; (III) Quartz + chalcopyrite + cassiterite + silver minerals stage. To explore the distribution and substitution mechanisms of trace elements in key minerals and clarify the deposit’s genesis, LA-ICP-MS was employed for in situ analysis of trace element compositions in sphalerite, pyrite, and chalcopyrite from different stages. In sphalerite, trace elements including Fe, Mn, Cd, Co, In, and Ag are mainly integrated into the mineral lattice through isomorphism. In pyrite, Co and Ni are primarily incorporated via coupled substitution, while in chalcopyrite, In, Ag, and Sn are predominantly integrated through coupled substitution. The Co/Ni ratio and As content in pyrite suggest the mineral formed in a medium- to low-temperature environment, with temperatures decreasing as mineralization advanced. The Ga/In and Zn/Cd ratios in sphalerite indicate its formation under medium- to low-temperature conditions, with higher temperatures during the main mineralization stage. Collectively, the mineralization of the Daqishan Pb-Zn deposit is inferred to result from multiple episodes of pulsed mineralization by ore-forming fluids, there remains potential for discovering copper-tin mineralization at depth and in peripheral areas of the deposit. Based on trace element characteristics of sphalerite and pyrite, the Daqishan deposit is classified as an epithermal deposit.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106981"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081415","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":"Lutetian swamp-freshwater palynoflora from Bultu-Zile (central Anatolia, Türkiye): Implications for Eocene ecosystems of Balkanatolia","authors":"Benjamin Raynaud ,&nbsp;M. Serkan Akkiraz ,&nbsp;Anaïs Boura ,&nbsp;Carina Hoorn ,&nbsp;Martha Gibson ,&nbsp;Adele Giobbini ,&nbsp;Paul Botté ,&nbsp;Leny Montheil ,&nbsp;Mustafa Kaya ,&nbsp;Faruk Ocakoğlu ,&nbsp;Deniz İbilioğlu ,&nbsp;Grégoire Métais ,&nbsp;K. Christopher Beard ,&nbsp;Pauline Coster ,&nbsp;Alexis Licht","doi":"10.1016/j.jseaes.2026.106980","DOIUrl":"10.1016/j.jseaes.2026.106980","url":null,"abstract":"<div><div>Balkanatolia is a south-eastern European biogeographic province that, during the Early and Middle Eocene, comprised low topography islands sustaining endemic mammalian fauna. The environmental and climatic context of the duration and, then, the end of this faunal endemism is still debated. Therefore, palynology could help us to characterize these environments and climates. Most Lutetian palynofloras from this region deposited in terminal fluvial settings (e.g. mangrove, deltaic, or shallow marine environments). Here, we present the first description of the palynoflora from Bultu-Zile, a Lutetian embrithopod-bearing locality in the Pontides (Türkiye). Unlike other Balkanatolian sites, the Bultu-Zile assemblage accumulated in a calm swamp-freshwater environment, preserving a distinctive pollen and spore record dominated by swamp and freshwater indicators such as Polypodiaceae, Lygodiaceae, Osmundaceae, Cupressaceae, and Ludwigia (Onagraceae). This depositional context also documents the earliest occurrences of Azolla (Salviniaceae) and Corsinipollenites oculusnoctis (Ludwigia, Onagraceae) in Türkiye. Lowland-riparian and montane indicators are also present in the assemblage (e.g. Fagaceae, Myricaceae, Cyrillaceae/Clethraceae, Juglandaceae, Mastixiaceae, Lythraceae, Sapotaceae, <em>Ilex</em>, <em>Armeria</em>, Icacinaceae, and <em>Vitaceae</em>). Quantitative climatic reconstructions using both the Coexistence Approach and CREST suggest a wet temperate climate with hot and wet summers. The Bultu-Zile palynoflora aligns with the broader Lutetian environmental and climatic framework of Balkanatolia and supports a scenario of climatic and vegetational continuity from Western Europe to Central Asia, with evergreen Fagaceae-Juglandaceae forests and mangroves along the shorelines. These findings imply that Balkanatolian faunal endemism persisted primarily due to insular isolation rather than climatic or environmental barriers.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106980"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174578","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":"A Cryogenian–Early Ediacaran volcanosedimentary record of glacial deposits in northern Saudi Arabia, Arabian–Nubian Shield","authors":"Yazhuo Niu ,&nbsp;Alan S. Collins ,&nbsp;Runlong Fan ,&nbsp;Majed N. Turkistani ,&nbsp;Ashraf Qubsani ,&nbsp;Mahrous M. Abu El-Enen ,&nbsp;Saad Al Garni ,&nbsp;Lei Guo","doi":"10.1016/j.jseaes.2026.106987","DOIUrl":"10.1016/j.jseaes.2026.106987","url":null,"abstract":"<div><div>The waning glacial influence throughout the Cryogenian is supported by the decreasing duration of the Sturtian glaciation (ca. 57 million years) and the Marinoan glaciation (&lt;15 million years). Well-preserved sedimentary sequences in the Arabian–Nubian Shield provide evidence for this decline in glaciation in low-latitude regions. The Hadiyah Group represents a Cryogenian volcanosedimentary sequence containing diamictites; however, its precise age range and glacial influence remain poorly constrained. In this study, we report a sensitive high-resolution ion microprobe zircon U–Pb age of 703.8 ± 3.8 Ma from an andesitic layer that directly underlies the diamictite bed. This age, together with maximum depositional ages derived from the sedimentary strata, indicates that the Hadiyah Group was deposited between the Cryogenian and Early Ediacaran (ca. 703.8–620.3 Ma). Abraded conchoidal fracture steps on quartz grains within the diamictites indicate the glacial influence from ca. 703.8 Ma to &lt;664.9 Ma, interpreted as related to the Sturtian glaciation. In contrast, the upper part of the Hadiyah Group was deposited during the Late Cryogenian and Early Ediacaran (ca. &lt;655.5–620.3 Ma), but no evidence of the Marinoan glaciation is observed. The absence of Marinoan glacial deposits may reflect either a sedimentary hiatus or an ice-free environment on the Arabian Shield.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106987"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174661","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":"A comparative machine learning framework for earthquake damage mapping in Turkey: incorporating MARS and ensemble models in the 2023 Kahramanmaraş earthquake using high-resolution Pléiades imagery","authors":"Ömer Kaya ,&nbsp;Semih Kuter ,&nbsp;Zuhal Akyürek","doi":"10.1016/j.jseaes.2026.106984","DOIUrl":"10.1016/j.jseaes.2026.106984","url":null,"abstract":"<div><div>Earthquakes cause severe damage to buildings and infrastructure, posing risks to humans and disrupting urban systems. Traditional ground-based assessments are slow and often impractical in dense urban areas. This study evaluates several machine learning algorithms for detecting damaged buildings after the 6 February 2023 earthquakes in southeastern Turkey, focusing on the city center of Hatay, one of the most affected regions. High-resolution post-event Pléiades imagery and building footprints were used to create training and test datasets covering more than 8,000 structures, and textural features extracted from the imagery served as predictors. We tested artificial neural network (ANN), random forest (RF), support vector machine (SVM) with different kernels, ensemble learners, and multivariate adaptive regression splines (MARS). To our knowledge, this is the first application of MARS to post-earthquake damage mapping using very high-resolution optical data. Model performance was assessed using 10-fold cross-validation, overall accuracy (OA), and F1 score. RF reached high training accuracy (∼0.95) but showed limited generalization. SVM with an RBF kernel behaved similarly, while polynomial SVM (degree 2) performed the worst. MARS produced moderate but stable results across folds. ANN and linear SVM showed comparable performance, with slightly higher stability for the latter. The ensemble model yielded the best test results (OA = 0.59, F1 = 0.66), offering a balance of accuracy, robustness, and computational efficiency. Although accuracies remained modest, the workflow can generate a usable damage map within 1–2 h after acquiring the post-event Pléiades image, making it suitable for rapid first-pass screening in operational settings.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106984"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174665","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":"Geochemical constraints on the evolution and tectonic setting of United Arab Emirates Ophiolitic Serpentinites","authors":"Mabrouk Sami ,&nbsp;Hamed Gamaleldien ,&nbsp;Theodoros Ntaflos ,&nbsp;Chun-Feng Li ,&nbsp;Ioan V. Sanislav ,&nbsp;Xun Zhao ,&nbsp;Vandi Dlama Kamaunji ,&nbsp;Bahaa M. Amin ,&nbsp;Douaa Fathy ,&nbsp;Mostafa R. Abukhadra ,&nbsp;Khaled Abdelfadil ,&nbsp;Suhail S. Alhejji","doi":"10.1016/j.jseaes.2026.106990","DOIUrl":"10.1016/j.jseaes.2026.106990","url":null,"abstract":"<div><div>Serpentinites in fore-arc settings provide critical constraints on mantle depletion, redox evolution, and slab–mantle fluid transfer during subduction initiation. In the northern Semail Ophiolite of the United Arab Emirates, serpentinites of the Jabal Mundassah–Malaqet (JMM) are studied using mineral chemistry, whole-rock geochemitry, and platinum-group element (PGEs) compositions to constrain protolith characteristics, melting history, and tectono-magmatic evolution. The rocks comprise massive and foliated serpentinites dominated by intergrown lizardite and antigorite with relict Cr-spinel and altered olivine. The JMM serpentinites are characterized by high MgO (34.9–39.2 wt.%), extremely low Al₂O₃ (0.21–0.92 wt.%) and TiO₂ (0.01–0.03 wt.%), elevated Ni (up to 2462 ppm) and Cr (up to 3143 ppm), and very low high-field-strength element (HFSE) and Th–U contents. These features indicate a highly refractory dunite–harzburgite protolith formed by extensive melt extraction. This interpretation is reinforced by Cr-spinel compositions (Cr# = 0.42–0.48; Mg# = 0.58–0.61) and low total PGE abundances (ΣPGE ≈ 15–35 ppb), which are diagnostic of a strongly depleted, sulfide-exhausted mantle residue. Pronounced depletion in HFSE coupled with diagnostic Nb–Th systematics definitively fingerprints a supra-subduction zone (SSZ) fore-arc tectonic setting. PGE systematics (ΣPGE ≈ 8–26 ppb; modest Pt–Pd enrichment over Os–Ir–Ru; low Pd/Ir=1.18-1.61) record moderate partial melting followed by selective mobilization of PPGEs during serpentinization, preserving a dominantly magmatic signature with a limited metasomatic overprint. We propose the JMM serpentinites originated as a highly depleted mantle residue during intra-oceanic subduction initiation. It was subsequently serpentinized by slab-derived fluids under fore-arc conditions before being tectonically emplaced onto the Arabian margin during Late Cretaceous ophiolite obduction. Relative to the main Semail mantle section, the JMM captures an earlier, less-evolved snapshot of fore-arc development during Late Cretaceous obduction, refining models for Neo-Tethyan subduction initiation and ophiolite assembly.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"300 ","pages":"Article 106990"},"PeriodicalIF":2.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174659","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}