Journal of Asian Earth Sciences最新文献

{"title":"Texture and geochemistry of magnetite from the Jinshandian deposit, eastern China: Implications for the formation of high-grade Fe ore in skarn system","authors":"Qiaoqiao Zhu,&nbsp;Guiqing Xie,&nbsp;Qian Wang,&nbsp;Kejun Hou,&nbsp;Lifan Lu","doi":"10.1016/j.jseaes.2025.106624","DOIUrl":"10.1016/j.jseaes.2025.106624","url":null,"abstract":"<div><div>Iron skarn deposits represent significant sources of high-grade Fe ores, although the mechanisms underlying their efficient enrichment in Fe are not yet fully understood. To investigate the enrichment processes of Fe in the skarn system, texture and geochemistry of magnetite from the Jinshandian Fe deposit located in eastern China were analyzed. Disseminated, friable, and massive ore types are identified at Jinshandian. The friable ore is characterized by loose structure, with minimal or absent cementation minerals interspersed among subhedral to euhedral magnetite crystals. The magnetite at Jinshandian displays significant textural heterogeneity, highlighted by macro- and nanoscale inclusions. Overgrowth and dissolution-reprecipitation (DRP) textures were locally recorded in magnetite. Magnetite grains contains low concentrations of Ti and V, alongside relatively higher Mg, Si, and (Ca+) Al+Mn. Most magnetite grains fall within the skarn field when plotted on geochemical discriminant diagrams. These findings, in conjunction with robust geological evidence, suggest that the Jinshandian deposit originates from intense water–rock interactions. The trace elements in magnetite from the friable ore exhibit similarities to those in disseminated and massive ores, indicating that the friable ore likely formed through a structural softening process that removed soluble cementing minerals (e.g., anhydrite/gypsum and calcite) from the disseminated or massive ore. A comparative analysis of Fe skarn deposits in the Edong district suggests that multiple mechanisms, including accumulation, structural softening, DRP, and superposition processes, may have significantly contributed to the formation of high-grade Fe ores within the skarn system, despite the primary controlling factors varying from one deposit to another.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"290 ","pages":"Article 106624"},"PeriodicalIF":2.7,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877528","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":"Kinematic flow and temperature variation within the Three Pagodas shear Zone, western Thailand","authors":"Sittiporn Kongsukho,&nbsp;Pitsanupong Kanjanapayont","doi":"10.1016/j.jseaes.2025.106572","DOIUrl":"10.1016/j.jseaes.2025.106572","url":null,"abstract":"<div><div>The deformation of mineral grains in mylonitic rocks enables the direct calculation of strain patterns, vorticity analysis, and deformation temperatures in the shear zones. Quartzite mylonite rocks from the Three Pagodas shear zone, western Thailand, were analyzed for finite strain, flow vorticity, and estimate deformation temperatures. Our results indicate deformation temperatures ranging from 510 °C to 570 °C in the central zone, and from 320 °C to 450 °C in the western and eastern zones. The finite strain (R_s) varied from 1.86 to 2.63. Mean kinematic vorticity number (W_m) was determined using two different methods—the porphyroclast aspect ratio (PAR) and the rigid grain net (RGN). W_m values ranged from 0.80 to 0.90, with 59 % to 71 % simple shear and 29 % to 41 % pure shear. A comparison of these zones suggests a transition in strain variation from the eastern to the western zones, with a noticeable increase in strain approaching the central zone. The S values ranged from 0.57 to 0.65 in the western zone, 0.70 to 0.75 in the central zone, and 0.65 to 0.72 in the eastern zone. Our findings confirm that the internal structure of the Three Pagodas shear zone exhibits the heterogeneous distribution, demonstrating sinistral transpressional slip with strain partitioning of general shear and distributed simple shear components at the center of the shear zone. The exhumation and cooling of the Thabsila metamorphic complex were likely influenced by two distinct phases of the India-Eurasia collision during the Early Cenozoic: Early Eocene transpression followed by Late Eocene–Early Oligocene strike-slip deformation.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"289 ","pages":"Article 106572"},"PeriodicalIF":2.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850596","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":"Reconstruction of the Late Holocene environments in the northern Minusinsk Basin (South Siberia) based on the palynological analysis of Lake Shira sediments","authors":"Elena V. Bezrukova ,&nbsp;Svetlana A. Reshetova ,&nbsp;Alexander A. Shchetnikov","doi":"10.1016/j.jseaes.2025.106610","DOIUrl":"10.1016/j.jseaes.2025.106610","url":null,"abstract":"<div><div>We present the results of a multiproxy study of a 144 cm long core of laminated sediments from Lake Shira in the northern Minusinsk Basin in order to understand the causal relationships between climate change, ecological responses, and hydrological variations. The new palynological record covers the last 2980 years with an average resolution of 21 years. Palynological results and biome scores indicate that steppe and meadow-steppe with sparse forests prevailed in the northern Minusinsk Basin during the Late Holocene. The lower part of the taiga belt in the mountainous frame of the basin was dominated by larch, and the middle part of the taiga belt was dominated by larch, pine, fir, and spruce. The gradually decreasing role of dark conifers indicates a regional trend towards climatic aridification in the Late Holocene. The ratio of Artemisia pollen to Chenopodiaceae pollen suggests that the semiarid climate of the northern Minusinsk Basin during the last 2980 years was repeatedly interrupted by short intervals of more humid climate. The low abundance of <em>Botryococcus</em> in the records from Lake Shira may be an indicator of lowered lake levels during the intervals of lake holomictic state ca. 2850–2800, 2000–1920 BP, 1320–1290 BP, 700–510 BP, and 120–70 BP. Comparison of new environmental records of the northern Minusinsk Basin obtained from Lake Shira with data on global climate fluctuations shows that changes in the regional vegetation and hydroclimate of Lake Shira in the Late Holocene were mainly caused by large-scale atmospheric circulation processes controlling the heat and moisture balance in South Siberia.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"289 ","pages":"Article 106610"},"PeriodicalIF":2.7,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835379","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, enrichment mechanism, and mineralization age of REY-rich phosphorites: A case study of the Early Cambrian Kunyang and Dongchuan phosphorite deposits, SW China","authors":"Junyi Wang ,&nbsp;Pei Liang ,&nbsp;Li Chen ,&nbsp;Zuowen Dai","doi":"10.1016/j.jseaes.2025.106608","DOIUrl":"10.1016/j.jseaes.2025.106608","url":null,"abstract":"<div><div>Sedimentary phosphorites have been recently found to have substantial concentrations of rare earth elements (REE) and yttrium (i.e., REY) which are considered strategic metals for advancing new energy and high-tech industries. This study investigates the REY enrichment mechanisms and mineralization age of REY-rich phosphorites in the Kunyang and Dongchuan phosphorite deposits using in-situ analysis of collophanite. Based on hand specimens and microscopic observations, the studied phosphorites are categorized into three types: clastic phosphorite (Type I), massive phosphorite (Type II), and striped phosphorite (Type III). The U-Pb dating of Early Cambrian phosphorites from the Kunyang deposit (Yunnan Province, SW China) yielded ages of 529.2 ± 14.8 Ma for the upper phosphorite layer and 535.1 ± 25.6 Ma for the tuff interlayer. The REY indices (e.g., La_N/Yb_N, Ce/Ce*, Eu/Eu*, and Y/Ho) and in-situ REY mapping indicate that diagenetic is the primary REY enrichment mechanism in both deposits. Additionally, the sub-oxidized depositional environment and reworking processes impacted REY enrichment. Hydrothermal alteration in the Kunyang phosphorites minimally affected the REY content but altered the REY pattern, whereas in the Dongchuan phosphorites, hydrothermal activity enhanced REY enrichment without altering the REY pattern. The phosphorites likely formed in a marine environment, with REY primarily sourced from seawater, while terrigenous clasts further contributed to the REY composition.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"289 ","pages":"Article 106608"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828676","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":"Geochronology and geochemistry of the Hatu ophiolite in the East Kunlun Orogenic Belt, northern Tibetan Plateau: Constraints on the Proto-Tethys Ocean","authors":"Zengshuai Zuo ,&nbsp;Yunpeng Dong ,&nbsp;Dengfeng He ,&nbsp;Shengsi Sun ,&nbsp;Bo Hui ,&nbsp;Bin Zhang ,&nbsp;Fubao Chong ,&nbsp;Qiwen Dai ,&nbsp;Yongcheng Li ,&nbsp;Jinyu Xiao ,&nbsp;Shengyi Xu","doi":"10.1016/j.jseaes.2025.106614","DOIUrl":"10.1016/j.jseaes.2025.106614","url":null,"abstract":"<div><div>The Early Paleozoic ophiolites exposed within the Aqikekulehu-Kunzhong ophiolitic mélange zone of the East Kunlun Orogenic Belt (E-KOB) in the northern Tibetan Plateau offer vital clues regarding the tectonic evolution of Proto-Tethys Ocean and subduction-accretionary process of the E-KOB. The Hatu ophiolitic mélange, contains a series of ophiolitic blocks and matrix (meta-) clastic rocks. Detailed field investigations reveal that the ophiolitic blocks, termed as the Hatu ophiolite, consist of gabbro, diabase and basalt. All of the mafic rocks are featured by low total REE (22.61–45.92 ppm), the flat chondrite-normalized REE patterns, slight LREEs enrichment with (La/Yb)_N = 1.07–1.28. The positive zircon ε_Hf(t) values of the gabbro and basalt range from + 11.72 to + 14.29 and from + 4.10 to + 10.93, respectively. Geochemical data indicates that all mafic rocks exhibit normal mid-ocean ridge basalt (N-MORB) properties, with their parental magmas originating from a depleted mantle source. Zircon U-Pb dating results show that two gabbro samples yield consistent weighted mean ages of 421 ± 2.9 Ma and 426 ± 4.9 Ma, while the weighted mean age of basalt is 426 ± 5.9 Ma, indicating the magmatic component of the ophiolite was formed at 426–421 Ma. The comprehensive evidence, encompassing integrated geological, geochemical and chronological data, suggests that the gabbro, diabase and basalt blocks of Hatu ophiolite are most likely the Early Paleozoic oceanic fragments having N-MOR affinities. The new evidence indicates that the Proto-Tethys Ocean in the E-KOB experienced mid-ocean ridge spreading during the Silurian.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"289 ","pages":"Article 106614"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828510","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":"Petrogenesis of the early-middle Paleozoic granites in northern Wuyi, South China: Implications for the geodynamic process of the Wuyi-Yunkai orogen","authors":"Mengyu Tian ,&nbsp;Longming Li ,&nbsp;Xilin Zhao ,&nbsp;Kang Xu ,&nbsp;Yang Liu","doi":"10.1016/j.jseaes.2025.106616","DOIUrl":"10.1016/j.jseaes.2025.106616","url":null,"abstract":"<div><div>The Early Paleozoic igneous rocks are extensively distributed across the Cathaysia Block, documenting the Wuyi-Yunkai orogeny in South China. However, the detailed geodynamic process of this orogen remains unclear. To elucidate this tectonic history, we conducted an in-depth investigation of two significant granitic plutons in northern Wuyi. LA-ICP-MS zircon U-Pb dating reveals that the Huangdun pluton was emplaced during the early Silurian (435 – 434 Ma), whereas the Jiaoxi pluton was formed during the early Devonian (401 – 398 Ma). The Huangdun monzogranites characterized by high silica content, predominantly metaluminous to peraluminous nature, low FeO^T/MgO ratios (2.21 – 2.83) and normative-CIPW corundum values (C = 0.48 – 4.72 wt%), closely resembling I–S transformation-type granites. They show relatively low initial ⁸⁷Sr/⁸⁶Sr ratios (0.7053 – 0.7077), ε_Nd(t) values (−6.6 to − 6.2), and zircon ε_Hf(t) values (−6.6 to − 0.6). These geochemical and isotopic signatures suggest that these granites were formed through partial melting of metasedimentary and <em>meta</em>-mafic rocks. In contrast, the Jiaoxi two-mica granites are rich in silica, peraluminous, with elevated FeO^T/MgO ratios (3.94 – 4.98) and high differentiation index values (88.6 – 93.4), indicating their classification as fractionated S-type granites. They display variable ε_Hf(t) values (−15.1 to + 0.6) and low ε_Nd(t) values (−7.0 to − 5.9). These features suggest that they were derived from partial melting of metasedimentary rocks. Integrating these findings with previous research, including the presence of Early Paleozoic MOR-type ophiolites, we propose that the Wuyi-Yunkai orogen as a subduction-collisional orogen. The Huangdun granites were formed during the <em>syn</em>-collisional stage in the early Silurian, while the Jiaoxi granites were generated during the post-collisional extension stage in the early Devonian.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106616"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829165","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 geochronology of the Bayanteeg Li-mineralized pegmatite in the Idermeg terrane, central Mongolia","authors":"Khashbat Dashtseren ,&nbsp;Bolorchimeg N. Tunnell ,&nbsp;Enkhjargal Boldbaatar ,&nbsp;Jargalan Sereenen ,&nbsp;Marek Locmelis ,&nbsp;Yueheng Yang ,&nbsp;Ming Yang ,&nbsp;Willis Hames ,&nbsp;Nobuhiko Nakano ,&nbsp;Tatsuro Adachi","doi":"10.1016/j.jseaes.2025.106615","DOIUrl":"10.1016/j.jseaes.2025.106615","url":null,"abstract":"<div><div>We present the first petrographic, lithogeochemical, and geochronological study of the Bayanteeg LCT pegmatite located in Idermeg terrane, central Mongolia, and interpret the findings within the geodynamic setting. The pegmatite extends over 140 m with a width of 1.3 m and unknown depth within Neoproterozoic gneiss. The pegmatite contains plagioclase, quartz, and lepidolite with minor K-feldspar, spodumene, muscovite, and topaz, and accessory amounts of cassiterite, amblygonite, columbite-tantalite, monazite, zircon, apatite, and fluorite. Locally, minor secondary quartz and lepidolite occur interstitially between plagioclase and quartz and along the edges of primary lepidolite, respectively, implying late-stage hydrothermal influence. Lithogeochemical data show that the pegmatite contains 0.3–1.12 wt% Li, 256–1285 ppm Cs, and 59–522 ppm Ta. Monazite U-Th-Pb geochronology yielded an age of 144.9 ± 2.8 Ma while cassiterite yielded a U-Pb age of 134.8 ± 1.4 Ma. Lepidolite yielded ⁴⁰Ar/³⁹Ar plateau age of 131.25 ± 0.3 Ma. These age results fall during the geodynamic evolution of an intracontinental extension accompanied by the exhumation of metamorphic core complexes and extensive magmatism in the eastern Central Asian Orogenic Belt. These events occurred due to a combination of gravitational collapse resulting from lithospheric delamination and asthenospheric upwelling. The geodynamic setting during the pegmatite emplacement implies abnormally hot conditions, ruling out the possibility of anatectic origin. The pegmatite dike with elevated concentrations of Be, Ga, Rb, Nb, Sn, Cs, Ta, and Tl supports a granitic origin with a hidden parental granite at depth. The fact that the Idermeg terrane contains several LCT pegmatites implies an important exploration target for Li exploration.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106615"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833170","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 evidence for Late Eocene to Oligocene climate change in the Lühe Basin of the southeastern Tibetan Plateau","authors":"Hao Cui ,&nbsp;He Tang ,&nbsp;Zhifeng Liu ,&nbsp;Jianghao Bai ,&nbsp;Juncai Chen ,&nbsp;Gangjian Wei","doi":"10.1016/j.jseaes.2025.106612","DOIUrl":"10.1016/j.jseaes.2025.106612","url":null,"abstract":"<div><div>The transition from the Eocene to the Oligocene marks a critical phase in Earth’s history, characterized by a shift from greenhouse to icehouse conditions. While global climate changes during this period have been extensively studied, continental geological evidence particularly from landmasses such as the Tibetan Plateau (TP) and its surrounding regions remained limited. Addressing this research gap, our study employs high-resolution trace element geochemical records from the Lühe Basin at the southeastern margin of the Tibetan Plateau (SEMTP) to systematically investiate sediment provenance and weathering processes from the Late Eocene to the Oligocene (35.5–25.5 Ma). The results indicate that the sediment provenance in the Lühe Basin shows limited variation across different scales of provenance analysis, and lithological have little effect on the reconstruction of chemical weathering records. Based on various geochemical proxies, three distinct phases in the evolution of weathering are identified: (1) a phase of progressively intensified weathering during the Late Eocene, (2) a marked decline in weathering intensity during the Eocene-Oligocene Transition (EOT), and (3) a phase of recovery followed by sustained fluctuations in the Oligocene. Furthermore, we discuss the potential global climatic and regional environmental drivers underlying each phase.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106612"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823385","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":"Depositional framework of the Sangkarewang and Sawahlunto Formations, Ombilin Basin, West Sumatra, Indonesia","authors":"J-P. Zonneveld ,&nbsp;V.D. Barreda ,&nbsp;Y. Zaim ,&nbsp;Aswan ,&nbsp;Y. Rizal ,&nbsp;A.T. Hascaryo ,&nbsp;R.L. Ciochon ,&nbsp;J. Head ,&nbsp;A. Murray ,&nbsp;T. Smith ,&nbsp;P. Wilf ,&nbsp;J.I. Bloch","doi":"10.1016/j.jseaes.2025.106611","DOIUrl":"10.1016/j.jseaes.2025.106611","url":null,"abstract":"<div><div>Analyses of rock samples collected during recent fieldwork in the Ombilin Basin of west-central Sumatra, Indonesia yielded pollen data that constrain the age and depositional setting of associated plant macrofossil and vertebrate fossil-bearing units in the Sangkarewang and Sawahlunto formations. Articulated fish and plant fossils were recovered from bedding plane surfaces of fissile, laminated shales in the Sangkarewang Formation that are interpreted to have been deposited in an actively-subsiding, deep, anoxic lake. The overlying Talawi Member of the Sawahlunto Formation records stratigraphy consistent with deposition in a segue to marginal lacustrine marsh and poorly-drained paleosol settings. Interbedded carbonate mudstone / wackestone and lignitic claystone units in the basal Talawi Member preserve scattered, disarticulated fossils of fish, reptiles, an amphibian, and one mammal tooth. These beds grade into a heterolithic succession of fine-grained clastic rock, with coal interbeds likely deposited in a coastal alluvial setting. Marine influences in this interval are indicated by the nature of physical sedimentary structures in several zones, the presence of trace fossils such as <em>Diplocraterion, Cylindrichnus</em> and <em>Teichichnus,</em> and the occurrence of foraminiferal linings, dinocysts and other palynomorphs indicative of mangrove and back-mangrove settings. Palynological analysis indicates that the most probable age of the Sawahlunto Formation ranges from the middle to late Eocene, with a possible extension from the middle Eocene to the early Oligocene.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106611"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843669","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":"Tectonic variations in NS-trending rifts, southern Tibetan Plateau: insights from hydrothermal emissions and seismic activities","authors":"Jiao Tian ,&nbsp;Xiaocheng Zhou ,&nbsp;Minghui Liao ,&nbsp;Miao He ,&nbsp;Zhaojun Zeng ,&nbsp;Yucong Yan ,&nbsp;Bingyu Yao ,&nbsp;Yuwen Wang ,&nbsp;Shihan Cui ,&nbsp;Gaoyuan Xing ,&nbsp;Chunhui Cao ,&nbsp;Liwu Li ,&nbsp;Changhui Ju","doi":"10.1016/j.jseaes.2025.106599","DOIUrl":"10.1016/j.jseaes.2025.106599","url":null,"abstract":"<div><div>A series of NS-trending rifts in the Tibetan Plateau interior provide a window for unraveling its rifting properties and geodynamic mechanisms. In this study, we focused on hydrothermal degassing and seismic activities to identify the differential tectonic status of each rift. Analysis of hydrothermal gaseous components reveals that crustal metamorphic products accumulate in the western rifts and the easternmost rift while growing mantle-derived volatiles contribute in the northeast rifting zones. The flow rate of uprising mantle-derived fluids ranges from 0.01 mm/yr to 2972 mm/yr and the total ³He fluxes vary in 1.0 × 10⁻⁷ – 1.2 × 10⁻⁵ mol/km²/yr. The distribution of H₂-enriched hot springs coincides with the young initiation time of the rifts, indicating the young active tectonic setting in the eastern rifts. Spatially discernible characteristics are also observed in seismic activity. Earthquakes occurring in western rifts have relatively shallow focal depths and low frequencies and magnitudes, suggesting that faulting structures are active within the middle-shallow crust. In contrast, more frequent strong and deep-focus earthquakes occurred in the northeastern rifting areas, outlining the large-scale fault planes that dipped into the lower crust or even the bottom of the lithosphere and served as an enhanced conduit for the growing contribution of mantle-derived volatiles at the surface. Our interpretation emphasizes that the underlying Indian slab is unlikely to experience wide tearing beneath Tibet and that eastward-enhanced seismic activity and degassing are likely driven by eastward-propagating lateral slab detachment. These findings have profound implications for the post-collisional evolution of the Tibetan Plateau.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106599"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823579","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}