Journal of Asian Earth Sciences最新文献

{"title":"Lithofacies and microfacies analysis and sequence stratigraphic architecture of the Upper Cretaceous carbonate complex in the Wadi Sirhan Basin, SE Jordan","authors":"Mohamed Kh. Khalifa ,&nbsp;Kingsley J. Mills ,&nbsp;Hezam Al-Awah ,&nbsp;Wael Matter","doi":"10.1016/j.jseaes.2025.106803","DOIUrl":"10.1016/j.jseaes.2025.106803","url":null,"abstract":"<div><div>This research integrates a detailed sedimentary facies characterisation, associated with a depositional environment reconstruction, all of which is placed in a sequence stratigraphy framework on the stratigraphic development of the Upper Cretaceous Ajlun Group carbonates succession from the Zgaimat Al-Hasah outcrop and Wadi Sirhan-2 well sections, across the southeastern part of the Wadi Sirhan Basin, SE Jordan. The outcrop-subsurface correlation indicated that these Upper Cretaceous Ajlun Group carbonate successions correspond to the undifferentiated Naur, Fuheis, Hummar and Shueib formations and Wadi Sir Formation in the study area. The first result was the delineation of surface and subsurface stratigraphy of the Upper Cretaceous Ajlun Group divided into five distinctive lithostratigraphic intervals (A, B, C, D and E, in ascending order) based on the factors controlling the lithologic features such as rock samples from outcrop supplemented by core and cutting data. The second result is the recognition of nine distinct facies belts containing several microfacies types defined by variations in lithologic types, fossil distribution, sedimentary texture and variations in color of these sediments in lateral and vertical changes. The third result indicates a sequence stratigraphic framework of the Upper Cretaceous Ajlun Group section, characterised by two third-order depositional sequences (Ajlun Group depositional sequence-I “AGPDS-I” and Ajlun Group depositional sequence-II “AGPDS-II”, respectively) that are identified from changes in systems tracts patterns composed of transgressive system tract-1, 2, and highstand system tract-1, 2. Correlation of the lithostratigraphic interval relationships and two depositional sequences of the Ajlun Group carbonate systems and development of complex lithological types have implications for evaluating the outcrop analogy with the subsurface geology and hydrocarbon prospectivity of the Wadi Sirhan Basin and adjacent areas in central and southeastern Jordan.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106803"},"PeriodicalIF":2.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266670","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 carboniferous plagiogranites within serpentinite mélange, northern Thailand: Implications for the tectonic evolution of the Nan-Uttaradit Suture","authors":"Jongkonnee Khanmanee ,&nbsp;Qinglai Feng ,&nbsp;Tianyu Zhao ,&nbsp;Xiaomei Nie ,&nbsp;Jiabo Hu ,&nbsp;Zhengqin Gan ,&nbsp;Thakoon Makkhun ,&nbsp;Pakkapong Sribuatong ,&nbsp;Nalinee Thanun ,&nbsp;Tanakit Teja ,&nbsp;Kanokporn Phromkhan ,&nbsp;Punya Charusiri","doi":"10.1016/j.jseaes.2025.106800","DOIUrl":"10.1016/j.jseaes.2025.106800","url":null,"abstract":"<div><div>The oceanic plagiogranites within the ophiolite suites play an important role in understanding the evolution of ancient ocean basins. Late Carboniferous plagiogranites were first identified within the Nan-Uttaradit Suture, north Thailand. The LA-ICP-MS zircon U-Pb analyses of Mae Charim plagiogranites yielded two concordant zircon U–Pb ages of 320 ± 2 Ma and 302 ± 2 Ma. Geochemically, they are characterized by high SiO₂, Al₂O₃ and Na₂O contents, and low K₂O and TiO₂ contents, with high Mg#, Na₂O/K₂O ratios and positive Eu anomalies. They also exhibit low REE concentrations with enrichment in MREEs and LILEs, as well as depletion in HFSEs. The Mae Charim plagiogranites show highly positive ɛ_Hf(t), indicating an origin from a depleted mantle source. These geochemical signatures are consistent with those of typical oceanic subduction-type plagiogranites. We propose that these plagiogranites were formed by hybridization of melts derived from partial melting of the subducted oceanic slab and their interaction with the overlying mantle wedge. Based on these new data, it is concluded that the Nan-Uttaradit Ocean was connected with the Jinshajiang-Ailaoshan-Song Ma-Song Chay and Luang Prabang Oceans during the Late Ordovician to Late Triassic. Thus, we propose that the Nan-Uttaradit Ocean was a branch of the Paleo-Tethys Ocean, but not a back-arc basin of the Chiang Mai Paleo-Tethys Ocean.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106800"},"PeriodicalIF":2.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158021","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 of post-tectonic granite and granitic gneiss of the Central Indian Tectonic zone, India: Implications for the timing of amalgamation of the North and South Indian Blocks","authors":"Sarada Prasad Mohanty ,&nbsp;Qiuli Li ,&nbsp;Mingguo Zhai ,&nbsp;Anup Krishna Prasad ,&nbsp;Jayanata Topno ,&nbsp;Sangitsarita Nanda","doi":"10.1016/j.jseaes.2025.106799","DOIUrl":"10.1016/j.jseaes.2025.106799","url":null,"abstract":"<div><div>Investigations in collisional orogens involved in polyphase deformation, high-grade metamorphism, partial melting of rocks and fluid-flow regimes have constraints on data interpretation, particularly regarding the time of primary magmatism and later melting. Zircon geochronological investigations were carried out on granites and granitic gneisses of the Central Indian Tectonic Zone (CITZ) of India to resolve the problem regarding the timing of the collisional events. A granite gneiss previously mapped as the basement for the Sausar Group or as a <em>syn</em>-tectonic (<em>syn</em>-orogenic) intrusion in the Sausar Group provided U-Pb age of 1296 ± 6 Ma, and results from another post-tectonic (post-orogenic) granite emplacement in the Sausar Group gave U-Pb age of 933 ± 7 Ma. While the age of the latter defines a bench-mark point for the time limit of compressional tectonics in the region, the age of the former is much older than the previously identified time of amalgamation between the North and South Indian Blocks along CITZ at ∼ 1040 Ma. The discrepancy for time of emplacement of the granite gneiss was scrutinised by analysing the map pattern of the gneiss and the metasedimentary rocks bordering it, available <em>P-T</em> path for CITZ, high-precision zircon geochronological data from CITZ and about 94 geochemical analyses of granite gneisses in CITZ along with the data generated for the analysed granites. These multi-pronged approaches provided additional bench-mark points in the tectonic evolution of CITZ. The geochronological results from the granite gneiss do not support the previous suggestion regarding amalgamation of blocks along CITZ during the “Grenvillean Orogeny” at ∼ 1040 Ma.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106799"},"PeriodicalIF":2.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158018","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 Permian strike-slip tectonics in the northern North China Craton: new insights from geological and geophysical data of the Longwangmiao granitic pluton","authors":"Chao Song ,&nbsp;Wei Lin ,&nbsp;Wei Wei ,&nbsp;Lingtong Meng ,&nbsp;Yang Chu ,&nbsp;Qinying Wu ,&nbsp;Zhao Guo ,&nbsp;Yin Wang ,&nbsp;Ran An ,&nbsp;Fei Liu ,&nbsp;Jinhui Yang","doi":"10.1016/j.jseaes.2025.106801","DOIUrl":"10.1016/j.jseaes.2025.106801","url":null,"abstract":"<div><div>In order to better understand the late Permian tectonic setting in the northern part of the North China Craton (NCC), the emplacement mechanism of the Longwangmiao pluton which preserves evidence of regional tectonic framework during magma emplacement has been investigated. A multidisciplinary study including structural observations, anisotropy of magnetic susceptibility (AMS), gravity modeling, and geochronology was conducted on this granitic pluton. According to the structural analysis, planar and linear structures are poorly developed. The rock exhibits magmatic to sub-magmatic microstructures. The magnetic foliations are highly concentrated with dominant NE-SW strikes and steep dips, and the magnetic lineations are clustered in the NE-SW direction with a wide range of plunge angles. Magnetic foliations are outward dipping, revealing a magmatic domal pattern. Gravity modeling documents the feeder zone has an elliptical outline with a NW-SE long axis. Differing from previous arc-related or post-collisional extensional plutons, the Longwangmiao pluton is considered a syn-tectonic intrusion emplaced within regional strike-slip tectonics, in which the E-W trending dextral strike-slip shearing resulted in NW-SE shortening and NE-SW stretching. Based on new geochronological data and regional tectonic analyses, the giant dextral strike-slip fault system in the northern part of the NCC may either be related to the manifestation of continuous intra-continental adjustment following the Central Asian Orogenic Belt formation or represent the easternmost segment of the Intra-Pangea Megashear.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106801"},"PeriodicalIF":2.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096040","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":"Changes of the Carpinus cordata distribution in the south of the Russian Far East during the Late Pleistocene and the Holocene by pollen data","authors":"Pavel S. Belyanin","doi":"10.1016/j.jseaes.2025.106783","DOIUrl":"10.1016/j.jseaes.2025.106783","url":null,"abstract":"<div><div>The aim of the present work is to reconstruct changes of the spatial distribution of <em>Carpinus cordata</em> near the modern northern limit of its range in the south of the Russian Far East in the Late Pleistocene and Holocene, based on 75 pollen records, 130 radiocarbon and 3 uranium-ion dates. We found that <em>Carpinus cordata</em> grew in the Southern Primorye during MIS 5e, MIS 5d and MIS 5a. Under the warm climate conditions of MIS 5e, the range of this plant could have expanded to more northern regions. <em>Carpinus cordata</em> might also grew in the region during MIS 5e and MIS 5b. <em>Carpinus cordata</em> did not grow in the south of the Russian Far East during MIS 3, MIS 2, and apparently in MIS 4. Intensive warming during the MIS 2 to MIS 1 transition triggered a northward shift in the range of <em>Carpinus cordata.</em> Approximately 10.4 ka cal BP, the northern limit of its range reached the Southern Primorye. Around 8.7 ka cal BP, the <em>Carpinus cordata</em> reached the Central Primorye and began expansion in it. During the Mid-Holocene Thermal Maximum, its range covered Central Primorye and extended to the southernmost part of Northern Primorye. The cooling at the onset of the Late Holocene led to the disappearance of <em>Carpinus cordata</em> from Central Primorye. Under subsequent warming in the second half of the Late Holocene, the range of this plant shifted slightly to the north. However, it no longer covered the Northern Primorye and the Central Primorye.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"293 ","pages":"Article 106783"},"PeriodicalIF":2.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219795","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":"Ore-forming mechanism of high-grade iron ore in Qidashan iron deposit, Liaoning Province: insights from the columbite-group minerals in granite and altered rocks","authors":"Yu-zeng Yao,&nbsp;Chang-ming Wei,&nbsp;Jing Liu,&nbsp;Jian-fei Fu,&nbsp;Sheng Xu","doi":"10.1016/j.jseaes.2025.106791","DOIUrl":"10.1016/j.jseaes.2025.106791","url":null,"abstract":"<div><div>The Qidashan iron deposit, which is the second-largest BIF-hosted high-grade iron deposit in the Anshan–Benxi areas, hosts chlorite-rich altered rocks and greisenized rocks that exhibit prominent Nb–Ta mineralization in proximity to high-grade iron ore bodies. This provides new clues to the ore-forming mechanism of BIF-hosted high-grade iron ore. In this study, we present new U–Pb dating results for columbite-group minerals (CGMs) from the altered rocks and granites in the Qidashan iron deposit, along with bulk major and trace element geochemical data from high-grade iron ores, BIFs, granites, chlorite-rich altered rocks, and greisenized rocks. The results indicate that the U–Pb dating of the CGMs yields similar ages among the Qidashan granite, chlorite-rich altered rocks, and greisenized rocks, suggesting a genetic linkage between the granite and the alteration processes. The geochemical features indicate that the altered rocks proximal to the high-grade iron ore bodies exhibit slight REE fractionation, moderate to strong negative Eu anomalies, higher contents of W, Sn, Cs and Rb, and lower contents of Ni than distal altered rocks do, indicating that the high-grade iron ores probably represent the ore-forming fluid pathways. In summary, a hydrosilicate fluid superimposition model was proposed, i.e., soon after the emplacement of the Qidashan granite, hydrosilicate fluids derived from the highly fractionated distal part of the granite migrated along various fractures and metasomatized the incipient granitic veins, BIFs, and their wall rocks, leading to the formation of greisenized rocks, high-grade iron ores, and chlorite-rich altered rock, respectively. These processes also facilitated the introduction of rare metal elements, such as Nb, Ta, Th, U, and LREEs, into both the altered rocks and high-grade iron ores. These findings highlight the potential for Nb–Ta mineralization in eastern Liaoning Province and provide new insights into the metallogenic evolution of high-grade iron ore in Qidashan deposit.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106791"},"PeriodicalIF":2.4,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096045","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":"Linkage, evolution and formation mechanism of the partially-thoroughgoing intra-cratonic conjugate strike-slip fault system in the northern Tarim Basin, NW China","authors":"Bingshan Ma ,&nbsp;Yang He ,&nbsp;Lixin Chen ,&nbsp;Guanghui Wu ,&nbsp;Hongqi Dong ,&nbsp;Jiamu Wang ,&nbsp;Jie Yao ,&nbsp;Xiaocen Liu","doi":"10.1016/j.jseaes.2025.106784","DOIUrl":"10.1016/j.jseaes.2025.106784","url":null,"abstract":"<div><div>The conjugate strike-slip fault displayed various types of fault architecture in the intersection zone under continuously updated physical technology, but the mechanism of conjugate strike-slip faults remains controversial. Herein we present typical geometries and throw of a conjugate strike-slip fault network to investigate the evolutionary process and mechanisms in the northern Tarim Basin, NW China. The results show that: (1) Linear, horsetail and intersection styles were proposed in the study area and the intersection styles showed asymmetry and partially-thoroughgoing fault characteristics; (2) Switch and migration of pure shear-simple shear mechanism from north to south jointly influenced the transition of fault geotrimies and differential intersection relationship and allocation of different stress mechanisms in N-S direction. (3) The differential intersection styles and their evolution were controlled by segment growth-linkage, disturbance and localization mechanisms, and restriction termination and branch cutting mechanisms from north to south, resulting in the partially thoroughgoing architecture. (4) The evolutionary process consists of an initial isolated stage, a subsequent linkage-intersection stage and a final disturbance-localization stage. The partially thoroughgoing strike-slip faults probably dominate the fault network in the intra-cratonic Tarim Basin, and even in other intra-cratonic basins.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106784"},"PeriodicalIF":2.4,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096042","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":"Cadmium enrichment and its significance in sphalerite from Baoshantao Pb-Zn deposit, Tongling district, Eastern China","authors":"Dayu Zhang ,&nbsp;Mengxiang Hu ,&nbsp;Zhongren Jiang ,&nbsp;Fei Zhang ,&nbsp;Hong Yi ,&nbsp;Huawei Yang ,&nbsp;Taofa Zhou","doi":"10.1016/j.jseaes.2025.106792","DOIUrl":"10.1016/j.jseaes.2025.106792","url":null,"abstract":"<div><div>The sphalerite has varying Cd concentrations in different types of Pb-Zn deposits, but the physicochemical factors that control its variability still needs more research. The Baoshantao is a newly discovered Pb-Zn polymetallic deposit in the Tongling ore district, Middle-Lower Yangtze River Metallogenic Belt (MYRB), China. In this study, geological and lithological observations were used to characterize the typical mineralized and altered samples, after which in-situ EPMA and LA-ICPMS analysis and mapping were carried on typical sphalerite grains. The petrographic characters suggest that Baoshantao is a Pb-Zn skarn deposit, and the sphalerite mineralization can be subdivided into three generations (Sp1, Sp2 and Sp3). EPMA and LA-ICPMS analytical results show that average Cd concentrations gradually decrease from Sp1 (5150 × 10^-6), Sp2 (3819 × 10^-6) to Sp3 (2424 × 10^-6); which occurring in the sphalerite by isomorphic substitution. The trace element characteristics refer that sphalerite in Baoshantao deposit formed at medium temperature (330 ℃ ∼ 207 ℃), medium sulfur fugacity, and less reduced environment. The Cd enrichment was through Cd²⁺=Fe²⁺ in the form of mass isomorphism. After compared with Pb-Zn deposits in the MYRB, reduced carbonate strata with high Cd abundance were favorable factors for Cd-rich sphalerite formation.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106792"},"PeriodicalIF":2.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158016","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":"Lithium mineralization processes associated magmatic-hydrothermal evolution in the Xiaohusite No.91 pegmatite, Altai, NW China: Insights from in situ chemical and boron isotope variations in tourmaline","authors":"Jian-Zheng Chen ,&nbsp;Yong Tang ,&nbsp;Hui Zhang ,&nbsp;Zheng-Hang Lv ,&nbsp;Jing-Yu Zhao ,&nbsp;Wen-Ting Huang ,&nbsp;Jing-Tao Wang","doi":"10.1016/j.jseaes.2025.106793","DOIUrl":"10.1016/j.jseaes.2025.106793","url":null,"abstract":"<div><div>The Xiaohusite No. 91 pegmatite in the Chinese Altai region is a pegmatite-type lithium deposit distinguished by prominent zonal textural features and multiple generations of tourmalines. The role of magmatic-hydrothermal evolution in zonation development associated with lithium mineralization processes remains a topic of debate. Tourmaline is a perfect probe for tracing magmatic-hydrothermal evolution, lithium mineralization processes and origins by comparative studying of mineral texture, chemical composition and boron isotope composition. From the outer to the inner zones, tourmalines varied from schorl to elbaite, within the content of Li showed positive correlation relation with Be, Nb, Ta, Mn, Ga, Pb, F contents and ^YAl/(^YAl + Fe) ratio, but negatively correlated with Mg, Fe, V and Zn contents, suggesting that fractional crystallization is the principal control on lithium mineralization in the studied pegmatite. The generally decreasing δ¹¹B values of tourmalines from the outer to inner zones are attributed to tourmaline crystallization, fluid exsolution and temperature decreasing. The occurrence of zoned tourmalines with Li-rich and lower δ¹¹B value rims indicates the fluid exsolution during the magmatic-hydrothermal transition stage promoted lithium mineralization. Furthermore, based on the overall boron isotopic composition (δ¹¹B =  − 15.3 to − 13.6 ‰) of the tourmalines, partial melting of a Li-rich metasedimentary source is inferred to be a prerequisite for lithium mineralization.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"294 ","pages":"Article 106793"},"PeriodicalIF":2.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096039","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":"Chlorite and associated influence on reservoir properties in tight sandstones of the Upper Shaximiao Formation, SW Sichuan Basin, China","authors":"Yunbiao Zhao ,&nbsp;Fan Huang ,&nbsp;Zhenghui Chen ,&nbsp;Zhi Zhao ,&nbsp;Hong Yu ,&nbsp;Ze Liu ,&nbsp;Chenhui Zhao","doi":"10.1016/j.jseaes.2025.106794","DOIUrl":"10.1016/j.jseaes.2025.106794","url":null,"abstract":"<div><div>Authigenic chlorite is widely distributed in tight sandstone reservoirs of the Upper Shaximiao Formation in the southwestern Sichuan Basin. Understanding its genesis and impact on reservoir quality is crucial for natural gas exploration. This study systematically investigated the occurrence, formation mechanisms, and effects of authigenic chlorite on the reservoir quality. Three morphotypes were identified: grain-coating, pore-lining (dominant type), and pore-filling. Compositional analysis revealed that grain-coating chlorite was primarily Mg-chlorite, while pore-lining and pore-filling types were composed of either Mg- or Al-chlorite. Authigenic chlorite formed at medium to low temperatures and low oxygen/sulfur fugacity. Grain-coating chlorite originated during the syndiagenesis to eodiagenesis A stage and formed via adsorptive precipitation of chlorite precursors on detrital grain surfaces under high-energy hydrodynamic conditions or through the transformation of montmorillonite. Pore-lining chlorite developed during the eodiagenesis B stage, with Fe²⁺ and Mg²⁺ sourced from the decomposition of biotite and mafic rock fragments. Pore-filling chlorite formed in the late mesodiagenesis A stage, sharing similar sources with pore-lining chlorite while also exhibiting direct illite transformation pathways. Authigenic chlorite has dual effects on reservoir properties. Grain-coating chlorite and thin, continuous pore-lining chlorite enhance sandstone strength and inhibit secondary quartz growth, whereas thick pore-lining chlorite and pore-filling chlorite reduce porosity and permeability by occupying pore spaces. This study elucidates the relationship between authigenic chlorite formation and reservoir evolution, offering a scientific basis for predicting “sweet spots” in tight sandstone reservoirs of the Upper Shaximiao Formation.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"293 ","pages":"Article 106794"},"PeriodicalIF":2.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145048355","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}