Pub Date : 2026-02-15Epub Date: 2025-11-29DOI: 10.1016/j.jseaes.2025.106894
Junyi Wang , Guotao Sun , Jia-Xi Zhou , Hui Chen , Bing Yu , Kai Luo , Shiyu Liu , Ruiliang Wang
Indium is a critical metal that can be concentrated in skarn deposits. However, not all skarn deposits exhibit indium mineralization. The controlling factors of indium mineralization in skarn deposits are unclear. We investigate the sphalerite trace element, geological setting, geochemical compositions of related intrusions, and hydrothermal physicochemical conditions of 47 skarn deposits worldwide to unravel the critical factors for indium mineralization. The deposits are classified into four types according to the indium content in sphalerite. The In-rich skarn deposits are predominantly distributed in the intra-continental extension setting. The In-rich skarn deposits show higher SiO2 values and Rb/δEu ratios, and lower MgO contents than the In-poor deposits, indicating that the evolution process evaluates the indium enrichment in magma. The Sr-Nd-Hf isotopes suggest that In-rich skarns are almost or partly derived from the partial melting of metasedimentary rocks; however, In-poor deposits are dominantly derived from the melting of the mafic lower crust. The similar hydrothermal temperatures (200 to 300 °C), salinities (4 to 12 NaCl wt%), and δ34S (–5 to 10 ‰) between In-rich and In-poor deposits imply that the indium contents in sphalerite may be irrelevant to these conditions. The In and Cu contents define a solubility limit (CIn=CCu), indicating that the Cu activity controls the maximum indium contents in sphalerite. The study highlights that the skarn-related indium mineralization is a coupled consequence of the magma sources, evolution, and hydrothermal Cu activity.
{"title":"Skarn-related sphalerite: Indium enrichment and key controlling factors","authors":"Junyi Wang , Guotao Sun , Jia-Xi Zhou , Hui Chen , Bing Yu , Kai Luo , Shiyu Liu , Ruiliang Wang","doi":"10.1016/j.jseaes.2025.106894","DOIUrl":"10.1016/j.jseaes.2025.106894","url":null,"abstract":"<div><div>Indium is a critical metal that can be concentrated in skarn deposits. However, not all skarn deposits exhibit indium mineralization. The controlling factors of indium mineralization in skarn deposits are unclear. We investigate the sphalerite trace element, geological setting, geochemical compositions of related intrusions, and hydrothermal physicochemical conditions of 47 skarn deposits worldwide to unravel the critical factors for indium mineralization. The deposits are classified into four types according to the indium content in sphalerite. The In-rich skarn deposits are predominantly distributed in the intra-continental extension setting. The In-rich skarn deposits show higher SiO<sub>2</sub> values and Rb/δEu ratios, and lower MgO contents than the In-poor deposits, indicating that the evolution process evaluates the indium enrichment in magma. The Sr-Nd-Hf isotopes suggest that In-rich skarns are almost or partly derived from the partial melting of metasedimentary rocks; however, In-poor deposits are dominantly derived from the melting of the mafic lower crust. The similar hydrothermal temperatures (200 to 300 °C), salinities (4 to 12 NaCl wt%), and δ<sup>34</sup>S (–5 to 10 ‰) between In-rich and In-poor deposits imply that the indium contents in sphalerite may be irrelevant to these conditions. The In and Cu contents define a solubility limit (<em>C</em><sub>In</sub>=<em>C</em><sub>Cu</sub>), indicating that the Cu activity controls the maximum indium contents in sphalerite. The study highlights that the skarn-related indium mineralization is a coupled consequence of the magma sources, evolution, and hydrothermal Cu activity.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"297 ","pages":"Article 106894"},"PeriodicalIF":2.4,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694600","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}
Pub Date : 2026-01-01Epub Date: 2025-11-26DOI: 10.1016/j.jseaes.2025.106881
Qinglong Chen , Xin Cheng , Nan Jiang , Bitian Wei , Dongmeng Zhang , Longyun Xing , Yanan Zhou , Teng Li , Ruiyang Chai , Hanning Wu
The Jurassic-Cretaceous closure dynamics of the Bangong-Nujiang Tethyan Ocean provide pivotal constraints on the Tibetan Plateau’s collisional orogeny and crustal thickening. To rigorously constrain the subduction and closure processes of the Bangong-Nujiang Tethyan Ocean during the Jurassic-Cretaceous, this study employs systematic anisotropy of magnetic susceptibility (AMS) analysis. By investigating the relationship between the maximum principal compressive stress direction (inferred from magnetic of susceptibility ellipsoids) and the subduction dynamics of the Bangong-Nujiang Tethyan, we establish new structural deformation insights from the continuous Middle Jurassic-Late Cretaceous sedimentary sequences in the Linzhou Basin of the Lhasa Block. These findings provide critical constraints on the Jurassic-Cretaceous subduction evolution of the Bangong-Nujiang Tethyan Ocean. The Linzhou Basin, spanning from the Middle Jurassic Yeba Fm. to the Late Cretaceous Shexing Fm., experienced dual subduction dynamics: southward subduction of the Bangong-Nujiang Tethyan Ocean and northward subduction of the Yarlung-Zangbo Neo-Tethys Ocean. Crucially, the AMS data reveal that underlying strata preserved their primary deformation signatures without being overprinted by younger tectonic events. This implies that the AMS record faithfully reflects the contemporaneous tectonic stress field during the deposition and early deformation of each stratigraphic horizon. During the Middle-Late Jurassic, the Shiquanhe-Namco Ocean remained an open oceanic domain until its eventual closure in the Early Cretaceous. Consequently, the southward compressional stress regime documented in the Linzhou Basin during this interval likely reflects a composite tectonic signature, originating from the dual south subduction systems of both the Bangong-Nujiang Tethys Ocean and the Shiquanhe-Namco Ocean. Until the Early Cretaceous Takena Fm., the southward compression experienced by the Linzhou Basin was only related to the southward subduction of the Bangong- Nujiang Tethys Ocean. The Bangong-Nujiang Tethyan Ocean did not close during the Late Cretaceous Shexing Fm., but the subduction intensity was significantly reduced compared to the Early Cretaceous Takena Fm., indicating that the Bangong-Nujiang Tethyan Ocean tended to close.
{"title":"Middle Jurassic to Late Cretaceous tectonic evolution of the southern Lhasa Block, Tibet, China: Constraints from anisotropy of magnetic susceptibility (AMS) of the Linzhou Baisn","authors":"Qinglong Chen , Xin Cheng , Nan Jiang , Bitian Wei , Dongmeng Zhang , Longyun Xing , Yanan Zhou , Teng Li , Ruiyang Chai , Hanning Wu","doi":"10.1016/j.jseaes.2025.106881","DOIUrl":"10.1016/j.jseaes.2025.106881","url":null,"abstract":"<div><div>The Jurassic-Cretaceous closure dynamics of the Bangong-Nujiang Tethyan Ocean provide pivotal constraints on the Tibetan Plateau’s collisional orogeny and crustal thickening. To rigorously constrain the subduction and closure processes of the Bangong-Nujiang Tethyan Ocean during the Jurassic-Cretaceous, this study employs systematic anisotropy of magnetic susceptibility (AMS) analysis. By investigating the relationship between the maximum principal compressive stress direction (inferred from magnetic of susceptibility ellipsoids) and the subduction dynamics of the Bangong-Nujiang Tethyan, we establish new structural deformation insights from the continuous Middle Jurassic-Late Cretaceous sedimentary sequences in the Linzhou Basin of the Lhasa Block. These findings provide critical constraints on the Jurassic-Cretaceous subduction evolution of the Bangong-Nujiang Tethyan Ocean. The Linzhou Basin, spanning from the Middle Jurassic Yeba Fm. to the Late Cretaceous Shexing Fm., experienced dual subduction dynamics: southward subduction of the Bangong-Nujiang Tethyan Ocean and northward subduction of the Yarlung-Zangbo Neo-Tethys Ocean. Crucially, the AMS data reveal that underlying strata preserved their primary deformation signatures without being overprinted by younger tectonic events. This implies that the AMS record faithfully reflects the contemporaneous tectonic stress field during the deposition and early deformation of each stratigraphic horizon. During the Middle-Late Jurassic, the Shiquanhe-Namco Ocean remained an open oceanic domain until its eventual closure in the Early Cretaceous. Consequently, the southward compressional stress regime documented in the Linzhou Basin during this interval likely reflects a composite tectonic signature, originating from the dual south subduction systems of both the Bangong-Nujiang Tethys Ocean and the Shiquanhe-Namco Ocean. Until the Early Cretaceous Takena Fm., the southward compression experienced by the Linzhou Basin was only related to the southward subduction of the Bangong- Nujiang Tethys Ocean. The Bangong-Nujiang Tethyan Ocean did not close during the Late Cretaceous Shexing Fm., but the subduction intensity was significantly reduced compared to the Early Cretaceous Takena Fm., indicating that the Bangong-Nujiang Tethyan Ocean tended to close.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"296 ","pages":"Article 106881"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685357","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}
Pub Date : 2026-01-01Epub Date: 2025-09-30DOI: 10.1016/j.jseaes.2025.106802
Shivani Hulaji , Venkatraman S Hegde , Xian Hua Li , V.N. Vasudev , Li Su , Asim Ranjan Pratihari , Manjunath Paltekar
Dharwar Craton in South India, offers important insights into the crustal evolution history of the Neoarchaean. This study investigates the tectonic evolution of granitoids adjacent to the central part of the Hungund greenstone belt, northernmost part of the Eastern Dharwar craton through a multidisciplinary approach involving field investigation, petrographic studies, whole rock geochemistry along with zircon mineral chemistry and U-Pb zircon ages of biotite granites and sanukitoids. The biotite granite from eastern parts of the belt are 2595–2607 Ma, show peraluminous to metaluminous characteristics; Mg# ranging from 17 to 30 with a distinct negative Eu/Eu* of 0.06–0.33, high Rb/Sr (avg. 3.96) and low Sr/Y (avg. 5.50) ratios suggesting their generation by partial melting of tonalite-trondhjemite granodiorite (TTG) in the continental margin arc settings. Trace element compositions of zircons from the dated granites corroborate their continental crustal-derived magma in arc setting. The sanukitoids, on the other hand, are metaluminous, with comparatively higher Mg# (28–40), mild Eu/Eu*0.36–0.59, low Rb/Sr (avg. 0.22) and high Sr/Y (avg. 47.31) ratios originated from a mix of crustal and mantle derived components. In view of differences in their geochemical characteristics, mode of origin and ages, they are considered to have a distinct petrogenetic and tectonic history, amalgamated during accretionary event. Integration of the present work with the data from various continents reveal that cratonic evolution through amalgamation of microcrustal block was a global phenomenon during the Neoarchaean.
{"title":"2.6 Ga granitoids in the Eastern Dharwar Craton: amalgamation of micro-crustal blocks and cratonization in the Neoarchaean","authors":"Shivani Hulaji , Venkatraman S Hegde , Xian Hua Li , V.N. Vasudev , Li Su , Asim Ranjan Pratihari , Manjunath Paltekar","doi":"10.1016/j.jseaes.2025.106802","DOIUrl":"10.1016/j.jseaes.2025.106802","url":null,"abstract":"<div><div>Dharwar Craton in South India, offers important insights into the crustal evolution history of the Neoarchaean. This study investigates the tectonic evolution of granitoids adjacent to the central part of the Hungund greenstone belt, northernmost part of the Eastern Dharwar craton through a multidisciplinary approach involving field investigation, petrographic studies, whole rock geochemistry along with zircon mineral chemistry and U-Pb zircon ages of biotite granites and sanukitoids. The biotite granite from eastern parts of the belt are 2595–2607 Ma, show peraluminous to metaluminous characteristics; Mg# ranging from 17 to 30 with a distinct negative Eu/Eu* of 0.06–0.33, high Rb/Sr (avg. 3.96) and low Sr/Y (avg. 5.50) ratios suggesting their generation by partial melting of tonalite-trondhjemite granodiorite (TTG) in the continental margin arc settings. Trace element compositions of zircons from the dated granites corroborate their continental crustal-derived magma in arc setting. The sanukitoids, on the other hand, are metaluminous, with comparatively higher Mg# (28–40), mild Eu/Eu*0.36–0.59, low Rb/Sr (avg. 0.22) and high Sr/Y (avg. 47.31) ratios originated from a mix of crustal and mantle derived components. In view of differences in their geochemical characteristics, mode of origin and ages, they are considered to have a distinct petrogenetic and tectonic history, amalgamated during accretionary event. Integration of the present work with the data from various continents reveal that cratonic evolution through amalgamation of microcrustal block was a global phenomenon during the Neoarchaean.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106802"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418283","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}
Pub Date : 2026-01-01Epub Date: 2025-10-13DOI: 10.1016/j.jseaes.2025.106832
Chao Yang , Shu Zhang , Xiang Qian , Tong Hou , Song-Song Zhang , Ming-An Wu , Guo-Hui Wei
The newly discovered Xiangshannan-Dadiantang iron oxide-apatite (IOA) deposit provides critical insights into the spatiotemporal and genetic linkages between magma evolution and IOA mineralization in the Ningwu Basin. High-precision zircon U-Pb geochronology constrains the intrusion of ore-related subvolcanic diorite porphyries to 129.76 ± 0.98 Ma and 129.49 ± 0.87 Ma, contemporaneous with the Dawangshan Formation trachyandesite (129.78 ± 0.98 Ma) and post ore syenite porphyry (128.49 ± 0.57 Ma), aligning with regional metallogenic climax at ∼ 130 Ma. Integrated geochemical and multi-isotope (Sr-Nd-Hf) data indicate that the trachyandesites and mineralized diorite porphyries originated from a shared metasomatized mantle reservoir, as evidenced by overlapping εHf(t) values (−7.60 to − 3.71, mean = − 6.12; −7.16 to − 2.57, mean = − 4.20) and distinct εNd(t) ranges (−7.24 to − 7.31 and − 4.70 to − 4.93), with isotopic signatures reflecting crustal assimilation. Petrological analyzing demonstrates that medium-pressure differentiation (1.0–1.3 GPa) involving olivine-clinopyroxene fractionation preserved high MgO (>4 wt%), suppressing premature magnetite saturation. Crucially, Triassic evaporite assimilation triggered sulfate reduction, elevating oxygen fugacity, which optimized magnetite supersaturation concurrent with exsolution of ultrahigh-salinity brines. The presence of inherited Triassic zircons (225–250 Ma) in trachyandesite and diorite porphyry reveals that the rising magma assimilated Triassic evaporites, incorporating oxidizing agents and halogens vital for the subsequent iron mineralization. This study establishes a threefold genetic framework: (1) moderate-pressure differentiation preserving Fe-rich melts, (2) evaporite-driven oxidation optimizing magnetite stability, and (3) early brine exsolution enabling iron transport—elucidating the unique metallogenic signature of the Dawangshan subvolcanic phase in the Ningwu district.
{"title":"Petrogenesis of the diorite porphyry in the Xiangshannan-Dadiantang iron oxide-apatite deposit, Ningwu Basin, Eastern China: implications for iron mineralization","authors":"Chao Yang , Shu Zhang , Xiang Qian , Tong Hou , Song-Song Zhang , Ming-An Wu , Guo-Hui Wei","doi":"10.1016/j.jseaes.2025.106832","DOIUrl":"10.1016/j.jseaes.2025.106832","url":null,"abstract":"<div><div>The newly discovered Xiangshannan-Dadiantang iron oxide-apatite (IOA) deposit provides critical insights into the spatiotemporal and genetic linkages between magma evolution and IOA mineralization in the Ningwu Basin. High-precision zircon U-Pb geochronology constrains the intrusion of ore-related subvolcanic diorite porphyries to 129.76 ± 0.98 Ma and 129.49 ± 0.87 Ma, contemporaneous with the Dawangshan Formation trachyandesite (129.78 ± 0.98 Ma) and post ore syenite porphyry (128.49 ± 0.57 Ma), aligning with regional metallogenic climax at ∼ 130 Ma. Integrated geochemical and multi-isotope (Sr-Nd-Hf) data indicate that the trachyandesites and mineralized diorite porphyries originated from a shared metasomatized mantle reservoir, as evidenced by overlapping ε<sub>Hf</sub>(t) values (−7.60 to − 3.71, mean = − 6.12; −7.16 to − 2.57, mean = − 4.20) and distinct ε<sub>Nd</sub>(t) ranges (−7.24 to − 7.31 and − 4.70 to − 4.93), with isotopic signatures reflecting crustal assimilation. Petrological analyzing demonstrates that medium-pressure differentiation (1.0–1.3 GPa) involving olivine-clinopyroxene fractionation preserved high MgO (>4 wt%), suppressing premature magnetite saturation. Crucially, Triassic evaporite assimilation triggered sulfate reduction, elevating oxygen fugacity, which optimized magnetite supersaturation concurrent with exsolution of ultrahigh-salinity brines. The presence of inherited Triassic zircons (225–250 Ma) in trachyandesite and diorite porphyry reveals that the rising magma assimilated Triassic evaporites, incorporating oxidizing agents and halogens vital for the subsequent iron mineralization. This study establishes a threefold genetic framework: (1) moderate-pressure differentiation preserving Fe-rich melts, (2) evaporite-driven oxidation optimizing magnetite stability, and (3) early brine exsolution enabling iron transport—elucidating the unique metallogenic signature of the Dawangshan subvolcanic phase in the Ningwu district.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106832"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364930","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}
Pub Date : 2026-01-01Epub Date: 2025-10-28DOI: 10.1016/j.jseaes.2025.106848
Xiao-Wen Huang , Xin-Fu Zhao , Xiaochun Li
Hydrothermal Fe deposits, including skarn Fe, iron oxide-apatite (IOA), and iron oxide-copper–gold (IOCG), are major global sources of Fe ores. Beyond their well-established economic value for Fe, these deposits are increasingly recognized as significant reservoirs of critical metals such as Co, Ga, Ge, Sc, and rare earth elements (REE). With the growing demand for these metals, driven by high-tech industries and the green energy sector, a more comprehensive understanding of their occurrence and enrichment processes within hydrothermal Fe systems is essential. While previous studies have predominantly focused on the genesis of the Fe mineralization, studies dedicated to the distribution and enrichment mechanisms of associated critical metals remain limited.
{"title":"Hydrothermal Fe deposits and associated critical metals","authors":"Xiao-Wen Huang , Xin-Fu Zhao , Xiaochun Li","doi":"10.1016/j.jseaes.2025.106848","DOIUrl":"10.1016/j.jseaes.2025.106848","url":null,"abstract":"<div><div>Hydrothermal Fe deposits, including skarn Fe, iron oxide-apatite (IOA), and iron oxide-copper–gold (IOCG), are major global sources of Fe ores. Beyond their well-established economic value for Fe, these deposits are increasingly recognized as significant reservoirs of critical metals such as Co, Ga, Ge, Sc, and rare earth elements (REE). With the growing demand for these metals, driven by high-tech industries and the green energy sector, a more comprehensive understanding of their occurrence and enrichment processes within hydrothermal Fe systems is essential. While previous studies have predominantly focused on the genesis of the Fe mineralization, studies dedicated to the distribution and enrichment mechanisms of associated critical metals remain limited.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106848"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418282","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}
Pub Date : 2026-01-01Epub Date: 2025-11-04DOI: 10.1016/j.jseaes.2025.106855
Chenglong Li , Xuefen Sheng , Rui Bao , Jiawei Da
Geochemical proxies of carbonates are widely applied in Quaternary paleoclimate reconstructions. However, differences in formation processes among secondary carbonate types can yield divergent environmental signals, making their reconstructions not directly comparable. Here, we compare the δ13C and δ18O values of two types of secondary carbonates from the Mangshan loess-paleosol section on the southeastern margin of the Chinese Loess Plateau: non-biogenic carbonates (bulk, clay-sized samples and nodules) and biogenic carbonates (fossil land snail shells), to evaluate their consistency and identify the causes of discrepancies. Fossil snail shells exhibit only minor aragonite-to-calcite transformation (average calcite content 5.4%), whereas non-biogenic carbonates consist of secondary calcite without detrital dolomite. The δ13C values of land snail shells vary from −6.87 ‰ to −1.59 ‰, lower than those of bulk samples (from −3.57 ‰ to −1.51 ‰), clay-sized samples (from −5.12 ‰ to −1.27 ‰), and nodules (from −3.46 ‰ to −1.56 ‰). These isotopic offsets are also observed in modern samples and other sections, mainly reflecting differences in plant types recorded by the two carbonate types, along with a minor contribution from atmospheric CO2. By contrast, the δ18O values of shells (−9.61 ‰ to −2.83 ‰) are higher than those of bulk samples (−9.88 ‰ to −8.77 ‰), clay-sized samples (−10.34 ‰ to −7.61 ‰), and nodules (−9.92 ‰ to −9.10 ‰). This suggests that stronger evaporative enrichment occurred in surface soil water for snail shell formation, compared with subsurface soil water involved in pedogenic carbonate formation. Overall, the geochemical differences between biogenic and non-biogenic carbonates arise from distinct formation processes; therefore, using those geochemical proxies for paleoclimate reconstruction needs caution.
{"title":"δ13C and δ18O differences between biogenic and non-biogenic carbonates in Chinese loess-paleosol sections: Implications for paleoclimate proxies","authors":"Chenglong Li , Xuefen Sheng , Rui Bao , Jiawei Da","doi":"10.1016/j.jseaes.2025.106855","DOIUrl":"10.1016/j.jseaes.2025.106855","url":null,"abstract":"<div><div>Geochemical proxies of carbonates are widely applied in Quaternary paleoclimate reconstructions. However, differences in formation processes among secondary carbonate types can yield divergent environmental signals, making their reconstructions not directly comparable. Here, we compare the δ<sup>13</sup>C and δ<sup>18</sup>O values of two types of secondary carbonates from the Mangshan loess-paleosol section on the southeastern margin of the Chinese Loess Plateau: non-biogenic carbonates (bulk, clay-sized samples and nodules) and biogenic carbonates (fossil land snail shells), to evaluate their consistency and identify the causes of discrepancies. Fossil snail shells exhibit only minor aragonite-to-calcite transformation (average calcite content 5.4%), whereas non-biogenic carbonates consist of secondary calcite without detrital dolomite. The δ<sup>13</sup>C values of land snail shells vary from −6.87 ‰ to −1.59 ‰, lower than those of bulk samples (from −3.57 ‰ to −1.51 ‰), clay-sized samples (from −5.12 ‰ to −1.27 ‰), and nodules (from −3.46 ‰ to −1.56 ‰). These isotopic offsets are also observed in modern samples and other sections, mainly reflecting differences in plant types recorded by the two carbonate types, along with a minor contribution from atmospheric CO<sub>2</sub>. By contrast, the δ<sup>18</sup>O values of shells (−9.61 ‰ to −2.83 ‰) are higher than those of bulk samples (−9.88 ‰ to −8.77 ‰), clay-sized samples (−10.34 ‰ to −7.61 ‰), and nodules (−9.92 ‰ to −9.10 ‰). This suggests that stronger evaporative enrichment occurred in surface soil water for snail shell formation, compared with subsurface soil water involved in pedogenic carbonate formation. Overall, the geochemical differences between biogenic and non-biogenic carbonates arise from distinct formation processes; therefore, using those geochemical proxies for paleoclimate reconstruction needs caution.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106855"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466992","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}
Pub Date : 2026-01-01Epub Date: 2025-10-21DOI: 10.1016/j.jseaes.2025.106834
Maxim Rudmin , Edward J. Matheson , Alexey Ruban
This study focuses on reconstructing the paleoenvironmental conditions responsible for the formation of Upper Cretaceous and Paleogene ooidal ironstones in Western Siberia, using detailed analyses of the Bakchar deposit. Two clastic and four chemical lithofacies are identified in the deposit. Morphometric parameters calculated based on an analysis of the authigenic and detrital fractions of ironstones and host rocks are used to determine the degree of undisturbed (autochthonous) or disturbed/re-transported (parautochthonous) chemical sediments. Spatial changes in sedimentation from the coastline are expressed by replacing chemical lithofacies with clastic lithofacies or by transitioning medium- and fine-grained sandstone lithofacies into sandy-clay deposits. Chemical lithofacies consist predominantly of iron-rich ooids, peloids and/or glauconite pellets with different types of cement. They are not laterally equivalent to one another, but each represents a distinct lithological type of ironstones formed at different times in the basin. Textural features of ooidal ironstones combined with assessment of the authigenic and detrital fractions make it possible to distinguish depositional hiatuses and intervals of autochthonous ooid deposition (autochthonous ooid interval). The Bakchar succession contains seven main autochthonous ooid intervals in the following times: Middle Santonian, Late Santonian, Middle Campanian, Campanian-Maastrichtian boundary, Middle Maastrichtian, Late Maastrichtian, and Paleocene-Eocene boundary. Autochthonous ooid intervals are usually transited up section by intraclast-rich ironstone layers with depositional hiatuses. Potential sources of detrital fraction were identified based on the detrital assemblages and the detrital zircon age. The weathering of Permian-Triassic intrusive rocks of the Tom-Kolyvan and the Salair folded systems is assumed to be a source of detrital minerals for the Santonian layers. Meanwhile, for the Maastrichtian and Paleocene successions, an additional part of the material was inputted from the intrusive Paleozoic formations of the Kuznetsk Alatau. Fingerprints of post-sedimentation (burial diagenetic) influences on ironstones are the presence of veinlet siderite cement, associations of siderite cement with pyrrhotite or wurtzite, and injections of ooids into each other. The lithofacies and structural characteristics of the ooid fraction (autochthonous ooid intervals), the mineral assemblages and the chemical composition of the ironstones testify to the repeated supply of ore-forming hydrothermal solutions to the basin of the Bakchar deposit. Fluid mobilisation events coincide with ironstone layers with an autochthonous ooid fraction, which are often overlain by layers with depositional hiatuses, expressed in an increase in the proportion of parautochthonous items of sedimentary rocks.
{"title":"Sedimentation and formation of Late Cretaceous and Paleogene ironstones in ancient epicontinental West Siberian Sea","authors":"Maxim Rudmin , Edward J. Matheson , Alexey Ruban","doi":"10.1016/j.jseaes.2025.106834","DOIUrl":"10.1016/j.jseaes.2025.106834","url":null,"abstract":"<div><div>This study focuses on reconstructing the paleoenvironmental conditions responsible for the formation of Upper Cretaceous and Paleogene ooidal ironstones in Western Siberia, using detailed analyses of the Bakchar deposit. Two clastic and four chemical lithofacies are identified in the deposit. Morphometric parameters calculated based on an analysis of the authigenic and detrital fractions of ironstones and host rocks are used to determine the degree of undisturbed (autochthonous) or disturbed/re-transported (parautochthonous) chemical sediments. Spatial changes in sedimentation from the coastline are expressed by replacing chemical lithofacies with clastic lithofacies or by transitioning medium- and fine-grained sandstone lithofacies into sandy-clay deposits. Chemical lithofacies consist predominantly of iron-rich ooids, peloids and/or glauconite pellets with different types of cement. They are not laterally equivalent to one another, but each represents a distinct lithological type of ironstones formed at different times in the basin. Textural features of ooidal ironstones combined with assessment of the authigenic and detrital fractions make it possible to distinguish depositional hiatuses and intervals of autochthonous ooid deposition (autochthonous ooid interval). The Bakchar succession contains seven main autochthonous ooid intervals in the following times: Middle Santonian, Late Santonian, Middle Campanian, Campanian-Maastrichtian boundary, Middle Maastrichtian, Late Maastrichtian, and Paleocene-Eocene boundary. Autochthonous ooid intervals are usually transited up section by intraclast-rich ironstone layers with depositional hiatuses. Potential sources of detrital fraction were identified based on the detrital assemblages and the detrital zircon age. The weathering of Permian-Triassic intrusive rocks of the Tom-Kolyvan and the Salair folded systems is assumed to be a source of detrital minerals for the Santonian layers. Meanwhile, for the Maastrichtian and Paleocene successions, an additional part of the material was inputted from the intrusive Paleozoic formations of the Kuznetsk Alatau. Fingerprints of post-sedimentation (burial diagenetic) influences on ironstones are the presence of veinlet siderite cement, associations of siderite cement with pyrrhotite or wurtzite, and injections of ooids into each other. The lithofacies and structural characteristics of the ooid fraction (autochthonous ooid intervals), the mineral assemblages and the chemical composition of the ironstones testify to the repeated supply of ore-forming hydrothermal solutions to the basin of the Bakchar deposit. Fluid mobilisation events coincide with ironstone layers with an autochthonous ooid fraction, which are often overlain by layers with depositional hiatuses, expressed in an increase in the proportion of parautochthonous items of sedimentary rocks.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106834"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145365041","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}
Pub Date : 2026-01-01Epub Date: 2025-11-03DOI: 10.1016/j.jseaes.2025.106852
Amir Esna-Ashari , Jamshid Hassanzadeh , Antonio Langone , Fatemeh Sarjoughian , Massimo Tiepolo
The origin of Nb-rich basalts—specifically high-Nb basalts (HNB) and Nb-enriched basalts (NEB)—is a key issue in subduction-related igneous petrology. The gabbroic rocks from the Alvand Plutonic Complex (ALPC) in the Neo-Tethyan Sanandaj-Sirjan Zone of Iran, with zircon U–Pb crystallization ages of 165 ± 2 Ma, provide a valuable natural setting for investigating these magmas. The trace element chemistry of gabbroic clinopyroxene and amphibole indicates crystallization from a parental melt with similarities with both HNB and OIB-type alkaline magmas. Major and trace element data show that the clinopyroxene compositions lie between those of OIB-like melts and highly depleted ultramafic boninitic rocks (HDUR) found in the same plutonic belt. Similarly, bulk-rock gabbros that are the intrusive equivalent of basalts span a compositional range from HNB to NEB and are transitional between OIB and HDUR end-members.
We propose that the ALPC gabbros formed by mixing between an OIB-type magma, sourced from upwelling asthenosphere through a slab window, and a highly depleted boninitic melt sourced from partial melting of a depleted mantle wedge. This mixing model contrasts with the widely accepted adakitic model, which involves melting of a mantle wedge previously metasomatized by slab-derived melts. Our findings highlight the overlooked role of boninitic magmas in generating Nb-rich basalts and suggest that variable proportions of OIB and boninitic components can produce the compositional spectrum observed in HNB and NEB worldwide.
{"title":"Can Nb-enriched arc basalts result from mixing of boninite and ocean island basalt magmas? A case study from Jurassic gabbroic rocks of western Iran (Sanandaj-Sirjan Zone)","authors":"Amir Esna-Ashari , Jamshid Hassanzadeh , Antonio Langone , Fatemeh Sarjoughian , Massimo Tiepolo","doi":"10.1016/j.jseaes.2025.106852","DOIUrl":"10.1016/j.jseaes.2025.106852","url":null,"abstract":"<div><div>The origin of Nb-rich basalts—specifically high-Nb basalts (HNB) and Nb-enriched basalts (NEB)—is a key issue in subduction-related igneous petrology. The gabbroic rocks from the Alvand Plutonic Complex (ALPC) in the Neo-Tethyan Sanandaj-Sirjan Zone of Iran, with zircon U–Pb crystallization ages of 165 ± 2 Ma, provide a valuable natural setting for investigating these magmas. The trace element chemistry of gabbroic clinopyroxene and amphibole indicates crystallization from a parental melt with similarities with both HNB and OIB-type alkaline magmas. Major and trace element data show that the clinopyroxene compositions lie between those of OIB-like melts and highly depleted ultramafic boninitic rocks (HDUR) found in the same plutonic belt. Similarly, bulk-rock gabbros that are the intrusive equivalent of basalts span a compositional range from HNB to NEB and are transitional between OIB and HDUR end-members.</div><div>We propose that the ALPC gabbros formed by mixing between an OIB-type magma, sourced from upwelling asthenosphere through a slab window, and a highly depleted boninitic melt sourced from partial melting of a depleted mantle wedge. This mixing model contrasts with the widely accepted adakitic model, which involves melting of a mantle wedge previously metasomatized by slab-derived melts. Our findings highlight the overlooked role of boninitic magmas in generating Nb-rich basalts and suggest that variable proportions of OIB and boninitic components can produce the compositional spectrum observed in HNB and NEB worldwide.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106852"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520823","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}
Pub Date : 2026-01-01Epub Date: 2025-10-14DOI: 10.1016/j.jseaes.2025.106831
Alastair H.F. Robertson , Osman Parlak , Havva Soycan , Kemal Taslı
The SW segment of the Antalya Complex (Antalya nappes) documents sedimentation, magmatism and tectonics related to Permian-Triassic continental rifting, Jurassic-Cretaceous passive margin subsidence, Late Cretaceous ophiolite genesis, and latest Cretaceous initial emplacement. Pulsed rifting took place during Late Permian and Early Triassic, followed by continental break-up during Late Triassic, and then Jurassic-Late Cretaceous (Santonian) passive margin subsidence. In the west, the Lower Antalya Unit records Late Triassic (Norian) rifting and collapse of the adjacent carbonate platform (Bey Dağları), then latest Triassic (Rhaetian)-Cenomanian development of a channelised carbonate slope with redeposited shallow-water carbonates. The Middle Antalya Unit begins with Mid-Triassic (Ladinian) radiolarites, overlain by Middle-Upper Triassic siliciclastic turbidites, deep-water hemipelagic carbonates (drift deposits) and radiolarites. Alkaline volcanics erupted during Late Triassic in a deep-water setting. Deep-water radiolarites characterised Rhaetian to Late Cenomanian-Turonian. Within the Upper Antalya Unit farther east, above pre-rift and early syn-rift crust, Middle Triassic (Ladinian) radiolarites were followed by Upper Triassic hemipelagic carbonates, then uppermost Triassic-Cenomanian shallow-water platform carbonates. The SW Antalya Complex restores to the northern margin of the Southern Neotethys. The upper unit (Cambrian-Devonian) rifted during Late Permian, Middle Triassic (Ladinian) and Late Triassic (Carnian-Norian). Rift-related flexural and/or thermal uplift preceded seafloor spreading, similar to the Central-Northern Red Sea. Dismembered ophiolitic rocks were emplaced from the adjacent Southern Neotethys during the latest Cretaceous. Initial ophiolite emplacement resulted in collapse of the passive margin and transgression by mass-flow deposits. Initial emplacement by thrusting and strike-slip, during late Campanian-Maastrichtian, was followed by Paleocene, Eocene and Miocene emplacement events.
{"title":"Triassic-Cretaceous sedimentary and magmatic development of the classic SW outcrop of the Antalya Complex, S Türkiye as a developing rift and passive margin bordering the Southern Neotethys","authors":"Alastair H.F. Robertson , Osman Parlak , Havva Soycan , Kemal Taslı","doi":"10.1016/j.jseaes.2025.106831","DOIUrl":"10.1016/j.jseaes.2025.106831","url":null,"abstract":"<div><div>The SW segment of the Antalya Complex (Antalya nappes) documents sedimentation, magmatism and tectonics related to Permian-Triassic continental rifting, Jurassic-Cretaceous passive margin subsidence, Late Cretaceous ophiolite genesis, and latest Cretaceous initial emplacement. Pulsed rifting took place during Late Permian and Early Triassic, followed by continental break-up during Late Triassic, and then Jurassic-Late Cretaceous (Santonian) passive margin subsidence. In the west, the Lower Antalya Unit records Late Triassic (Norian) rifting and collapse of the adjacent carbonate platform (Bey Dağları), then latest Triassic (Rhaetian)-Cenomanian development of a channelised carbonate slope with redeposited shallow-water carbonates. The Middle Antalya Unit begins with Mid-Triassic (Ladinian) radiolarites, overlain by Middle-Upper Triassic siliciclastic turbidites, deep-water hemipelagic carbonates (drift deposits) and radiolarites. Alkaline volcanics erupted during Late Triassic in a deep-water setting. Deep-water radiolarites characterised Rhaetian to Late Cenomanian-Turonian. Within the Upper Antalya Unit farther east, above pre-rift and early syn-rift crust, Middle Triassic (Ladinian) radiolarites were followed by Upper Triassic hemipelagic carbonates, then uppermost Triassic-Cenomanian shallow-water platform carbonates. The SW Antalya Complex restores to the northern margin of the Southern Neotethys. The upper unit (Cambrian-Devonian) rifted during Late Permian, Middle Triassic (Ladinian) and Late Triassic (Carnian-Norian). Rift-related flexural and/or thermal uplift preceded seafloor spreading, similar to the Central-Northern Red Sea. Dismembered ophiolitic rocks were emplaced from the adjacent Southern Neotethys during the latest Cretaceous. Initial ophiolite emplacement resulted in collapse of the passive margin and transgression by mass-flow deposits. Initial emplacement by thrusting and strike-slip, during late Campanian-Maastrichtian, was followed by Paleocene, Eocene and Miocene emplacement events.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106831"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579683","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}
Mafic microgranular enclaves (MMEs) are typically considered products of magma mixing, preserving distinct physicochemical signatures relative to their host rocks. In this study, we investigate the Late Cretaceous Huanggang MME-bearing granite pluton in the southern Great Xing’an Range (SRXR) and demonstrate that MMEs share similar crystallization physicochemical conditions with the host granites. Integrated crystallization temperature and pressure calculations, based on in-situ mineral compositions (zircon, apatite, hornblende, and feldspar), reveal overlapping thermal (620–700 °C) and pressure (0.05–0.53 GPa) conditions. Despite these similarities, MMEs exhibit higher oxygen fugacity (ΔFMQ = − 0.75 to + 4.84) and water activity (H2Omelt = 3.1–3.8 wt%) compared to host granites (ΔFMQ = − 0.45 to + 2.30, H2Omelt = 2.9–3.3 wt%). These variations suggest MMEs formed under more oxidizing and hydrous melt conditions. Apatite geochemistry shows pronounced fluorine enrichment, with F/Cl ratios (19.2–92.6) and F concentrations (2.56–2.92 wt%) indicating a fluorine-rich source, likely from slab dehydration in subduction zones. While thermobarometric conditions suggest a genetic relationship between MMEs and host granites, differences in redox-sensitive element ratios imply distinct melt evolution pathways. We propose that MMEs formed either from localized mixed melts during the late-stage homogenization of the magma chamber or from the early crystallization of post-mixed melt. This study highlights that MMEs can form both during active melt interaction and subsequent crystallization processes. The subduction of the Paleo-Pacific plate serves as the geodynamic driver for magma mixing in the SGXR, which is also linked to the Early Cretaceous polymetallic metallogenies in this region.
{"title":"Magma mixing and Mantle-Crust evolution during the early Cretaceous: Insights from the mineral geochemistry of Huanggang MME-bearing granite in the southern Great Xing’an Range, NE China","authors":"Jiangpeng Shi , Guang Wu , Gongzheng Chen , Yanjing Chen","doi":"10.1016/j.jseaes.2025.106844","DOIUrl":"10.1016/j.jseaes.2025.106844","url":null,"abstract":"<div><div>Mafic microgranular enclaves (MMEs) are typically considered products of magma mixing, preserving distinct physicochemical signatures relative to their host rocks. In this study, we investigate the Late Cretaceous Huanggang MME-bearing granite pluton in the southern Great Xing’an Range (SRXR) and demonstrate that MMEs share similar crystallization physicochemical conditions with the host granites. Integrated crystallization temperature and pressure calculations, based on <em>in</em>-<em>situ</em> mineral compositions (zircon, apatite, hornblende, and feldspar), reveal overlapping thermal (620–700 °C) and pressure (0.05–0.53 GPa) conditions. Despite these similarities, MMEs exhibit higher oxygen fugacity (ΔFMQ = − 0.75 to + 4.84) and water activity (H<sub>2</sub>O<sub>melt</sub> = 3.1–3.8 wt%) compared to host granites (ΔFMQ = − 0.45 to + 2.30, H<sub>2</sub>O<sub>melt</sub> = 2.9–3.3 wt%). These variations suggest MMEs formed under more oxidizing and hydrous melt conditions. Apatite geochemistry shows pronounced fluorine enrichment, with F/Cl ratios (19.2–92.6) and F concentrations (2.56–2.92 wt%) indicating a fluorine-rich source, likely from slab dehydration in subduction zones. While thermobarometric conditions suggest a genetic relationship between MMEs and host granites, differences in redox-sensitive element ratios imply distinct melt evolution pathways. We propose that MMEs formed either from localized mixed melts during the late-stage homogenization of the magma chamber or from the early crystallization of post-mixed melt. This study highlights that MMEs can form both during active melt interaction and subsequent crystallization processes. The subduction of the Paleo-Pacific plate serves as the geodynamic driver for magma mixing in the SGXR, which is also linked to the Early Cretaceous polymetallic metallogenies in this region.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"295 ","pages":"Article 106844"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466993","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}
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