Journal of Asian Earth Sciences最新文献

{"title":"Decarbonated eclogite in the mantle sources of the Wajilitag mafic-ultramafic intrusion, Permian Tarim Large Igneous Province, NW China: Evidence from Zn isotopes","authors":"Shengkai Jin ,&nbsp;Zhenchao Wang ,&nbsp;Hengxu Li ,&nbsp;Linghan Liu","doi":"10.1016/j.jseaes.2025.106710","DOIUrl":"10.1016/j.jseaes.2025.106710","url":null,"abstract":"<div><div>The formation of the Tarim Large Igneous Province (TLIP) has been linked to oceanic crust subduction, yet the specific interactions between the subducting crust and the TLIP mantle source remain ambiguous. Zn isotopes, a newly developed stable isotope system, offer promising potential for identifying recycled carbonates within the mantle. Here, a detailed analysis of Zn isotopes in the Wajilitag Fe-Ti oxide-bearing mafic–ultramafic intrusion of the TLIP is presented. The observed δ⁶⁶Zn values (0.27 ‰ ± 0.03 ‰ to 0.48 ‰ ± 0.02 ‰) are heavier than those found in Mid-Ocean Ridge Basalts (MORBs; 0.24 ‰ to 0.31 ‰), potentially indicating the influence of the incorporation of recycled sedimentary carbonates into the mantle source. However, the subalkaline nature and depleted ⁸⁷Sr/⁸⁶Sr compositions of the Wajilitag mafic–ultramafic intrusion suggest that sedimentary carbonate incorporation into the mantle occurs via decarbonation. During these processes, Zn from the carbonates (dolomite and magnesite) is transferred to silicates (diopside and enstatite) with accompanying isotope exchange, resulting in the residual silicates inheriting and preserving the heavy Zn isotope signatures. Together with detailed petrographic observations, Rhyolite-MELTS simulations and MATLAB lsqr () function for quaternary mixing calculations, it is concluded that, variations in Zn isotopes among the intrusion lithofacies are primarily driven by differing degrees of Fe-Ti oxides and olivine accumulation. Additionally, our study highlights the potential role of recycled sedimentary carbonates in deep carbon cycling through decarbonation reactions.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106710"},"PeriodicalIF":2.7,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144308140","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":"Reducing environment and enhanced productivity controlled the accumulation of organic matter in the Upper Yangtze Basin, South China during the Late Ordovician-Early Silurian","authors":"Yan-Jun Bao ,&nbsp;Yuan-Yuan Sun ,&nbsp;Di Zhang ,&nbsp;Jian-Fei Yan ,&nbsp;Yu-Peng Men ,&nbsp;Wei Sun ,&nbsp;Jia-Shan Lin ,&nbsp;You-Li Wan ,&nbsp;Jian-Wei Kang ,&nbsp;Wen-Hua Wang ,&nbsp;Qiangba Zhaxi","doi":"10.1016/j.jseaes.2025.106694","DOIUrl":"10.1016/j.jseaes.2025.106694","url":null,"abstract":"<div><div>The Upper Yangtze Basin developed a set of widespread organic-rich shales during the period from the Late Ordovician to the Early Silurian. The mechanisms controlling the accumulation of organic matter are the subject of much controversy. In the present study, we used various geochemical data, including total organic matter content, mineral composition, and trace and major elements from Well Daoye 1 drilled in the northern Guizhou Province, to evaluate the factors controlling the accumulation of organic matter. The indices such as CIA, Al%, Ti%, U/Th, V/Cr, Ni/Co, U-EF, V-EF, Mo-EF, Cu_xs, Ni_xs, Excess Si, C-vaule, Cu/Al, Ni/Al, Co <span><math><mrow><mo>×</mo></mrow></math></span> Mn, Zr/Cr and Zr/Al₂O₃ were calculated from these data to reconstruct the paleoclimate, terrigenous influx, seawater redox conditions, and paleoproductivity. Pyrite framboid size statistics were used as an additional proxy in this study to differentiate redox conditions between the anoxic state of the water column and the water/sediment interface. The results obtained from this study suggest that both the strongly reducing environment of the water column and the enhanced paleoproductivity played key roles in the widespread accumulation of organic matter. We found that the importance of these two factors in controlling the accumulation of organic matter varies under different circumstances through the Ordovician-Silurian transition in the Upper Yangtze Basin. Our study invites a case-by-case investigation when evaluating the controlling factors of organic matter accumulation in different settings.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106694"},"PeriodicalIF":2.7,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279419","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":"Indium distribution in sulfides from a Sn-poor skarn system: A case study of the Lawu Cu–Pb–Zn deposit, Tibet","authors":"Jiadai Li ,&nbsp;Jing Xu ,&nbsp;Taiping Zhao ,&nbsp;Suyu Chen","doi":"10.1016/j.jseaes.2025.106703","DOIUrl":"10.1016/j.jseaes.2025.106703","url":null,"abstract":"<div><div>The Lawu Cu–Pb–Zn deposit is situated in the eastern part of Nyainqêntanglha metallogenic belt, Tibet. It represents a rare indium (In)-bearing and tin (Sn)-poor skarn system, however, the occurrence, distribution, and endowment of In, along with their geochemical controls, remain poorly constrained. In this contribution, we conducted a comprehensive mineralogical study of sulfides using microscopic observation, electron probe micro-analyzer (EPMA), and laser ablation inductively coupled plasma mass spectrometer (LA–ICP–MS). Based on mineral assemblage and textural relationships, four types of sphalerite are identified: sphalerite I as micro-inclusions within chalcopyrite and pyrrhotite, sphalerite II with abundant mineral inclusions, sphalerite III exhibiting chalcopyrite disease with watermelon texture, and sphalerite IV displaying a relatively clean texture with minimal inclusions. Sphalerite I is enriched in In, Cu, Cd, and Mn, whereas sphalerite II and sphalerite IV exhibit variable contents of In, Sn, Cu, Mn, Co, Se, and Ag. Trace elements, such as In, commonly occur in sulfides via isomorphic substitution, with minor amounts present as micron-scale mineral inclusions (e.g., Cu in sphalerite; Pb and Bi in sphalerite, chalcopyrite, and pyrite). From the perspective of In content in minerals, In is mainly hosted in sphalerite (average &gt;400 ppm). Chalcopyrite also shows relatively elevated In content (average ∼200 ppm). Pyrrhotite, pyrite, and arsenopyrite typically contain negligible In content, generally below 10 ppm. According to the GGIMFis geothermometer calculations, the crystallization temperatures of sphalerite II to sphalerite IV are as follows: 378 to 427 °C (average = 398 °C) for sphalerite II, 389 to 399 °C (395 °C) for sphalerite III, and 338 to 375 °C (356 °C) for sphalerite IV. The In, Cu, and Co contents in sphalerite increase with crystallization temperatures, implying that their incorporation is primarily controlled by the temperature of ore-forming fluids. Combined with the published sphalerite dataset, a strong correlation is inferred between In and Sn, Cu, or Fe. Notably, Sn-poor Zn-polymetallic skarn systems represent strategic targets for In resource exploration. This finding refines the understanding of In occurrence and enrichment in Sn-poor skarn systems, providing insights applicable to similar geological environments.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106703"},"PeriodicalIF":2.7,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279421","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":"Distribution and enrichment of scandium in minerals of the Bayan Obo REE-Nb-Fe deposit, Inner Mongolia, north China","authors":"Zhi-Shuang Yang ,&nbsp;Xiao-Wen Huang ,&nbsp;Yu-Miao Meng","doi":"10.1016/j.jseaes.2025.106705","DOIUrl":"10.1016/j.jseaes.2025.106705","url":null,"abstract":"<div><div>Scandium is a critical metal, and its mineralization mechanisms have attracted widespread attention. The Bayan Obo REE-Nb-Fe deposit in northern China is one of the most important Sc resources. However, the distribution and enrichment of Sc in minerals remain poorly understood. This study systematically investigates the Sc contents in over 20 minerals using laser ablation ICP-MS. Results show that columbite (average Sc: 9100 ppm), samarskite (2200 ppm), aegirine [NaFe³⁺(Si₂O₆)] (1250 ppm), and zircon (350 ppm) are significant host minerals for Sc. Scandium is variably enriched in hematite, diopside, and riebeckite [Na₂(Mg, Fe)₃Fe²⁺(Si₈O₂₂)(OH)₂], with contents ranging from 20 to 200 ppm. The other 17 minerals, including aeschynite, fergusonite, dolomite, albite, fersmite, magnetite, pyrrhotite, ilmenite, monazite, rhodochrosite, parisite, rutile, barite, apatite, calcite, pyrite, and cordylite, have average Sc contents below 20 ppm. Scandium can be incorporated into aegirine via Sc³⁺ + Al³⁺ ↔ Mg²⁺ + Ti⁴⁺ and into riebeckite via Sc³⁺ + Mg²⁺ ↔ Al³⁺ + Fe²⁺. The Sc-rich rim and Sc-depleted core in aegirine indicate heterogeneous Sc distribution, likely caused by dissolution-reprecipitation processes. Contrasting enrichment patterns of Sc and REE in aegirine are due to various F/Cl ratios in fluids. Scandium preferentially incorporates into mafic silicate minerals due to its similar ionic radius to those of Fe and Mg. Oxidation of magnetite to hematite cannot lead to Sc enrichment. Elevated Sc in studied hematite suggests a direct precipitation from Sc-bearing fluids rather than a transformation from magnetite.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106705"},"PeriodicalIF":2.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254493","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":"Hydrothermal mobility of In, Sn, Cu, Cd, Fe, Pb, Zn during interactions between HF- and HCl-bearing fluids and granitic melts: experimental constraints on In mineralization","authors":"Jian Di ,&nbsp;Xing Ding ,&nbsp;Xiaolong Huang ,&nbsp;Taiping Zhao","doi":"10.1016/j.jseaes.2025.106706","DOIUrl":"10.1016/j.jseaes.2025.106706","url":null,"abstract":"<div><div>Abundant indium (In) is frequently observed as an impurity element within sphalerite and closely associated with granite-related Sn-polymetallic deposits. Magmatic-hydrothermal processes have been proposed to govern In mineralization; however, the underlying mechanisms remain poorly understood. This study experimentally investigates geochemical behaviors of In, Sn, Cu, Cd, Fe, Pb, and Zn during interactions between granitic melts and 0.5–2.0 mol/L HF-bearing or 0.5–11.0 mol/L HCl-bearing solutions at 850 ℃ and 200 MPa. The results reveal a significant covariation relationship between In and these elements. Specifically, In, Sn, Zn, Cu, and Cd were enriched in all granitic melts, with their concentrations progressively increasing with higher HF concentrations but decreasing with higher HCl concentrations in both melts and solutions, while Fe and Pb were roughly depleted. This distinction is attributed to the low hydrothermal mobility of In, Sn, Zn, Cu, and Cd, which promotes their synchronous enrichment within acidic magmatic-hydrothermal systems. The results also highlight a strong pH dependence on hydrothermal mobility of In. Acidic F- or Cl-bearing fluids can enrich In within the granitic melts by a factor of 5 to 20 or 1 to 10 times, respectively. In contrast, neutral-alkaline Cl-bearing fluids may cause substantial depletion of In by factors of up to 1000 times. Consequently, the exsolution of acidic F- or Cl-bearing fluids could be an essential prerequisite for generating an In-rich magma reservoir. Subsequent activities involving neutral-alkaline fluids, such as exotic brine extraction or saline fluid exsolution, can efficiently transport In from the In-rich magmas into hydrothermal fluids, thereby facilitating In mineralization.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106706"},"PeriodicalIF":2.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254494","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":"Constraints of in situ chemical compositions and Rb-Sr age of biotite on hydrothermal overprinting in the Bayan Obo REE-Nb-Fe deposit, Inner Mongolia, North China","authors":"Yong Xu ,&nbsp;Xiao-Wen Huang ,&nbsp;Fei-Lin Zhu ,&nbsp;Yu-Miao Meng","doi":"10.1016/j.jseaes.2025.106704","DOIUrl":"10.1016/j.jseaes.2025.106704","url":null,"abstract":"<div><div>The Bayan Obo REE-Nb-Fe deposit in Northern China is famous for its large reserves of critical metals such as REE and Nb. Previous studies about ore genesis mainly focused on the timing and origin of primary REE and Nb mineralization. However, the timing of deformation and hydrothermal overprinting on different types of primary mineralization was not well constrained. Biotite slate is one of significant wall rocks and has been hydrothermally altered and mineralized. The biotite slate is composed of biotite and calcite, with minor pyrite, magnetite/hematite, ilmenite, and bastnäsite. Biotite exhibits curved bands and is partially replaced by chlorite and muscovite, indicative of post-crystallization ductile deformation and fluid-induced alteration. Biotite belongs to the Mg-rich variety with the crystallization temperatures of 672 °C to 773 °C. It was possibly originally magmatic in origin and was modified by hydrothermal fluids. Biotite has relatively low REE and high Nb and F contents, probably reflecting modification by Nb-F-rich hydrothermal fluids or Nb and F enrichment inherited from magmatic biotite. <em>In situ</em> Rb-Sr dating of biotite from two samples yields Rb-Sr isochron ages of 310 ± 11 Ma and 309.4 ± 9.3 Ma, respectively. Biotite has initial ⁸⁷Sr/⁸⁶Sr ratios between 0.7011 and 0.7054, similar to those of mantle reservoirs. Together with previous dating results, our study provides constraints on the Hercynian hydrothermal activity which likely contributed to Nb mineralization.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106704"},"PeriodicalIF":2.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144264094","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 mafic to intermediate rocks within the crustal sequence of the Luqu ophiolite in the Yarlung-Tsangpo suture Zone, southern Tibet and implications for the Neo-Tethys evolution","authors":"Chang Zhang ,&nbsp;Chuan-Zhou Liu ,&nbsp;Tong Liu ,&nbsp;Wen-Bin Ji ,&nbsp;Zhen-Yu Zhang ,&nbsp;Fu-Yuan Wu","doi":"10.1016/j.jseaes.2025.106696","DOIUrl":"10.1016/j.jseaes.2025.106696","url":null,"abstract":"<div><div>Ophiolites provide insights into the lithosphere of vanished oceans and serve as key archives for reconstructing their evolutionary histories. In southern Tibet, ophiolites exposed within the Yarlung-Tsangpo Suture Zone are interpreted as remnants of the Cretaceous Neo-Tethyan lithosphere. However, origin and source characteristics of these lithospheric remnants remain controversial. This study presents new geochemical data from crustal rocks (dolerites, basalts, and leugogabbros) within the Luqu section of the Xigaze ophiolites. The northern Luqu section preserves intact crustal sequence dominated by doleritic dykes, sill complexes, and massive to pillowed lavas. Notably, minor leucogabbro intrusions within the dolerites were identified. Geochemical analyses reveal that the dolerites and basalts exhibit flat to moderately depleted LREE patterns, consistent with derivation from a depleted mantle source. The leucogabbros yield crystallization ages (132 – 125 Ma) overlapping with those of the mafic dolerites (∼125 Ma) and other YTSZ crustal sequences (134 – 120 Ma). Mineralogically, they contain high-Mg# clinopyroxene, high-An plagioclase, and amphibole, suggesting hydrous parental melts. The leucogabbro display distinct isotopic compositions — unradiogenic Sr-Hf coupled with enriched Nd. Petrological and geochemical evidence indicates these leucogabbros originated via partial melting of lower crustal gabbros, with contributions from enriched components within their sources. Gabbro solidus was likely lowered by infiltration of seawater-derived hydrothermal fluids, a process facilitated by detachment faults in ultraslow-spreading settings. These faults enable seawater penetration, enhancing fluid-rock interaction and melt hybridization. Our findings suggest that mafic rocks and leucogabbros in the Xigaze ophiolites were sourced from distinct mantle domains within an ultraslow-spreading ridge.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106696"},"PeriodicalIF":2.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240797","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":"Reconstructing the tectonic evolution of the Mudanjiang Ocean: Metamorphic insights from the Heilongjiang Complex, NE China","authors":"Guang-Ming Sun ,&nbsp;Xu-Ping Li ,&nbsp;Hans-Peter Schertl ,&nbsp;Jin-Rui Zhang ,&nbsp;Xiao Wang ,&nbsp;Wen-Yong Duan","doi":"10.1016/j.jseaes.2025.106695","DOIUrl":"10.1016/j.jseaes.2025.106695","url":null,"abstract":"<div><div>The Heilongjiang Complex in northeast China marks the suture zone recording the closure of the Mudanjiang Ocean between the Jiamusi and Songliao blocks. This study presents the first integrated analysis of garnet amphibolite, epidote-barroisite schist, and garnet-staurolite-mica schist from this complex, combining petrology, mineral chemistry, thermodynamic modelling, whole-rock geochemistry, and geochronology to constrain their metamorphic evolution and protolith origins. The garnet amphibolites display a peak mineral assemblage of garnet + amphibole + clinopyroxene + plagioclase + sphene + quartz, corresponding to pressure–temperature (P–T) conditions of 10.9–13.1 kbar and 712–760 °C. These conditions indicate an intermediate geothermal gradient, reflecting high-temperature metamorphism associated with early warm subduction of basaltic oceanic crust. E-MORB-like geochemical signatures and zircon U–Pb ages suggest a middle Permian oceanic crust protolith (ca. 272 Ma), with subsequent amphibolite-facies metamorphism occurring around 235 Ma. The epidote-barroisite schists are characterized by a peak assemblage of sodium amphibole + epidote + chlorite + phengite + sphene + rutile + quartz, and record peak P–T conditions of 14.9–16.4 kbar and 472–505 °C. These values correspond to a low geothermal gradient of 9–11 °C/km, consistent with mature, cold subduction environments. Their OIB-like geochemical affinities and zircon ages of 244–241 Ma indicate a basaltic seamount origin within the Mudanjiang Ocean during the middle Triassic. The garnet-staurolite-mica schists record a clockwise P–T path, marked by decompression coupled with heating from blueschist- to amphibolite-facies conditions. This thermal evolution supports a diapiric exhumation model into the warm middle to lower crust of the overriding plate, rather than exhumation along a cold subduction channel, and is interpreted as a response to the collision between the Jiamusi and Songliao blocks. Integrating these findings with previous research, we propose a revised tectonic model for the Mudanjiang Ocean. Its initial opening occurred in a back-arc extensional setting in the western Jiamusi Block, driven by westward subduction of the Mongol–Okhotsk Ocean during the latest Carboniferous to Permian. Final closure and continental amalgamation took place during the late Triassic to middle Jurassic, resulting from westward subduction and compression of the Paleo-Pacific Plate. The Mudanjiang Ocean is interpreted as a branch of the Panthalassa or Paleo-Pacific Ocean, with an estimated lifespan of approximately 116 million years, spanning from the early Permian to middle Jurassic (ca. 288–172 Ma).</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106695"},"PeriodicalIF":2.7,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240800","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":"Unveiling tectonic activity through lithological-erosional interplay with the Τectonic Processes Index Tδ","authors":"Dimitrios Ntokos","doi":"10.1016/j.jseaes.2025.106680","DOIUrl":"10.1016/j.jseaes.2025.106680","url":null,"abstract":"<div><div>Identifying regions susceptible to earthquakes is crucial for mitigating seismic hazards. This study introduces the Tectonic Processes Index (<em>T_δ</em>), a novel morphotectonic index that integrates lithology (<em>δ</em>) to enhance the assessment of tectonic activity and seismic hazards. Traditional indices such as the Hypsometric Integral (<em>HI</em>) can be limited in areas dominated by erodible lithologies. While <em>HI</em> accounts for both tectonic and erosional influences, it often fails to fully capture basin evolution under complex geological conditions. <em>T_δ</em> addresses this limitation by explicitly incorporating the interaction between tectonic forces, erosional patterns, and lithological variability. This comprehensive approach offers a more detailed understanding of basin development and its tectonic significance. Application in northwestern Greece—a region with diverse geological settings—demonstrates the <em>T_δ</em>’s effectiveness. The validity of <em>T_δ</em> is further supported through comparative analysis with mapped tectonic structures, seismicity records, and conventional morphotectonic indices, confirming its robustness in capturing active tectonic processes. <em>T_δ</em> reliably distinguishes quiescent basins from those affected by neotectonic deformation. Compared to traditional methods, it offers improved resolution in identifying tectonically active areas. Beyond seismic hazard assessment, <em>T_δ</em> has the potential to inform land-use planning and support geological resource management in seismically sensitive regions.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106680"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240801","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":"Thermodynamic simulation on indium enrichment condition in the Huangshaping skarn Zn-Pb system (South China)","authors":"Yihan Wu ,&nbsp;Yi Zheng ,&nbsp;Pengpeng Yu ,&nbsp;Yin Huang ,&nbsp;Jie Yu ,&nbsp;Taiping Zhao ,&nbsp;Qiuming Cheng ,&nbsp;Xi Chen","doi":"10.1016/j.jseaes.2025.106681","DOIUrl":"10.1016/j.jseaes.2025.106681","url":null,"abstract":"<div><div>Indium, crucial for emerging industries like optoelectronics, is a strategic metal linked to national prosperity and defense. However, understanding its enrichment during migration-precipitation in skarn-type Zn-Pb deposits is limited. This study focuses on the Huangshaping Zn-Pb deposit in the Nanling belt, China, which is a skarn-type deposit with quartz porphyry as the ore-causative intrusion. Through petrography, mineralization was identified as skarn, oxide, and sulfide stages, with three sphalerite types (Sp1, Sp2a, Sp2b). EPMA and LA-ICP-MS analyses revealed different indium concentrations, with Sp1 being the most enriched (mean = 134.54 ppm). LA-ICP-MS mapping showed that Sp1 is rich in In, Cu, and Sn. Mineral paragenesis combined with GGIMFis thermometer for sphalerite trace elements and thermodynamic calculations indicate indium-rich sphalerite precipitates under weakly acidic pH 4.5–6.0, high oxygen fugacity (logfO₂ = –32.2 to −29.7), high temperature (201–316 °C), and high sulfur fugacity (logfS₂ = −13.42 to −7.11) in a reduced, H₂S-rich environment. We propose that in skarn systems, the enrichment of indium occurs during the early stages of sphalerite crystallization, specifically at high temperatures. This enrichment process occurs in a fluid environment characterized by a weakly acidic pH, high oxygen fugacity, and high sulfur fugacity. The findings deepen our understanding on indium enrichment and the physicochemical conditions in skarn-type Zn-Pb systems and may aid prospecting in similar deposits.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"291 ","pages":"Article 106681"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240796","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}