Geoscience frontiers最新文献

{"title":"Sustainable development at the crossroads: Geopolitical risks, natural resource scarcity, and renewable energy in energy security transitions","authors":"Jinjun Zhang ,&nbsp;Liu Xiao-feng","doi":"10.1016/j.gsf.2025.102129","DOIUrl":"10.1016/j.gsf.2025.102129","url":null,"abstract":"<div><div>Energy security is a crucial aspect of modern societies, as it directly impacts the availability, accessibility, and reliability of energy sources. The reliance on natural resources and geopolitical factors in shaping energy security has gained significant attention in recent years. Natural resources and geopolitical risk are examined in 38 countries at risk of geopolitical conflict between 1990 and 2021 by examining CO₂ emissions, renewable energy consumption, and foreign direct investment as controlling variables. The long-run analysis conducted in this study focused on slope heterogeneity, Westerlund cointegration, and dynamic panel data estimation. The findings indicated that the energy security index is positively associated with various determinants, including natural resources, geopolitical risk, CO₂ emissions, and renewable energy consumption. However, foreign direct investment was found to be negatively associated with the energy security index among the selected 38 geopolitical risk countries. The role of natural resources and geopolitical risk in energy security cannot be overlooked. Natural resources provide the raw materials for generating electricity and powering our societies, while geopolitical risks can disrupt energy supply chains and threaten stability. Achieving sustainable energy security requires a comprehensive approach that addresses both aspects of energy provision. Transitioning to renewable energy sources, improving energy efficiency, diversifying energy supplies, promoting international cooperation, and conserving natural resources are essential steps towards a more sustainable and resilient energy future.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102129"},"PeriodicalIF":8.9,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144887017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disentangling relative controls of landscape evolution and spatial heterogeneity in the Vaigai River Basin, southern India: Regional implications and applicability","authors":"K.J. Juni ,&nbsp;M. Ramkumar ,&nbsp;B. Venkateshwaran ,&nbsp;D. Menier ,&nbsp;M.J. Mathew ,&nbsp;K. Balasubramani ,&nbsp;N.A. Siddiqui","doi":"10.1016/j.gsf.2025.102128","DOIUrl":"10.1016/j.gsf.2025.102128","url":null,"abstract":"<div><div>Deciphering tectono-climatic-lithological and other controls over landscape evolution at variable spatiotemporal scales is paramount in natural resources management and development. We have systematically documented and analysed selected critical quantitative morphometric data, namely, asymmetry factor, hypsometric integral, hypsometric curve, drainage divide migration and normalised steepness index, in addition to the assessment of longitudinal profiles and knickpoints, for a unique morphological river basin, the Vaigai River Basin, located in southern India. The spatial variability of various controls of geomorphological characteristics of the basin is interpreted using these morphometric parameters and field data. Notable results include, predominance of a concave-up nature of the majority of the sub-basins, occurrence of a distinct convex zone in the upper part and a distinctly concave zone in the lower part of the basin, a range of symmetric to asymmetric topographic nature with very prominent asymmetry in the middle of the basin, highest normalised channel steepness in the northernmost sub-basin and insignificant and lesser steepness in the majority of the basin, evidence of north-easterly migration of drainage divides within the river basin, manifested by sub-basin boundaries and the alignment of the majority of the knickpoints parallel to the NE–SW trending Karur-Kambam-Painavu-Thrissur shear zone. The results cumulatively indicate that the Vaigai River that runs on an antecedent basin continues evolving, principally under the controls of regional Precambrian structures. Nevertheless, the evolution has been episodic and spatially varied. The resurgent tectonic influence is more pronounced in the northern and north-western parts of the basin, while the river capture and drainage divide migration are pronounced in the northeastern part, signifying the collective influence of tectonics and climate. On the contrary, the middle and lower reaches of the basin lack a soil-sediment-weathered zone, signifying the prevalence of an intense erosional phase of the river. This information, together with previously documented catastrophic flooding events and sediment accumulation, categorise the river basin as episodically active, and in a transient phase of evolution. While providing affirmative evidence for the previous regional geomorphological model, the interpretation of the continuum of inherited Precambrian structures in the present study implies that there are subtle spatial differences of lithological-climatological and structural controls within and among each of the sub-basins that need to be considered for any natural resources management at local to regional scales.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 6","pages":"Article 102128"},"PeriodicalIF":8.9,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geologic methane emissions from the Daginsky thermo-mineral springs in the northeast of Sakhalin Island: 2024 expedition and remote sensing data","authors":"Nadezhda Syrbu ,&nbsp;Andrei Kholmogorov ,&nbsp;Aleksey Legkodimov ,&nbsp;Igor Stepochkin ,&nbsp;Rafael Zharkov ,&nbsp;Anatoly Salyuk ,&nbsp;Vyacheslav Kantalin","doi":"10.1016/j.gsf.2025.102127","DOIUrl":"10.1016/j.gsf.2025.102127","url":null,"abstract":"<div><div>The paper deals with the urgent problem of gas-geochemical parameters in the seas and shelf transit zones based on a comparison of field studies and remote sensing data. The results of complex gas-geochemical studies of the Daginsky gas-hydrothermal system are presented, as well as an assessment of methane emissions from the studied area. The Daginsky gas-hydrothermal system is located on the northeastern coast of Sakhalin Island, and is a unique object due to a combination of a number of factors: from zonality due to the proximity of the Okhotsk Sea and the geological structure, to the interaction of deep and surface processes manifested in the presence of biogenic and thermogenic methane, as well as mantle helium. Tectonic faults and oil and gas bearing structures of the northeastern shelf of Sakhalin, which determine the direction of natural gas flows and facilitate its migration to the surface, make a significant contribution to the gas appearance of thermal springs. The main gas is methane up to 90%, homologues of methane up to and including pentane have been established, and isolated high concentrations of helium and hydrogen, both dissolved and in the free gas of bubbles, have also been noted. The conducted isotope studies allow to speak about the complex genesis of the gas. <em>δ</em>¹³C isotopic composition, ranging from −49.4‰ to −60.2‰ shows the dominance of biogenic methane with an admixture of thermogenic component. This is also confirmed by the presence of a fraction of mantle helium. The flow of methane into the atmosphere from the Daginsky area is 963757.5 mol/(km²·day), or about 15.4 t/(km²·year), which indicates the importance of this region for the regional and global carbon cycle. The dynamics of methane emissions can vary depending on various factors, such as seasonal fluctuations and geological activity, which further complicates the understanding of processes in the region.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102127"},"PeriodicalIF":8.9,"publicationDate":"2025-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable carbon isotope compositions of individual light hydrocarbons in oils: New indicator of source facies and maturity","authors":"Donglin Zhang ,&nbsp;Meijun Li ,&nbsp;Rongzhen Qiao","doi":"10.1016/j.gsf.2025.102126","DOIUrl":"10.1016/j.gsf.2025.102126","url":null,"abstract":"<div><div>Light hydrocarbons (LHs) are key components of petroleum, and the carbon isotopes composition (<em>δ</em>¹³C) of individual LHs contains a wealth of geochemical information. Forty-four oil samples from five different basins were analyzed using gas chromatography (GC), gas chromatography-mass spectrometry (GC–MS), and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The <em>δ</em>¹³C values of forty-three LHs were recognized and determined by comparing the GC and GC-IRMS methods. The results revealed significant differences in <em>δ</em>¹³C distribution characteristics among different LH compounds. The <em>δ</em>¹³C variation of individual LHs in <em>iso-</em>paraffins showed the widest range, followed by cycloalkanes and aromatics, whereas the <em>δ</em>¹³C variation in <em>n</em>-paraffins showed the narrowest range. The <em>δ</em>¹³C values of most individual LHs are primarily affected by the source facies and thermal evolution. Among them, c-1, 3-dimethylcyclohexane (c-1, 3DMCH) is mainly sourced from higher plants but may also form through abiotic mechanisms such as catalysis or cyclization. The <em>δ</em>¹³C values of c-1, 3DMCH (<em>δ</em>¹³C_{c-1, 3DMCH}) primarily exhibit parental genetic characteristics, enabling effective distinction of oil from different source facies. Specifically, the <em>δ</em>¹³C_{c-1, 3DMCH} in marine oils, lacustrine oils, terrigenous oils, and coal-formed oils are &lt; –22‰, from –22‰ to −20.2‰, from −20.2‰ to −18.4‰, and &gt; −18.4‰, respectively. Moreover, maturity is the primary controlling factor for <em>δ</em>¹³C values of 3MC₇ (<em>δ</em>¹³C_3MC7, 3MC₇: 3-methylheptane), while the source facies serve as a secondary influence. The plot of <em>δ</em>¹³C_{c-1, 3DMCH} and <em>δ</em>¹³C_3MC7 was introduced to classify source facies. As <em>δ</em>¹³C_{c-1, 3DMCH} and <em>δ</em>¹³C_3MC7 increase, the source facies transits from marine to lacustrine, then terrigenous, and finally coal facies. Additionally, increasing <em>δ</em>¹³C_3MC7 indicates a relative increase in maturity. Therefore, the <em>δ</em>¹³C_{c-1, 3DMCH} vs. <em>δ</em>¹³C_3MC7 plot serves as an effective tool for distinguishing source facies and assessing relative maturity.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102126"},"PeriodicalIF":8.9,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arc magma evolution: Insights from magnesium and iron isotope in mafic–ultramafic rocks, Eastern Kunlun, NW China","authors":"Zhixiong Zhao ,&nbsp;Guochen Dong ,&nbsp;Shan Ke ,&nbsp;Dicheng Zhu","doi":"10.1016/j.gsf.2025.102125","DOIUrl":"10.1016/j.gsf.2025.102125","url":null,"abstract":"<div><div>The origin of magnesium and iron isotope variations in mafic–ultramafic rocks has long been debated. In particular, a substantial lack of understanding exists regarding how the variation in the Mg and Fe isotopic compositions of arc magmas relates to fractional crystallization. Here, we report new Mg and Fe isotopic analyses of mafic–ultramafic rocks formed by co-genetic magmatic evolution in the Eastern Kunlun orogenic belt. The ultramafic and gabbro samples present mantle-like Mg isotopic compositions, with <em>δ</em>²⁶Mg values ranging from −0.279‰ to −0.266‰ for wehrlite, −0.266‰ to −0.243‰ for clinopyroxenite, and −0.284‰ to −0.253‰ for gabbro. In contrast, the <em>δ</em>²⁶Mg values of the hornblende gabbro samples are significantly higher (−0.195‰ to −0.176‰). These rocks have similar heavy Fe isotopic compositions, with <em>δ</em>⁵⁶Fe values ranging from 0.020‰ to 0.157‰. The high <em>δ</em>²⁶Mg values observed in the hornblende gabbro are interpreted as indicating a maximum of 6% olivine fractionation, whereas the slightly high <em>δ</em>²⁶Mg values in the clinopyroxenite are ascribed to the accumulation of titanomagnetite. The Fe isotopic signatures of these rocks are inherited from magmatic sources. A comparison of the studied rocks with other mafic-ultramafic rocks implies that partial melting of mantle wedges induced by metasomatism of marine sediment-derived melts could generate “dry” arc magmatism, which would necessitate a more comprehensive and detailed analysis in further investigations.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102125"},"PeriodicalIF":8.9,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrochemical characteristics, driving factors and health risk of fluoride in groundwater from the northwestern Ordos Basin, China","authors":"Jiacong Tian ,&nbsp;Zhanjun Wang ,&nbsp;Kyriaki Daskalopoulou ,&nbsp;Maoliang Zhang ,&nbsp;Yaoqiang Huo ,&nbsp;Yingnan Cao ,&nbsp;Jucai Yang ,&nbsp;Wei Liu ,&nbsp;Jianguo Liu ,&nbsp;Sheng Xu","doi":"10.1016/j.gsf.2025.102123","DOIUrl":"10.1016/j.gsf.2025.102123","url":null,"abstract":"<div><div>Groundwater is essential for maintaining public health, promoting economic development, and ensuring ecosystem stability in arid and semi-arid regions. The northwestern Ordos Basin (China) primarily relies on groundwater from multilayered aquifer systems; however, our knowledge of the hydrochemical characteristics and water quality of groundwater in this region is limited. Here, we employed a newly collected dataset of 94 groundwater samples from different aquifers to constrain the source, controlling processes of fluoride in groundwater, and its potential health risk in the area. Groundwater is characterized by Na-Cl and Na-SO₄ types with a minor Na-HCO₃ type, which is primarily controlled by ion exchange, silicate weathering, and the dissolution of carbonate and evaporite minerals. Of the groundwater samples, 42% exceeded the fluoride limit of 1.5 mg/L established by the World Health Organization (WHO). This is mainly attributed to geogenic sources, including fluorine-bearing mineral dissolution, cation exchange, evaporation, and competitive adsorption. The water quality index suggests that most samples are unsuitable for drinking. Health risk assessment results based on the Monte Carlo simulation indicate that children face significantly higher non-carcinogenic health risks from fluoride exposure than adults (both males and females). These findings provide new insights into the complex hydrogeochemical evolution of fluoride in groundwater and the groundwater quality status in multi-aquifer systems, contributing to the sustainable development and management of groundwater resources in the Ordos Basin.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102123"},"PeriodicalIF":8.9,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early Paleozoic subduction initiation in the West Proto-Tethys Ocean: Insights from ophiolitic Speik Complex in the Eastern Alps","authors":"Qingbin Guan ,&nbsp;Yongjiang Liu ,&nbsp;Franz Neubauer ,&nbsp;Johann Genser ,&nbsp;Ruihong Chang ,&nbsp;Boran Liu ,&nbsp;Sanzhong Li ,&nbsp;Qianwen Huang ,&nbsp;Sihua Yuan","doi":"10.1016/j.gsf.2025.102121","DOIUrl":"10.1016/j.gsf.2025.102121","url":null,"abstract":"<div><div>Subduction initiation is a critical part of the plate tectonic system, but its geodynamic process is still poorly understood due to the lack of well-preserved geological records. Based on new zircon U–Pb–Hf isotopic and whole-rock geochemical data, we report the first discovery of a latest Cambrian–Early Ordovician forearc-arc rock sequence in the Eastern Alps. This sequence includes granitic gneisses, amphibolites, and amphibole plagiogneisses from the ophiolitic Speik Complex and Gleinalpe Complex. These rocks exhibit geochemical affinities with typical oceanic plagiogranites, forearc basalts (FABs), and island arc basalts, respectively. The latest Cambrian plagiogranitic protoliths (491 ± 2 Ma) are shearing-type plagiogranites that were formed in the tectonic setting of forearc spreading. The latest Cambrian FABs (496–489 Ma) have similar geochemical compositions and positive <em>ε</em>_Hf(<em>t</em>) values (+2.5 to + 14.9) to the depleted mid-ocean ridge basalts. However, they show depletion in high field strength elements (HFSEs; e.g., Nb, Ta, and Zr) and have relatively low Ti/V ratios. These features suggest that they were derived from a depleted mantle source modified by subducting slab-released components in a forearc environment. The Early Ordovician basaltic protoliths (476–472 Ma) of amphibole plagiogneisses show enrichment in large ion lithophile elements and depletion in HFSEs (e.g. Nb, Ta, Zr, and Hf), implying a mature island arc environment. These metaigneous rocks, along with the coeval boninite-like high-Mg amphibolites near the study area, form a typical rock sequence resembling that of the Izu–Bonin–Mariana (IBM) arc system. The Speik and Gleinalpe complexes document a complete magmatic evolution from subduction initiation to mature arc development within the West Proto-Tethys Ocean. Integrating our new data with published work, we reconstruct the late Ediacaran–early Paleozoic tectonic evolution of the northern Gondwana. During the late Ediacaran–early Cambrian, the rollback of the West Proto-Tethys oceanic plate triggered the separation of the Wechsel-Silvretta-Gleinalpe continental arc from the northern Gondwana. This process led to the formation of the Speik back-arc oceanic basin, a southwestern branch of the West Proto-Tethys Ocean. In the latest Cambrian–Early Ordovician, subduction initiation occurred in the Speik Ocean, which subsequently developed into an intra-oceanic arc system. During the Early Devonian, the Speik Ocean closed and the Wechsel-Silvretta-Gleinalpe continental arc reattached to the Gondwana, as evidenced by the metamorphic event at ca. 400 Ma.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102121"},"PeriodicalIF":8.9,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observed talik development triggers a tipping point in marginal permafrost of the Qinghai-Xizang Plateau","authors":"Dongliang Luo ,&nbsp;Jia Liu ,&nbsp;Fangfang Chen ,&nbsp;Shizhen Li","doi":"10.1016/j.gsf.2025.102122","DOIUrl":"10.1016/j.gsf.2025.102122","url":null,"abstract":"<div><div>Permafrost, a critical component of Earth’s climate system, is increasingly subject to abrupt thaw events, which jeopardize infrastructure, reshape landforms, alter hydrological regimes, and disrupt ecosystems, thereby posing substantial threats to global sustainability. However, the underlying mechanisms that trigger these abrupt transitions remain incompletely understood. Here, we present decade-long <em>in-situ</em> observations from HRQ1, a marginal permafrost site in the Headwater Area of the Yellow River, northeastern Qinghai-Xizang Plateau. These data reveal the formation and growth of a talik, indicative of a permafrost tipping point. Absent before 2017, the talik subsequently formed and progressively deepened, extending to the maximum observation depth of 300 cm by 2024. The transition from perennially frozen to thawed conditions was accompanied by a substantial increase in mean annual soil temperature (MAST) throughout the entire soil profile. From 2015 to 2023, MAST in the upper 200 cm rose from sub-zero (−0.30 to −0.49 °C) to consistently above 0 °C (0.07 to 1.08 °C). Concurrently, maximum daily soil temperatures in deeper layers (200–300 cm) became positive, indicating thaw propagation into the relict permafrost. This warming coincided with a marked increase in unfrozen soil moisture, particularly within the expanding talik. The rapid, non-linear deepening of the talik, far exceeding rates attributable to conductive heat transfer alone, was driven by a strong convective mechanism (Rayleigh-Darcy instability). This advective process was triggered when the soil profile became fully saturated, a condition resulting from the convergence of intensified rainfall and enhanced water retention linked to decadal vegetation greening. Intriguingly, despite the accelerated subsurface warming, the annual amplitude of ground surface temperature decreased from 29.0 ± 2.8 °C to 24.5 ± 3.6 °C following talik formation, likely due to the buffering effect of increased vegetation cover, which modified the surface energy balance. Our results demonstrate that climatic warming and wetting can initiate a cascade of internal feedbacks, propelling marginal permafrost beyond an abrupt tipping point. These findings emphasize the acute vulnerability of marginal permafrost and highlight the urgent necessity for sustained monitoring to assess ecosystem stability and quantify associated greenhouse gas emissions.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102122"},"PeriodicalIF":8.9,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 Paleozoic architecture, deformation, and geodynamics of the Xing’an–Mongolia intracontinental orogenic belt","authors":"Shiyu Song ,&nbsp;Yanlei Zhang ,&nbsp;Xinyu Li ,&nbsp;Qiwei Lu ,&nbsp;Dadi Cao ,&nbsp;Bei Xu","doi":"10.1016/j.gsf.2025.102120","DOIUrl":"10.1016/j.gsf.2025.102120","url":null,"abstract":"<div><div>The architecture and geodynamics of intracontinental orogens remain a fundamental geological challenge. The Xing’an-Mongolia intracontinental orogenic belt (XMIOB), superimposed on the eastern Central Asian Orogenic Belt (CAOB), provides key insights into intracontinental orogenic belt dynamics. However, its architecture, deformation patterns, and geodynamic processes are poorly understood. This study integrates geological mapping, structural analysis, EBSD quartz c-axis fabrics, seismic reflection interpretation, and zircon U-Pb geochronology to unravel the XMIOB’s tectonic evolution and compare it with global intracontinental orogenic belts. Our findings reveal that the XMIOB is shaped by alternating fold-thrust belts and metamorphic zones, dominantly controlled by the inversion of pre-existing extensional structures. EBSD analysis indicates mid-temperature (400 °C – 500 °C) ductile deformation in the deep crust, while seismic profiles highlight structural decoupling driven by a décollement zone. Integrated crustal thickness reconstructions from zircon Eu/Eu* ratios delineate three tectonic stages: Late Carboniferous-Permian asthenospheric upwelling induced crustal thinning from ∼50 km to ∼35 km, forming lithospheric weak zones with Buchan-type metamorphism and bimodal magmatism; Late Permian-Middle Triassic mantle subduction triggered compressional thickening (∼55 km), fold-thrust belt formation, and tectonic inversion of early extensional faults, exposing metamorphic zones; from the Middle Triassic continued mantle subduction and deep-crustal decoupling drove large-scale lateral extrusion and dextral shear, reshaping the XMIOB architecture. Comparisons with global intracontinental orogenic belts highlight two key traits of intracontinental orogenic belt evolution: pre-orogenic lithospheric thinning generates inherited weak zones that localize subsequent deformation; inherited extensional features dictate the final architecture, producing the systematic alternation of metamorphic zones and fold–thrust belts.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102120"},"PeriodicalIF":8.9,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How organic matter types in source rocks influence reservoir diagenesis: Evidence recorded in carbonate cements","authors":"Nianmin Zan ,&nbsp;Kelai Xi ,&nbsp;Yingchang Cao ,&nbsp;Haijun Yang ,&nbsp;Wenfang Yuan ,&nbsp;Tian Yang ,&nbsp;Guoding Yu ,&nbsp;Hao Wang ,&nbsp;Yifan Zhang ,&nbsp;Zhicheng Cui ,&nbsp;Guanghui Yuan","doi":"10.1016/j.gsf.2025.102118","DOIUrl":"10.1016/j.gsf.2025.102118","url":null,"abstract":"<div><div>Fluids generated from the source rocks containing various kerogen types at different thermal maturity stages control diagenetic processes and reservoir quality in adjacent sandstone reservoirs. This study focuses on the carbonate cements in the sandstones of the Lower Jurassic Yangxia Formation and the Ahe Formation in the Tarim Basin. The <em>δ</em>¹⁸O, <em>δ</em>¹³C, and ⁸⁷Sr/⁸⁶Sr data indicate that low‑temperature ferroan calcite and manganoan calcite—characterized by strongly negative <em>δ</em>¹³C values and enrichment in light rare‑earth elements (LREEs)—record CO₂ released during the thermal degradation of organic matter predominantly composed of Type III kerogen in coal‑bearing source rocks and of Type II kerogen in mudstone source rocks, respectively. High‑temperature ferroan calcite and manganoan calcite, which exhibit similarly strongly negative <em>δ</em>¹³C values and enrichment in middle rare‑earth elements (MREEs), record organic acids and CO₂ produced during the thermal decarboxylation of these same source rocks. The diagenetic fluid evolution sequence comprises early‑stage CO₂ from thermal degradation of both coal‑bearing and mudstone source rocks; mid‑stage organic acids and CO₂ from thermal decarboxylation of coal‑bearing source rocks; and late‑stage organic acids and CO₂ from thermal decarboxylation of mudstone source rocks. Fluids generated during the thermal degradation of mudstone and coal‑bearing source rocks precipitated extensive calcite cements, leading to reservoir densification. Clumped isotope thermometry indicates that the primary generation periods of late‑stage mudstone‑derived fluids coincided with the formation of effective fractures. Feldspar dissolution along these fractures produced an interconnected network of fractures and dissolution pores, significantly enhancing reservoir quality in the Ahe Formation.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102118"},"PeriodicalIF":8.9,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}