Journal of Asian Earth Sciences最新文献

{"title":"Contributions of thermoelastic strain to apparent annual variations in four-component borehole strain: A case study from Gaotai station in the NE margin of the Tibetan Plateau","authors":"Xiaolin Yang ,&nbsp;Jinling Yang ,&nbsp;Hang Li ,&nbsp;Jun Wang","doi":"10.1016/j.jseaes.2025.106600","DOIUrl":"10.1016/j.jseaes.2025.106600","url":null,"abstract":"<div><div>Clarifying the physical mechanisms underlying near-surface annual deformation remains a major challenge in crustal dynamics research. For the four-component borehole strain observation networks in mainland China, a few stations are apparently dominated by annual fluctuations. However, only a limited number of specific studies have been carried out to dynamically assess the physical characteristics of these signals. Considering the fact that atmospheric temperature is a major factor inducing annual variations in crustal deformation, the Gaotai station was thus selected as a typical example diagnosis and a half-space model with a decoupling layer was used to quantitatively assess the thermo-effects of annual atmospheric temperature variation on the four-component borehole strain. The results show that an annual temperature variation with amplitude of 16.60 ℃ can induce a theoretical thermal strain of the 10^-6 magnitude at a borehole depth of 44.97 m; additionally, both amplitude and phase of the modeled values closely align with the measured strain time series, suggesting that the annual variation signal of the four-component borehole strain recorded at Gaotai station mainly originates from the annual atmospheric temperature changes. This geodynamical investigation can help to quantitatively elucidate the annual variation mechanism of the multi-component borehole strain and advance our understanding of thermo-deformation processes in shallow crust.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106600"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785812","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":"In3+-Cl− complexation in hydrothermal fluids: Insights from ab initio deep potential molecular dynamics","authors":"Wei Zhang ,&nbsp;Yuanjia Huang ,&nbsp;Li Zhou","doi":"10.1016/j.jseaes.2025.106605","DOIUrl":"10.1016/j.jseaes.2025.106605","url":null,"abstract":"<div><div>Given the rising global demand for indium (In) in electronic devices, research has increasingly focused on its natural mineralogy. The transportation and enrichment of indium are primarily driven by magmatic-hydrothermal processes. However, the speciation of In³⁺ in hydrothermal fluids remains poorly understood. This study developed a first-principle-based deep potential model for the InCl₃-H₂O system aimed to investigate the species of In-Cl complexes. The dissociation pathways of In³⁺-Cl⁻ complexes and the corresponding association constants (log<em>K</em>) for <span><math><mrow><mtext>In</mtext><mtext>C</mtext><msubsup><mtext>l</mtext><mrow><mtext>n</mtext></mrow><mrow><mtext>3-</mtext><mtext>n</mtext></mrow></msubsup><mtext>(</mtext><mtext>n = 1</mtext><mtext>-</mtext><mtext>4</mtext><mtext>)</mtext></mrow></math></span> were investigated via deep potential molecular dynamic simulations (DPMD). These new thermodynamic properties provide the first dataset on <span><math><mrow><mtext>In</mtext><mtext>C</mtext><msubsup><mtext>l</mtext><mrow><mtext>n</mtext></mrow><mrow><mtext>3-</mtext><mtext>n</mtext></mrow></msubsup><mtext>(</mtext><mtext>n = 1</mtext><mtext>-</mtext><mtext>4</mtext><mtext>)</mtext></mrow></math></span> dissociation in high P-T fluids (up to 800 °C and 50 kbar). The Helgeson-Kirkham-Flowers (HKF) parameters for In-Cl complexes were fitted with our DPMD derived log<em>K</em> for In-Cl complexes, which can be serves as a pioneering framework for understanding the stability and speciation of In-Cl complexes in hydrothermal fluids, particularly in the absence of current experimental data. Thermodynamic modeling reveals that In³⁺ has a strong chemical affinity for Cl<strong>⁻</strong>, with high-order In-Cl complexes (InCl₃ and InCl₄^-) playing a critical role in indium transport. Notably, InCl₄^- becomes the predominant species in a very low NaCl concentration (&lt; 1 wt%). Its chemical affinity for Cl<strong>⁻</strong> is stronger than Sn²⁺, and the chemical-physical conditions that favor Sn²⁺-Cl^- complex transportation are equally conducive to indium, resulting in their co-transport when they share the same source. Indium and zinc exhibit similar speciation in hydrothermal fluids, which may advantageously promote the substitution of indium into sphalerite.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106605"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791274","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":"Insights into tectonic lineaments patterns and crustal architectures beneath the Carlsberg Ridge: Implications for mineral exploration","authors":"Satya Narayan","doi":"10.1016/j.jseaes.2025.106602","DOIUrl":"10.1016/j.jseaes.2025.106602","url":null,"abstract":"<div><div>This study focuses on the Carlsberg Ridge’s complex geological structures, characterized by rugged topography, seismicity, and significant hydrothermal activity, which have led to the deposition of economically valuable sulfide minerals. Using an integrated geophysical approach, including gravity data analysis, lineament mapping, Euler depth estimation, seismicity analysis, and spectral depth examination, we investigate the structural and crustal architecture beneath the Carlsberg Ridge. The analysis utilizes high-resolution GECO global gravity models, to generate detailed subsurface images. A comparative study of GECO-derived and shipborne Free-air gravity data shows strong agreement, with higher correlation and lower RMS error. The study also employs the regional-residual gravity separation, edge enhancement filters, and Euler deconvolution method, which aid in identifying mineralization zones and active/inactive vent sites conducive to mineral accumulation. Results indicate topographic and gravity anomalies linked to shallow-to-moderate depth discontinuities, active tectonics, hydrothermal venting, and mineralization processes. Identified zones shows high lineament density, moderate crustal thickness, and shallower Moho depths. The THVH technique delineated faults and fractures with dominant orientations of NE-SW, NW-SE, ENE-WSW, N-S, and E-W directions, respectively. Seismic events along the ridge axis, with focal depths of 9.0–10.5 km and magnitudes of 4.0–5.9 Mb, correlate with these zones. Mineralized areas align with high seismicity, shallow crustal features, and hydrothermal vent activity. These findings emphasize the Carlsberg Ridge’s potential for deep-sea mineral exploration, offering valuable insights into seafloor mineralization processes. This study provides a foundation for future geophysical and geochemical surveys in mid-oceanic ridge environments.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106602"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799257","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":"Three groups of arthropods (Chasmataspidida, Offacolidae (?), and Euthycarcinoidea) cohabited a tidal zone in the late Cambrian paleobasins (495–488 Ma) of Eastern Siberia","authors":"Elena Naimark ,&nbsp;Alexander Sizov","doi":"10.1016/j.jseaes.2025.106595","DOIUrl":"10.1016/j.jseaes.2025.106595","url":null,"abstract":"<div><div>We examined arthropods from a newly discovered location, Kimiltei, in the Irkutsk region of Eastern Siberia. These arthropods belong to three distinct groups: basal euchelicerate (putative Offacolidae), Chasmataspidida, and Euthycarcinoidea. They were found together in a single bed. Chemical, mineralogical, and facial analyses revealed that this bed was formed within a very shallow lagoonal/tidal environment with nearby paleosols. Using the combined data, we present a taphonomic model explaining the uncompressed, three-dimensional preservation of the arthropods. Based on U-Pb isotopic dating of detrital zircon grains, we determined the age of this bed as 491.3 ± 4.2 Ma, placing it in the Furongian Series (Jiangshanian and Stage 10). Given this age, the arthropods from Kimiltei appear to be among the earliest known body fossils of Euthycarcinoidea and euchelicerates. An updated analysis of the geographical distribution of these groups indicate<del>s</del> that by the late Cambrian, Euthycarcinoidea already had a wide distribution in tropical and possibly boreal regions of the Iapetus Ocean, while euchelicerates inhabited a tropical Siberian paleobasin. The evolution of these groups proceeded at the beginning in close ecological niches in a tidal zone.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"289 ","pages":"Article 106595"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800244","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":"Age, kinematics, and magnitude of the last surface rupturing event along the central Pambak-Sevan-Syunik fault (Armenia): Probable implications for landslides and lake tsunamis","authors":"Ara Avagyan ,&nbsp;Jean-Francois Ritz ,&nbsp;Seda Avagyan ,&nbsp;Gagik Alaverdyan ,&nbsp;Anastasia Arzhannikova ,&nbsp;Sergey Arzhannikov ,&nbsp;Lilit Sahakyan ,&nbsp;Tigran Armenyan ,&nbsp;Farkhod Hakimov ,&nbsp;Ruben Badalyan","doi":"10.1016/j.jseaes.2025.106603","DOIUrl":"10.1016/j.jseaes.2025.106603","url":null,"abstract":"<div><div>The Lesser Caucasus region is located in the northern part of the Armenian Highland, within the active Arabia-Eurasian collision zone. Numerous and various geological hazards, such as large earthquakes can be observed in this region. They can reach M7^± magnitude inducing surface ruptures and strong ground shaking that in turn can trigger landslides and liquefaction phenomena. One of the most important sources of earthquakes is the Pambak-Sevan-Syunik fault (PSSF), which crosses the entire Armenian territory including Lake Sevan with population estimated at 280,000 around it. In this work, we conducted a paleoseismological study along the Vanadzor-Artanish segment of the PSSF, on the northern shore of the Lake Sevan. Our findings indicate that this fault produced a M_w 7.2 earthquake between 901 and 2333 cal. BC resulting in a surface rupture of at least 22 km and a vertical displacement component of approximately 2 m. Based on our observations, this large earthquake most likely triggered associated phenomena such as landslides and a lake tsunami. These new results demonstrate that characterizing the paleoseismology of active faults in mountainous regions, especially in densely populated areas like Armenia, must be combined with the analysis of potential associated phenomena to provide a complete geohazards assessment.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106603"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical signatures and chemostratigraphic framework for the Early-Middle Permian sedimentary successions of Alborz, Iran","authors":"Forough Abasaghi,&nbsp;Armin Omidpour","doi":"10.1016/j.jseaes.2025.106607","DOIUrl":"10.1016/j.jseaes.2025.106607","url":null,"abstract":"<div><div>This research analyzes how the prevailing physicochemical conditions during the deposition of the carbonate intervals of the Ruteh Formation (Early-Middle Permian), in the Alborz, Iran, led to changes in water-column redox conditions. The significance of this study lies in providing unique insights into the oxic-anoxic variations in the Tethys Ocean during the detachment of the western Cimmerian microcontinent from Gondwana. The onset of interglacial periods and the opening of the Neo-Tethys in the Artinskian stage led to rising temperatures, oxic conditions, and a decrease in the enrichment factor and carbon isotope values. In contrast, the Kungurian oceans were suboxic to anoxic, as evidenced by positive carbon isotope values, high enrichment factor, positive Eu and Ce anomalies, and increased primary productivity. These geochemical changes are attributed to volcanic activities in the Early Kungurian, followed by the transgression of seawater during the opening of the Neo-Tethys and the movement of the Cimmerian microcontinent in the Late Kungurian. These factors played a crucial role in the development of oxygen-deficient basins and the upwelling processes. During the Roadian stage, oxic conditions once again dominated in the basin. The increase in temperature, coupled with the Cimmerian microcontinent’s movement towards equatorial latitudes, may have been a significant factor contributing to the decrease in carbon isotopic values, enrichment factor, and productivity proxies. The results obtained extend beyond previous studies, demonstrating that the deposition of the Ruteh Formation was closely linked to global events.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"288 ","pages":"Article 106607"},"PeriodicalIF":2.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799258","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 early carboniferous and early Permian mafic intrusions in the Nanpanjiang Basin, SW China: Implications for northward subduction of the East Paleo-Tethys Ocean and back-arc basin formation","authors":"Xin Zhu ,&nbsp;Xiao-Ping Xia ,&nbsp;Jian Xu ,&nbsp;Qing Yang ,&nbsp;Zexian Cui ,&nbsp;M.P. Manu Prasanth","doi":"10.1016/j.jseaes.2025.106597","DOIUrl":"10.1016/j.jseaes.2025.106597","url":null,"abstract":"<div><div>The Nanpanjiang Basin (NPJB) is situated along the margins of the South China block (SCB) and the Indochina block (ICB). Its position is significant for evaluating the amalgamation histories of the two blocks, which shaped present-day Southeast Asia. However, the geological community has yet to reach a consensus on the formation and evolutionary history of the NPJB. Two competing models, which include the back-arc and foreland basins, have been proposed so far. This work employs apatite U-Pb dating and oxygen isotopes, whole-rock element and Sr-Nd isotope analyses on the Funing-Napo mafic intrusions (FNMI) in the Chinese Guangxi to evaluate the magmatic and tectonic aspects of the NPJB. The studied mafic intrusions are divisible into two groups based on their apatite ages: the Early Carboniferous (349–347 Ma, Group 1) and the Early Permian (295–284 Ma, Group 2). Group 1 samples display low SiO₂ (46.5–51.1 wt%) and high MgO (6.01–9.47 wt%). Group 2 samples show lower SiO₂ (44.5–49.2 wt%) and more variable MgO (3.39–13.7 wt%). Geochemical modeling based on the trace elements and isotopic compositions demonstrates that the FNMI were derived from an asthenosphere mantle source with OIB-like geochemical characteristics, metasomatized by melts originating from subducted sediments. The northward subduction of the East Paleo-Tethys Ocean (EPTO) beneath the SCB likely caused the onset of a back-arc extensional tectonic regime since the Early Carboniferous. The NPJB developed as a back-arc basin and facilitated a series of mafic magmatism in the Funing-Napo and surrounding areas during the Early Carboniferous and Early Permian.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106597"},"PeriodicalIF":2.7,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonic uplift since the late Mesozoic and early geomorphological development of the north Qilian Shan on the NE Tibet Plateau: Insights from low–temperature thermochronology","authors":"Zheng Wenjun ,&nbsp;Wei Shiqi ,&nbsp;Jia Jiabao ,&nbsp;Wang Weitao ,&nbsp;Sun Xin ,&nbsp;Liu Bingxu","doi":"10.1016/j.jseaes.2025.106571","DOIUrl":"10.1016/j.jseaes.2025.106571","url":null,"abstract":"<div><div>The uplift history of the Qilian Shan and the formation time of modern landforms are key factors in establishing a northward expansion model of the Tibetan Plateau, although previous studies have obtained comprehensive results and an understanding of the areas at both ends of the Qilian Shan. The Gaizhangdaban Shan area, located in the mid–eastern section of the northern Qilian Shan, is characterized by the interplay of granite and Cambrian metamorphic strata, which collectively contribute to the pronounced topographical features in the central part of the Qilian Shan–Hexi Corridor. We employed apatite (U–Th)/He and zircon (U–Th)/He thermochronology, revealing a range of dates predominantly spanning from 300 Ma to 75 Ma. The cooling path model derived from our thermochronological data elucidates two distinct cooling events, dated at ∼78 Ma and ∼15 Ma respectively. Through a comparative analysis of the thermal history across the Qilian Shan range, we proposed that a progressive uplift extending from southern to northern regions commenced in the Late Cretaceous and occurred almost concurrently during the Miocene. We hypothesized that the Late Cretaceous cooling event was influenced primarily by the far–field effects of the collision between the Lhasa and Qiangtang blocks. The subsequent rapid Miocene uplift event is attributed to the closure of the Neo–Tethys Ocean and the consequent outward expansion of the Tibetan Plateau.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106571"},"PeriodicalIF":2.7,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759799","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":"Orogenic segmentation across central and eastern Himalaya: Insights from source parameters derived from local earthquakes","authors":"Mita Uthaman,&nbsp;Chandrani Singh,&nbsp;Arun Singh,&nbsp;Abhisek Dutta","doi":"10.1016/j.jseaes.2025.106567","DOIUrl":"10.1016/j.jseaes.2025.106567","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Orogenic segmentation across the arcuate Himalayan belt complicates deformational trends beyond central Nepal. Here, we attempt to discern the implications of spatially varying deformation on seismic hazard potential in eastern Nepal, Sikkim and Bhutan Himalayas. A comprehensive catalogue of 2,018 local earthquakes recorded during past deployments is utilized to estimate source parameters from P and S wave spectra. Results indicate stress drop (Δσ) and moment magnitude exhibit scaled dependence with linearly increasing relation. Scaling traced between seismic moment and corner frequency (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mo&gt;∝&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;sup&gt;protect relax special {t4ht=−}3&lt;/sup&gt;) indicates no breakdown of earthquake scaling law for small earthquakes, thus holding potential to be scaled for modelling large earthquakes in the region. Empirical relationships established (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=0.55&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;+1.43, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=0.68&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;)-6.20; &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=0.61&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;+1.33, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=0.66&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;)-6.06; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=0.66&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;+1.37, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=0.66&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;)-5.94) can serve as input for seismic hazard assessment in eastern Nepal, Sikkim and Bhutan. Spatial variability of Δσ is reflective of high coupling along the Main Himalayan Thrust (MHT), high strain rate and lower seismic activity in eastern Nepal and Bhutan. Strike-slip faulting in Bhutan (along DCFZ and KFZ) releases higher Δσ (&lt;span&gt;&lt;math&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;7–15 MPa) as compared to thrusting in Nepal releasing lower Δσ (&lt;span&gt;&lt;math&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;2 MPa). Low coupling along","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106567"},"PeriodicalIF":2.7,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739013","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":"Effect of extractable organic matter on nanopore structure and heterogeneity in Triassic Yanchang lacustrine shale of the Ordos basin, China","authors":"Ruiliang Guo ,&nbsp;Xiaowei Liang ,&nbsp;Xinping Zhou ,&nbsp;Zhiqiang Fan ,&nbsp;Jingzhou Zhao ,&nbsp;Yubin Bai ,&nbsp;Weitao Wu ,&nbsp;Lei Cao ,&nbsp;Peng Liu","doi":"10.1016/j.jseaes.2025.106577","DOIUrl":"10.1016/j.jseaes.2025.106577","url":null,"abstract":"<div><div>The low-pressure nitrogen adsorption and multifractal analysis of Triassic Yanchang Chang 7 shale samples, before and after solvent extraction, were conducted on the effect of extractable organic matter (EOM) on pore microstructure, porosity, and heterogeneity. Chang 7 Shale, primarily composed of type II₁-II₂ organic matter (OM) and argillaceous-siliceous lithofacies, is characterized by interparticle and intraparticle pores in inorganic minerals, with limited development of OM pores. After extraction, pore volume and specific surface area significantly increased from 2.91 cm³/1000 g to 4.43 cm³/1000 g and 0.61 m²/g to 1.91 m²/g, respectively. This increase is attributed to the reopening of minor pores (&lt;23 nm) previously occupied by saturated hydrocarbons, which enhanced the proportion of minor pores and reduced overall pore heterogeneity. Saturated hydrocarbons in EOM were mainly enriched in carbonate interparticle pores, while aromatic hydrocarbons were concentrated in pyrite intraparticle pores. Resins and asphaltenes were predominantly adsorbed onto OM and inorganic mineral surfaces. Clay and pyrite intraparticle pores were nearly completely filled with EOM, reducing heterogeneity, whereas detrital mineral interparticle pores, partially filled with EOM, increased heterogeneity. A linear correlation between EOM content and Rock-Eval S₁ suggests that sample crushing may lead to an underestimation of saturated hydrocarbon content in S₁. These findings provide critical insights into the pore structure evolution and shale oil enrichment mechanisms in Yanchang Shale.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"287 ","pages":"Article 106577"},"PeriodicalIF":2.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684272","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}