Pub Date : 2025-11-20DOI: 10.1016/j.geogeo.2025.100480
Rima Rachmayani , Nabilah Shafira Milennianti
Climate change and steric variables influence sea level rise in the modern era. This study used the Community Climate System Model version 4 (CCSM4) to compare sea surface temperature (SST) and sea level height (SSH) in Indonesia during the mid-Holocene (MH), pre-industrial (PI), and future periods in 2300 with Representative Concentration Pathways 8.5 (RCP8.5). The results show that the average SST value is lower in the MH, with a change in values of around −1°C in the MAM season and increases in the future by around 2°C, whereas the average SSH value is lower in the MH with a change in values of around −0.1 m during the SON season in Western Sumatra and increases in the future over the SON season by around 0.1 m in Northern Papua, compared to PI. The average correlation between the two metrics is positive, with values of 0.55 (MH-PI) and 0.8 (RCP8.5-PI). SST and SSH climatological patterns in Western Sumatra, the Banda Sea, and Northern Papua reveal that SST and SSH fall during the JJA season and increase during the SON season, respectively. This fluctuation is produced by either a lag in insolation or the winter remnant effect. Signal analysis with Fourier transform reveals that the major signal spectrum for changes in SST and SSH is contributed by annual and semi-annual periodicity in the three regions. A notable interannual periodicity exists; however, it is not predominant, leading to variable interannual influences on SST and SSH in Indonesia.
{"title":"Astronomical and greenhouse gas configuration from past to future simulation: An analysis of sea surface temperature's impact on sea levels in Indonesia","authors":"Rima Rachmayani , Nabilah Shafira Milennianti","doi":"10.1016/j.geogeo.2025.100480","DOIUrl":"10.1016/j.geogeo.2025.100480","url":null,"abstract":"<div><div>Climate change and steric variables influence sea level rise in the modern era. This study used the Community Climate System Model version 4 (CCSM4) to compare sea surface temperature (SST) and sea level height (SSH) in Indonesia during the mid-Holocene (MH), pre-industrial (PI), and future periods in 2300 with Representative Concentration Pathways 8.5 (RCP8.5). The results show that the average SST value is lower in the MH, with a change in values of around −1°C in the MAM season and increases in the future by around 2°C, whereas the average SSH value is lower in the MH with a change in values of around −0.1 m during the SON season in Western Sumatra and increases in the future over the SON season by around 0.1 m in Northern Papua, compared to PI. The average correlation between the two metrics is positive, with values of 0.55 (MH-PI) and 0.8 (RCP8.5-PI). SST and SSH climatological patterns in Western Sumatra, the Banda Sea, and Northern Papua reveal that SST and SSH fall during the JJA season and increase during the SON season, respectively. This fluctuation is produced by either a lag in insolation or the winter remnant effect. Signal analysis with Fourier transform reveals that the major signal spectrum for changes in SST and SSH is contributed by annual and semi-annual periodicity in the three regions. A notable interannual periodicity exists; however, it is not predominant, leading to variable interannual influences on SST and SSH in Indonesia.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100480"},"PeriodicalIF":0.0,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing more sophisticated as well as efficient exploration methods to identify the hidden ore bodies are necessary to meet the world wide increasing demand of mineral resources. In this regard, mineral prospectivity mapping (MPM) is crucial. This study undertakes a pioneering effort to apply and compare four machine learning (ML) models—random forest (RF), XGBoost (XGB), support vector classifier (SVC) and artificial neural network (ANN)—for gold prospectivity mapping within the Archean Dharwar Craton, India. The primary goals included the development and evaluation of these models, a systematic assessment of their comparative performance through cross-validation, feature important analysis and ultimately, production of prospectivity map. The culmination of this work is a high-resolution, combined prospectivity map, designed to produce a new prospectivity areas. Diverse geospatial data was meticulously integrated as per mineral system of the area, including geological maps, structural lineaments, geochemical, geophysical and ASTER remote sensing imagery. For model training, 79 known gold occurrences were carefully collected alongside an equal number of selected non-occurrence locations, framing the task as a supervised binary classification problem. Rigorous evaluation, employing 5-fold cross-validation and a 70:30 train-test split, confirmed the exceptional capabilities of these models. XGB and RF consistently emerged as top performers, with impressive AUC-ROC values of 0.9992 and 0.9965, respectively, coupled with high precision, recall and F1-scores and few false positives or negatives. While ANN also showed excellent performance, SVC, though strong, yielded comparatively lower metrics. A detailed feature importance analysis exhibits the positive role of Meta-Basalt, geochemical principal component 1 and Bouguer gravity anomaly and its derivative maps. Success-rate curves vividly illustrated the models' efficiency capturing over 76% of known occurrences within just 20% of the highest-ranked areas shows targeting precision. The generated combined prospectivity map, a robust synthesis from XGB, RF and ANN, based on a stringent consensus criterion validates existing knowledge and precisely delineates high-priority exploration targets, fundamentally reshaping the approach to future mineral exploration.
{"title":"Advanced machine learning based gold prospectivity mapping in the Dharwar Craton, India: A hybrid knowledge-data driven paradigm integrating ensemble and deep learning","authors":"Soumya Mitra , Saptarshi Mallick , Santu Biswas , Kshounish Patra","doi":"10.1016/j.geogeo.2025.100473","DOIUrl":"10.1016/j.geogeo.2025.100473","url":null,"abstract":"<div><div>Developing more sophisticated as well as efficient exploration methods to identify the hidden ore bodies are necessary to meet the world wide increasing demand of mineral resources. In this regard, mineral prospectivity mapping (MPM) is crucial. This study undertakes a pioneering effort to apply and compare four machine learning (ML) models—random forest (RF), XGBoost (XGB), support vector classifier (SVC) and artificial neural network (ANN)—for gold prospectivity mapping within the Archean Dharwar Craton, India. The primary goals included the development and evaluation of these models, a systematic assessment of their comparative performance through cross-validation, feature important analysis and ultimately, production of prospectivity map. The culmination of this work is a high-resolution, combined prospectivity map, designed to produce a new prospectivity areas. Diverse geospatial data was meticulously integrated as per mineral system of the area, including geological maps, structural lineaments, geochemical, geophysical and ASTER remote sensing imagery. For model training, 79 known gold occurrences were carefully collected alongside an equal number of selected non-occurrence locations, framing the task as a supervised binary classification problem. Rigorous evaluation, employing 5-fold cross-validation and a 70:30 train-test split, confirmed the exceptional capabilities of these models. XGB and RF consistently emerged as top performers, with impressive AUC-ROC values of 0.9992 and 0.9965, respectively, coupled with high precision, recall and F1-scores and few false positives or negatives. While ANN also showed excellent performance, SVC, though strong, yielded comparatively lower metrics. A detailed feature importance analysis exhibits the positive role of Meta-Basalt, geochemical principal component 1 and Bouguer gravity anomaly and its derivative maps. Success-rate curves vividly illustrated the models' efficiency capturing over 76% of known occurrences within just 20% of the highest-ranked areas shows targeting precision. The generated combined prospectivity map, a robust synthesis from XGB, RF and ANN, based on a stringent consensus criterion validates existing knowledge and precisely delineates high-priority exploration targets, fundamentally reshaping the approach to future mineral exploration.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100473"},"PeriodicalIF":0.0,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To assess drought risk, susceptibility to food security, and water resource utilization, it is crucial to comprehend dry spell patterns from a hydrological perspective. Some regional studies have noted an extension of dry spells on a global and regional scale, but it is still unclear how often dry spells occur during the summer monsoon season, which is dominated by rainfall. This study uses the Mann-Kendall trend test to examine the trend of dry spells during Bangladesh's summer monsoon from 1985 to 2022 to close this gap. Using the frontier atmospheric general circulation model and remote sensing methods to examine the effects of ocean elements such as Indian Ocean Dipole (IOD), sea surface temperature (SST), El Niño-southern oscillation (ENSO) conditions, and the zonal wind. Daily rainfall data for 34 weather stations were obtained from the Bangladesh Meteorological Department, while surface water occurrence and change intensity data were retrieved from the JRC Global Surface Water Mapping Layers, v1.3 (FAO, UN). The NOAA Physical Sciences Laboratory (PSL) and the Tokyo Climate Center/WMO Regional Climate Centre in RA II (Asia) provided the IOD, SST, ENSO, and zonal wind data. A notable dry spell anomaly over Bangladesh was also observed in this research, with short, medium-length, and long dry spells increasing at 82.35 %, 73.53 %, and 50 % of the weather stations, respectively. Dry spells become less frequent during El Niño but more during La Niña. The climatic variability of IOD events and SST anomalies in the eastern and western tropical Indian Ocean was also noted by this study to be connected to these anomalous events. The correlation coefficient between summer monsoon rainfall and DMI is 0.34. Throughout the study period, there were changes in the upper atmosphere's and lower troposphere's wind circulation. The study allows the prioritization of regions for drought, effective water resource management, and food scarcity preparedness.
{"title":"Analysis of the trend of dry spells and how ocean factors affect their patterns during the summer monsoon in Bangladesh using the Mann-Kendall and frontier atmospheric general circulation model","authors":"Md. Moniruzzaman Monir , Subaran Chandra Sarker , Md. Mostafizur Rahman , Md. Nazrul Islam","doi":"10.1016/j.geogeo.2025.100472","DOIUrl":"10.1016/j.geogeo.2025.100472","url":null,"abstract":"<div><div>To assess drought risk, susceptibility to food security, and water resource utilization, it is crucial to comprehend dry spell patterns from a hydrological perspective. Some regional studies have noted an extension of dry spells on a global and regional scale, but it is still unclear how often dry spells occur during the summer monsoon season, which is dominated by rainfall. This study uses the Mann-Kendall trend test to examine the trend of dry spells during Bangladesh's summer monsoon from 1985 to 2022 to close this gap. Using the frontier atmospheric general circulation model and remote sensing methods to examine the effects of ocean elements such as Indian Ocean Dipole (IOD), sea surface temperature (SST), El Niño-southern oscillation (ENSO) conditions, and the zonal wind. Daily rainfall data for 34 weather stations were obtained from the Bangladesh Meteorological Department, while surface water occurrence and change intensity data were retrieved from the JRC Global Surface Water Mapping Layers, v1.3 (FAO, UN). The NOAA Physical Sciences Laboratory (PSL) and the Tokyo Climate Center/WMO Regional Climate Centre in RA II (Asia) provided the IOD, SST, ENSO, and zonal wind data. A notable dry spell anomaly over Bangladesh was also observed in this research, with short, medium-length, and long dry spells increasing at 82.35 %, 73.53 %, and 50 % of the weather stations, respectively. Dry spells become less frequent during El Niño but more during La Niña. The climatic variability of IOD events and SST anomalies in the eastern and western tropical Indian Ocean was also noted by this study to be connected to these anomalous events. The correlation coefficient between summer monsoon rainfall and DMI is 0.34. Throughout the study period, there were changes in the upper atmosphere's and lower troposphere's wind circulation. The study allows the prioritization of regions for drought, effective water resource management, and food scarcity preparedness.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100472"},"PeriodicalIF":0.0,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-06DOI: 10.1016/j.geogeo.2025.100471
Sudipta Pal, Nibedita Das Pan
Among all the environmental issues of the world, soil erosion is of significant concern in terms of watershed management. For proper planning and management of watersheds in terms of soil erosion, characterization and prioritization of sub-watersheds (SWs) through appropriate techniques is crucial. Thus the present study focuses on prioritizing the erosion prone sub-watersheds of Haora Drainage Basin, Tripura using Hydro-Morphometric analysis. Remote sensing (RS) and geographical information system (GIS) play a vital role for providing cost-effective and accurate data of the study area. The generation of drainage networks and delineation of sub-watersheds has been done using ASTER DEM of 30 m resolution in the Arc-GIS 10.8 software. On one hand, nineteen vital morphometric parameters among the linear, areal and relief aspects in relation to soil erodibility were computed using pre-defined mathematical formulae and methods using the DEM and on the other hand, field surveys with necessary equipment for three consecutive water years (2021–2024) helped in evaluating six important hydrological parameters. The study area consists of nine sub-watersheds in order of SW1-SW9. The prioritization of the sub-watersheds has been done on the basis of compound value of each sub-watershed calculated by using the Preliminary Rankings of the parameters and weighted sum approach (WSA). As a result, SW5, SW7 and SW3 have been categorized into high priority and SW9 and SW1 comes under moderate priority. Four sub-watersheds namely SW6, SW4, SW8 and SW2 have been assigned low priority, suggesting that these are more sustainable than others. The study provides scientific information for decision makers toward effective soil and watershed management.
{"title":"Prioritization of sub-watersheds based on hydro-morphometric assessment in relation to soil erosion: A case study in Haora Drainage Basin, Tripura","authors":"Sudipta Pal, Nibedita Das Pan","doi":"10.1016/j.geogeo.2025.100471","DOIUrl":"10.1016/j.geogeo.2025.100471","url":null,"abstract":"<div><div>Among all the environmental issues of the world, soil erosion is of significant concern in terms of watershed management. For proper planning and management of watersheds in terms of soil erosion, characterization and prioritization of sub-watersheds (SWs) through appropriate techniques is crucial. Thus the present study focuses on prioritizing the erosion prone sub-watersheds of Haora Drainage Basin, Tripura using Hydro-Morphometric analysis. Remote sensing (RS) and geographical information system (GIS) play a vital role for providing cost-effective and accurate data of the study area. The generation of drainage networks and delineation of sub-watersheds has been done using ASTER DEM of 30 m resolution in the Arc-GIS 10.8 software. On one hand, nineteen vital morphometric parameters among the linear, areal and relief aspects in relation to soil erodibility were computed using pre-defined mathematical formulae and methods using the DEM and on the other hand, field surveys with necessary equipment for three consecutive water years (2021–2024) helped in evaluating six important hydrological parameters. The study area consists of nine sub-watersheds in order of SW1-SW9. The prioritization of the sub-watersheds has been done on the basis of compound value of each sub-watershed calculated by using the Preliminary Rankings of the parameters and weighted sum approach (WSA). As a result, SW5, SW7 and SW3 have been categorized into high priority and SW9 and SW1 comes under moderate priority. Four sub-watersheds namely SW6, SW4, SW8 and SW2 have been assigned low priority, suggesting that these are more sustainable than others. The study provides scientific information for decision makers toward effective soil and watershed management.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100471"},"PeriodicalIF":0.0,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study delineates zones of potential mineralization within the Chhotanagpur Gneissic Complex (CGC) using integrated geophysical methods. Comprehensive gravity and magnetic surveys were conducted across ∼3500 km² revealing seven high–priority blocks characterized by distinct Bouguer gravity anomalies (–46 to –19 mGal) and magnetic intensity variations (–246 to +710 nT). These geophysical anomalies are linked to surface lithologies like mica–schist belts, amphibolites and intrusive bodies which are indicative of economically significant mineral deposits. In this study, structural analysis highlights NE–SW and NW–SE trending lineaments and faults that may play a key control on mineralization in the area. Depth estimations from radially averaged power spectrum (RAPS) and Euler 3D solutions shows causative bodies are deeper (∼4 km) in western region than the eastern region (∼1–2 km). The integration of geophysical data with geological interpretations enhances understanding of the CGC in the context of possible influence on mineralization processes. The present findings provide a strategic pathway for guiding further mineral exploration initiatives in seven potential zones identified in the study area.
{"title":"Identification of structurally controlled potential mineralization zones in Chhotanagpur Gneissic Complex, Eastern India from gravity and magnetic data","authors":"Afaque Karim , Anurag Tripathi , Upananda Low , Mohd Tabish Ansari , Deepak Yadav , Kashi Nath Prasad","doi":"10.1016/j.geogeo.2025.100470","DOIUrl":"10.1016/j.geogeo.2025.100470","url":null,"abstract":"<div><div>The present study delineates zones of potential mineralization within the Chhotanagpur Gneissic Complex (CGC) using integrated geophysical methods. Comprehensive gravity and magnetic surveys were conducted across ∼3500 km² revealing seven high–priority blocks characterized by distinct Bouguer gravity anomalies (–46 to –19 mGal) and magnetic intensity variations (–246 to +710 nT). These geophysical anomalies are linked to surface lithologies like mica–schist belts, amphibolites and intrusive bodies which are indicative of economically significant mineral deposits. In this study, structural analysis highlights NE–SW and NW–SE trending lineaments and faults that may play a key control on mineralization in the area. Depth estimations from radially averaged power spectrum (RAPS) and Euler 3D solutions shows causative bodies are deeper (∼4 km) in western region than the eastern region (∼1–2 km). The integration of geophysical data with geological interpretations enhances understanding of the CGC in the context of possible influence on mineralization processes. The present findings provide a strategic pathway for guiding further mineral exploration initiatives in seven potential zones identified in the study area.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100470"},"PeriodicalIF":0.0,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.geogeo.2024.100345
Irina Sotnikova , Anna Spivak , Alla Viryus , Michael Kuzmin , Egor Zakharchenko , Tatiana Kolotilina , Natalia Alymova
The typomorphic features and ages of monazites from two zones of ore-bearing pegmatites of the Burpala massif (Western and Britolite) were studied. This made it possible to clarify the stages of formation of the vein phase of the intrusive rocks. Information on the relationship of monazites with rock-forming and ore minerals was also obtained. Using the CHIME method, the isochronous Th-U-Pb age of monazites from rare-metal pegmatites was calculated: 287 ± 54 Ma (Western zone) and 273 ± 69 Ma (Britholite zone). The obtained age values for the rare-metal pegmatites of the Burpala massif are in good agreement with the available geological and geochronological information and indicate the existence of several stages of their formation, which allows us to supplement the magmatism scheme of the vein complex (mariupolites → foyaites → rare-metal pegmatites of the Western zone → rare-metal pegmatites of the Britholite zone → apatite-fluorite rocks → carbonatites→ alaskites and alkaline granites). The obtained age for monazites from two zones of pegmatites is close by time of formation to the pulaskites of the main phase and rare-metal pegmatites of the North-Western zone of the Burpala massif and belongs to the general Late Paleozoic stage of intraplate magmatism in the northern framing of the Angara-Vitim batholith.
{"title":"Stage of the vein series formation processes of the Burpala massif (North Baikal), according to chemical microprobe Th-U-Pb dating of monazites","authors":"Irina Sotnikova , Anna Spivak , Alla Viryus , Michael Kuzmin , Egor Zakharchenko , Tatiana Kolotilina , Natalia Alymova","doi":"10.1016/j.geogeo.2024.100345","DOIUrl":"10.1016/j.geogeo.2024.100345","url":null,"abstract":"<div><div>The typomorphic features and ages of monazites from two zones of ore-bearing pegmatites of the Burpala massif (Western and Britolite) were studied. This made it possible to clarify the stages of formation of the vein phase of the intrusive rocks. Information on the relationship of monazites with rock-forming and ore minerals was also obtained. Using the CHIME method, the isochronous Th-U-Pb age of monazites from rare-metal pegmatites was calculated: 287 ± 54 Ma (Western zone) and 273 ± 69 Ma (Britholite zone). The obtained age values for the rare-metal pegmatites of the Burpala massif are in good agreement with the available geological and geochronological information and indicate the existence of several stages of their formation, which allows us to supplement the magmatism scheme of the vein complex (mariupolites → foyaites → rare-metal pegmatites of the Western zone → rare-metal pegmatites of the Britholite zone → apatite-fluorite rocks → carbonatites→ alaskites and alkaline granites). The obtained age for monazites from two zones of pegmatites is close by time of formation to the pulaskites of the main phase and rare-metal pegmatites of the North-Western zone of the Burpala massif and belongs to the general Late Paleozoic stage of intraplate magmatism in the northern framing of the Angara-Vitim batholith.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100345"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.geogeo.2025.100388
Igor V. Ashchepkov , N.V. Chalapathi Rao , Rohit Pandey , Sergei V. Rasskazov
{"title":"Geochemistry and petrology of deep seated mantle magmas and their mantle xenoliths and xenocrysts: Applications to the structure and compositions of mantle lithosphere","authors":"Igor V. Ashchepkov , N.V. Chalapathi Rao , Rohit Pandey , Sergei V. Rasskazov","doi":"10.1016/j.geogeo.2025.100388","DOIUrl":"10.1016/j.geogeo.2025.100388","url":null,"abstract":"","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100388"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.geogeo.2025.100383
M. Lachhana Dora , Hassan M. Helmy , Rajkumar Meshram , Nathala K. Rao , Mohamad Shareef , Raghuram , Vivek P. Malviya , Tushar Meshram , Srinivas Rao Baswani , Mohammad Atif Raza , Kirtikumar Randive
This study presents the first identification of an Alaskan-type intrusion within the late-Proterozoic Padhar mafic-ultramafic complex (PMUC), situated along the Central Indian Tectonic Zone (CITZ). The intrusion exhibits a differentiated composition, including peridotite, pyroxenites, hornblende gabbros and diorite. We adopt an integrated approach that combines field studies with analyses of major oxides, in-situ trace elements, and rare-earth element geochemistry. The field evidences of PMUC displays concentric zoning, with a core of dunite surrounded by wehrlite, olivine clinopyroxenite, clinopyroxenite, hornblende clinopyroxenite, and gabbro akin to Alaskan type intrusions. The primary minerals in the PMUC include olivine (forsterite), pyroxene (Cpx and Opx), amphibole, phlogopite, chromite, and magnetite, while secondary minerals like serpentine, chlorite, and talc are also present. The increase in magnesian number (Mg#) of olivine (70–77), orthopyroxene (53–73), and clinopyroxene (67–88) from mafic to ultramafic units indicates differentiation from a common parent melt. The geochemical signature, including negative Nb and Zr anomalies and positive Rb anomalies, suggests fluid metasomatism from slab sediments. The presence of a hydrous parent magma is inferred from the Mg# of early-formed olivine and high amphibole content. Tectonic discrimination plots of pyroxene and amphibole minerals, combined with in-situ trace element chemistry and bulk rock geochemistry, indicate an arc-related origin. The data suggest fluid-driven subduction zone metasomatism, characteristic of Proterozoic Alaskan-type tectonics within the CITZ. Platinum-group element geochemistry shows a high (Pt + Pd)/(Ir + Ru) ratio, similar to that of intrusive rocks of Alaskan types. Geological and geochemical data further support that the PMUC represents a shallow-level (ca. 17 km) segment of a Proterozoic arc, with minor ultramafic units acting as conduits for arc magma in the Betul Belt.
{"title":"Proterozoic arc magmatism from the Padhar mafic-ultramafics in Betul Belt, Central India Tectonic Zone: Insight from petrography, bulk rock and in-situ trace element geochemistry","authors":"M. Lachhana Dora , Hassan M. Helmy , Rajkumar Meshram , Nathala K. Rao , Mohamad Shareef , Raghuram , Vivek P. Malviya , Tushar Meshram , Srinivas Rao Baswani , Mohammad Atif Raza , Kirtikumar Randive","doi":"10.1016/j.geogeo.2025.100383","DOIUrl":"10.1016/j.geogeo.2025.100383","url":null,"abstract":"<div><div>This study presents the first identification of an Alaskan-type intrusion within the late-Proterozoic Padhar mafic-ultramafic complex (PMUC), situated along the Central Indian Tectonic Zone (CITZ). The intrusion exhibits a differentiated composition, including peridotite, pyroxenites, hornblende gabbros and diorite. We adopt an integrated approach that combines field studies with analyses of major oxides, in-situ trace elements, and rare-earth element geochemistry. The field evidences of PMUC displays concentric zoning, with a core of dunite surrounded by wehrlite, olivine clinopyroxenite, clinopyroxenite, hornblende clinopyroxenite, and gabbro akin to Alaskan type intrusions. The primary minerals in the PMUC include olivine (forsterite), pyroxene (Cpx and Opx), amphibole, phlogopite, chromite, and magnetite, while secondary minerals like serpentine, chlorite, and talc are also present. The increase in magnesian number (Mg#) of olivine (70–77), orthopyroxene (53–73), and clinopyroxene (67–88) from mafic to ultramafic units indicates differentiation from a common parent melt. The geochemical signature, including negative Nb and Zr anomalies and positive Rb anomalies, suggests fluid metasomatism from slab sediments. The presence of a hydrous parent magma is inferred from the Mg# of early-formed olivine and high amphibole content. Tectonic discrimination plots of pyroxene and amphibole minerals, combined with <em>in-situ</em> trace element chemistry and bulk rock geochemistry, indicate an arc-related origin. The data suggest fluid-driven subduction zone metasomatism, characteristic of Proterozoic Alaskan-type tectonics within the CITZ. Platinum-group element geochemistry shows a high (Pt + Pd)/(Ir + Ru) ratio, similar to that of intrusive rocks of Alaskan types. Geological and geochemical data further support that the PMUC represents a shallow-level (ca. 17 km) segment of a Proterozoic arc, with minor ultramafic units acting as conduits for arc magma in the Betul Belt.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100383"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.geogeo.2025.100358
Tatyana A. Yasnygina , Sergei V. Rasskazov , Irina S. Chuvashova , Elena V. Saranina
The Ichara Complex of small intrusions is located on the Late Cenozoic Orlov volcanic field of West Sakhalin, in the area of Lamanon Cape. Andesites and dacites of the Ichara Complex and Orlov volcanic field show adakite-like signature (high Sr/Y, low HREE and Y, and high La/Yb) that is associated with magma generation at a crust-mantle transition. Trace element partial melting modelling shows that sources of the adakite-like rocks are the primitive mantle with admixtures of lower crustal (7–12 %) and minor fluid (0.5–1 %) components. Garnet and amphibole contents as well as the degree of partial melting in model sources increase from the older adakite-like andesites of the Orlov volcanic field to the younger andesites and dacites of Ichara Complex. Decreasing 87Sr/86Sr and increasing Sr/Y values from adakite-like andesites to dacites of West Sakhalin correspond to an increasing role of lower crustal and supra-subduction fluid components. The most pronounced adakite-like signature is characteristic of dacites derived from a clinopyroxene-amphibole-garnet source with maximal lower crustal addition. No young slab (MORB-type) material is detected in the modeled sources. In contrast to Ichara adakite-like rocks, the modelling of Daisen adakites from Southwest Honshu yields evidence on melting of the upper part of the Philippine Sea slab with significant contribution of the supra-subduction fluid component.
{"title":"Non-subduction Ichara adakite-like rocks from West Sakhalin (Russian Far East) versus supra-subduction Daisen adakites from SW Japan: Insight from trace-element modelling of sources","authors":"Tatyana A. Yasnygina , Sergei V. Rasskazov , Irina S. Chuvashova , Elena V. Saranina","doi":"10.1016/j.geogeo.2025.100358","DOIUrl":"10.1016/j.geogeo.2025.100358","url":null,"abstract":"<div><div>The Ichara Complex of small intrusions is located on the Late Cenozoic Orlov volcanic field of West Sakhalin, in the area of Lamanon Cape. Andesites and dacites of the Ichara Complex and Orlov volcanic field show adakite-like signature (high Sr/Y, low HREE and Y, and high La/Yb) that is associated with magma generation at a crust-mantle transition. Trace element partial melting modelling shows that sources of the adakite-like rocks are the primitive mantle with admixtures of lower crustal (7–12 %) and minor fluid (0.5–1 %) components. Garnet and amphibole contents as well as the degree of partial melting in model sources increase from the older adakite-like andesites of the Orlov volcanic field to the younger andesites and dacites of Ichara Complex. Decreasing <sup>87</sup>Sr/<sup>86</sup>Sr and increasing Sr/Y values from adakite-like andesites to dacites of West Sakhalin correspond to an increasing role of lower crustal and supra-subduction fluid components. The most pronounced adakite-like signature is characteristic of dacites derived from a clinopyroxene-amphibole-garnet source with maximal lower crustal addition. No young slab (MORB-type) material is detected in the modeled sources. In contrast to Ichara adakite-like rocks, the modelling of Daisen adakites from Southwest Honshu yields evidence on melting of the upper part of the Philippine Sea slab with significant contribution of the supra-subduction fluid component.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100358"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-25DOI: 10.1016/j.geogeo.2025.100469
Wenyue Zhou, Yanyun Sun, Wan Zhang, Guotao Yao, Ruohan Wu
Analysis and research of large complex phenomena before and after the devastating earthquake is of great significance to reduce the threat of natural disasters. Understanding the complex structural deformation of the Longmenshan Fault Zone is essential for elucidating crustal deformation and seismic dynamic mechanisms. This paper analyzes the gravity anomaly distribution characteristics in the Wenchuan Earthquake zone, and subsequently applies edge detection method to invert the pre-earthquake gravity anomalies of the Longmenshan region. The fault distribution characteristics in the Longmenshan region and its adjacent areas before the earthquake have been determined. Besides, morphology difference and possible earthquake formation have been analyzed through the Euler deconvolution results of gravity anomaly profile before and after the earthquake. Finally, a 2-D interactive joint inversion was performed based on the existing seismic and gravity data. The subsurface structure was revealed, and the earthquake formation mechanism was discussed by comparing the underground changes before and after the event.
{"title":"Interpretation of gravity-seismic joint inversion and its application in Longmenshan region","authors":"Wenyue Zhou, Yanyun Sun, Wan Zhang, Guotao Yao, Ruohan Wu","doi":"10.1016/j.geogeo.2025.100469","DOIUrl":"10.1016/j.geogeo.2025.100469","url":null,"abstract":"<div><div>Analysis and research of large complex phenomena before and after the devastating earthquake is of great significance to reduce the threat of natural disasters. Understanding the complex structural deformation of the Longmenshan Fault Zone is essential for elucidating crustal deformation and seismic dynamic mechanisms. This paper analyzes the gravity anomaly distribution characteristics in the Wenchuan Earthquake zone, and subsequently applies edge detection method to invert the pre-earthquake gravity anomalies of the Longmenshan region. The fault distribution characteristics in the Longmenshan region and its adjacent areas before the earthquake have been determined. Besides, morphology difference and possible earthquake formation have been analyzed through the Euler deconvolution results of gravity anomaly profile before and after the earthquake. Finally, a 2-D interactive joint inversion was performed based on the existing seismic and gravity data. The subsurface structure was revealed, and the earthquake formation mechanism was discussed by comparing the underground changes before and after the event.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100469"},"PeriodicalIF":0.0,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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