Geological Journal最新文献

{"title":"A Revolutionary Hybridised MCDM Approach on Geographic Information System for Evaluation of Flood Risk in Subarnarekha River Basin, India","authors":"Sipra Mophapatra,&nbsp;Dillip Kumar Ghose,&nbsp;Deba Prakash Satapathy","doi":"10.1002/gj.5196","DOIUrl":"https://doi.org/10.1002/gj.5196","url":null,"abstract":"<div>\u0000 \u0000 <p>Determining and characterising locations vulnerable to flooding can help in reducing damage and the number of fatalities. During the monsoon season, East India's Subarnarekha River frequently floods to a significant degree. In current work, we suggest a unique hybrid strategy for preparing the entire catchment's Flood Susceptibility Mapping (FSM). The study area's FSM was conducted by considering 10 flood conditioning factors utilising the Best-Worst Method (BWM) and a multi-parametric Analytical Hierarchy Process (AHP) as per expert knowledge. Meanwhile, the proposed strategy incorporates a Decision Making Trial and Evaluation Laboratory (DEMATEL) for examining causal linkages and dependencies between different elements affecting the flooding process. Several statistical matrices were used to compare the suggested strategy of BWM and AHP. Based on our findings, we concluded that the integration of DEMATEL with AHP and BWM (ID BWM, ID AHP) was more effective than alternative strategies. The findings show that out of 10 flood conditioning factors, slope, elevation, distance from the river, drainage density, Topographic wetness Index (TWI), Land Use Land Cover (LULC), Normalised Difference Vegetation Index (NDVI), precipitation, soil texture, and curvature, factors that have the biggest effects on the local flooding phenomenon are elevation, slope, precipitation, and distance from the river. For validating the efficacy of the flood susceptibility map, Area under the Receiver Operating Characteristic Curve (AUC-ROC) was adopted and demonstrated, showing a pretty high accuracy of (0.92 or 92% and 0.94 or 94%) for ID AHP and ID BWM, respectively. Our research findings provide a highly affordable and useful answer to the flooding problems of basin Subarnarekha.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 5","pages":"1046-1064"},"PeriodicalIF":1.4,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utilising Machine Learning Approaches for Enhanced Landslide Susceptibility Mapping in Sikkim, India","authors":"Sujit Kumar Roy,&nbsp;Sumon Dey,&nbsp;Jayanta Das,&nbsp;Billal Hossen,&nbsp;Swarup Das,&nbsp;Md. Mahmudul Hasan,&nbsp;Pratik Mojumder","doi":"10.1002/gj.5198","DOIUrl":"https://doi.org/10.1002/gj.5198","url":null,"abstract":"<div>\u0000 \u0000 <p>Landslides pose significant hazards in the mountainous region of Sikkim, India, necessitating accurate susceptibility mapping to mitigate risks. This study applies four machine learning models: Boosted Tree (BT), Gradient Boosting Machine (GBM), K-Nearest Neighbour (KNN), and Multilayer Perceptron (MLP) to develop a detailed landslide susceptibility map. Feature selection was performed using correlation analysis, the Boruta model, and multicollinearity tests, which identified 13 key landslide conditioning factors based on 1456 landslide inventory points. The GBM model demonstrated the highest predictive performance with an AUC of 0.99, followed by BT (AUC: 0.965), MLP (AUC: 0.940), and KNN (AUC: 0.895) in the testing dataset. The confusion matrix validation confirmed that GBM outperformed other models, achieving the highest F1 score (0.894) and accuracy (89.4%), followed by BT with an F1 score of 0.874 and accuracy of 87.8%. KNN and MLP displayed lower performance, with KNN showing an F1 score of 0.724 and accuracy of 72.6%, and MLP significantly underperforming with an F1 score of 0.096 and accuracy of 48.6%. Statistical significance testing using the Wilcoxon Signed-Rank Test revealed significant differences between BT and MLP (<i>p</i> = 0.018), while other model pairs exhibited no statistically significant performance differences. Additionally, the variable importance analysis highlighted Diurnal Temperature Range (DTR) as the most critical factor influencing landslide occurrence (43.99%), followed by elevation (21.59%). These findings provide valuable insights for policymakers and government authorities, enabling them to take necessary measures for effective landslide management in the vulnerable areas of Sikkim, confirming the efficacy of machine learning models for geohazard assessments.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 5","pages":"1150-1169"},"PeriodicalIF":1.4,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrological and Geochemical Research on the Telaaobao Sandstone–Hosted Uranium Deposit in the North-Western Ordos Basin, China: Implications of Multiple Sources","authors":"Xiao-Wen Hu,&nbsp;Ming-Xing Ling,&nbsp;Jian-Bing Xu,&nbsp;Qiang Wei,&nbsp;Xiao-Yong Yang,&nbsp;Chao Lu,&nbsp;Long-Hui Wang,&nbsp;Feng Zhang,&nbsp;Xiao-Jie Jiang,&nbsp;Zhuang Zhao","doi":"10.1002/gj.5200","DOIUrl":"https://doi.org/10.1002/gj.5200","url":null,"abstract":"<div>\u0000 \u0000 <p>The newly discovered Telaaobao uranium deposit, hosted within Lower Cretaceous sandstones in the north-western Ordos Basin, represents a significant new stratigraphic target for uranium exploration. This study offers detailed petrological and geochemical analyses of different types of rocks from the Huanhe Formation, aiming to investigate the factors controlling uranium mineralisation in this deposit. The Huanhe Formation is generally characterised by low to moderate concentrations of total rare earth element (∑REE) (70–213 ppm) and Y (7.5–30.1 ppm), right-inclined REE patterns and slightly negative Eu anomalies, which resemble those of the upper continental crust (UCC). The trace element characteristics further reveal that the sedimentary sources have an average composition typical of intermediate-felsic rocks, with the addition of some old sediments. The U content in sediments is mostly higher than that of the average UCC, even in non-mineralised rocks from both the oxidised (2.5–58.8 ppm) and reduced zones (2.0–49.6 ppm), indicating that the provenance rocks and the sedimentary strata can serve as enriched uranium sources for the deposit. The Lower Cretaceous strata in the north-west margin of the Ordos Basin, which were formed in an arid depositional environment and lacked organic matter and other reducing agents, restricted the formation of uranium deposits. Nevertheless, influenced by multiple stages of tectonic activity, the release of deep-seated reducing fluids, such as oil and gas, greatly enhanced the reducing capacity of the sandstone, creating an extensive green reduction zone. The current development of uranium ore bodies is mainly controlled by the oxidation–reduction transition zone. Additionally, high U (591–4080 ppm) enrichment has also been found in the oxidised zone, where mineralised rocks display distinct petrological and geochemical characteristics from those in the transition zone. These rocks exhibit anomalous increases in REEs (∑REE = 168–722 ppm), with bell or flat shape REE patterns and high Y concentration (147–866 ppm). These features resemble the uranium minerals that are typically formed in deep-originated hydrothermal fluids, especially in unconformity-related uranium deposits. In this case, the hydrothermal fluids may have also introduced uranium into the Telaaobao deposit as a potential source.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 8","pages":"1909-1927"},"PeriodicalIF":2.2,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144814583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long Term and Short Term Spatio-Temporal Characterisation of Rainfall Variability and Dynamicity Over the Westernmost Part of West Bengal, India Using Modified Mann-Kendal Test and Innovative Trend Analysis","authors":"Suman Mukherjee,&nbsp;Edris Alam,&nbsp;Manas Mondal,&nbsp;Subrata Haldar,&nbsp;Subhasis Bhattacharya,&nbsp;Md Kamrul Islam,&nbsp;Suman Paul","doi":"10.1002/gj.5187","DOIUrl":"https://doi.org/10.1002/gj.5187","url":null,"abstract":"<div>\u0000 \u0000 <p>It has become important to understand the dynamic nature of hydro-meteorological phenomena, especially rainfall, as rainfall is considered to be the principal source of water in the hydrological cycle. Purulia, the westernmost district of West Bengal, India, is part of the Chotanagpur Plateau fringe with its undulating topography, varying slope, hard rock aquifer, limited surface and subsurface water resources, and sub-humid dry climate. Drought has been a recurring phenomenon for years, and the majority of its residents practise rain-fed agriculture, solely relying on the monsoonal rain. Therefore, it is crucial to study the nature and pattern of annual and seasonal rainfall. The objective of the study is to bring out the long-term nature of the rainfall trend along with the short term and to understand the characteristics of the rainfall over the region. This study has used the India Meteorological Department (IMD) provided daily gridded rainfall dataset for 1961 to 2020, non-parametric Mann-Kendal (M-K) test, Modified version of M-K test, and Sen's slope estimator to determine the trend of rainfall in long-term and short-term time series; the recently developed approach, i.e., innovative trend analysis (ITA) is also applied to determine the underlying trend and its stability in the long-term time series. For the purpose of change point identification, this paper has applied the sequential version of M-K test (SQMK). Both the long term (1961–2020) and two short term (1961–1990 and 1991–2020) time series have been analysed annually and seasonally. To understand the long-term variation in the character of rainfall temporally and spatially, three indices, i.e., precipitation concentration index (PCI), rainfall deviation index (RDI) and modified Fournier index (MFI) have also been implemented. The ITA approach provides a better understanding of the trend as it can determine the trend whilst the M-K test failed to determine it in some cases. In contrast to the long-term (1961–2020) and first-half (1961–1990) series, the second half of the time step (1991–2020) had the largest falling trend; i.e., 90% of the total stations have recorded a downward trend during the monsoon season. PCI and RDI, as well as SSE, identified the western half of the district as being the driest, and MFI revealed that the eastern section of the district has high rainfall intensity. This study may help the planners and policymakers to frame policies for its people and their livelihood; the comprehension of the previous hints will be used to predict the future.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 5","pages":"1065-1092"},"PeriodicalIF":1.4,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Neoproterozoic Mafic Dykes in the South Qinling Belt, China: Geochemistry, Zircon Ages and Tectonic Implications","authors":"Tong Li,&nbsp;Chao Wang,&nbsp;Xiao-ying Liao,&nbsp;Liang Liu","doi":"10.1002/gj.5158","DOIUrl":"https://doi.org/10.1002/gj.5158","url":null,"abstract":"<div>\u0000 \u0000 <p>The mafic magmatism during the Middle-late Early Neoproterozoic period (ca. 830–720 Ma) is frequently construed as indicative of plume magmatism, facilitating the breakup of the supercontinent Rodinia and establishing a climatic backdrop conducive to the onset of the Sturtian glaciation. Nevertheless, the tectonic models proposed to explain the formation of the latest Tonian magmatism in the Yangtze Block remain a subject of debate. In this study, four mafic dyke samples yielded weighted mean ²⁰⁶Pb/²³⁸U ages of 733 ± 14 Ma, 722 ± 8 Ma and 734 ± 6 Ma, 733 ± 5 Ma, respectively, indicating their crystallisation age in the Neoproterozoic era. These mafic dykes are characterised by a subalkaline tholeiitic composition, with relatively low concentrations of SiO₂ (43.04–46.75 wt%) and MgO (5.50–7.86 wt%), and Mg^# values ranging from 48 to 64. Furthermore, the mafic dykes are also marked by relatively high FeO^T (9.26–12.28 wt%), TiO₂ (1.20–1.62 wt%). They exhibit a slight enrichment in LREE with (La/Yb)_N ratios of 2.99–3.35 and demonstrate trace element patterns that are typical of continental tholeiite. Moreover, the mafic dykes display εNd (t) values ranging from −3.7 to +4.4, εHf(t) values ranging from −12.33 to 4.41, along with low ratios of (²⁰⁶Pb/²⁰⁴Pb)_i (16.70–17.46), (²⁰⁷Pb/²⁰⁴Pb)_i (15.37–15.70) and (²⁰⁸Pb/²⁰⁴Pb)_i (36.67–38.00). The combination of these characteristics and clinopyroxene compositions provides evidence that the source region of the mafic dykes was created through the partial melting of the depleted asthenosphere mantle mixed with subduction fluid metasomatic lithospheric mantle during the transition of the spinel-garnet facies peridotite within an extensional setting. The congruities in formation chronology, petrogenesis, source attributes and tectonic settings among the mafic rock samples within the Douling Complex, the Yaolinghe Group and the Wudang Block suggest that the South Qinling Belt was in an extension setting during the Middle-late Early Neoproterozoic, and presumably witnessed the rifting of the Rodinia supercontinent.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1754-1770"},"PeriodicalIF":1.4,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exhumation Degree of Intrusions in the Kangguer–Huangshan Area and Its Constraint on Ore-Preservation in the Jueluotage Tectonic Belt, Eastern Tianshan","authors":"Jilin Li,&nbsp;Zhengle Chen,&nbsp;Taofa Zhou,&nbsp;Wengao Zhang,&nbsp;Fengbin Han,&nbsp;Hailong Huo,&nbsp;Wei Wang,&nbsp;Zechuan Wang,&nbsp;Yitian Luo","doi":"10.1002/gj.5171","DOIUrl":"https://doi.org/10.1002/gj.5171","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;The Kangguer–Huangshan ductile shear zone lies in the Eastern Tianshan area, southeast of the Central Asian Orogenic Belt (CAOB), it is a complex and strong tectonic deformation zone that is oriented from east to west. The area in Northwest China contains important polymetallic mineral resources, with intensive structural and magmatic activities, superior ore-forming geological conditions, especially porphyry copper deposits, ductile shear-type gold deposits, Cu–Ni sulfide deposits, etc. In this work, the intermediate–acid intrusive rocks in the Kangguer–Huangshan ductile shear zone are used as the research objects, and detailed petrographic observations and electron microprobe analysis (EMPA) of the chemical compositions of amphibole and biotite are carried out to determine the temperature and pressure conditions, the oxygen fugacity and water content during magmatic emplacement and to calculate the emplacement depth of intrusive rocks to estimate the metallogenic potential of polymetallic deposits in the area. Apatite fission track (AFT) thermochronology have been conducted to obtain information about the uplift–exhumation history in the Kangguer–Huangshan area since the Mesozoic–Cenozoic. Combined with the mineralisation depth of typical deposits in the area, the constraints of the uplift–exhumation degree on the post-ore modification and preservation of deposits in the area are analysed. The crystallisation temperatures of the amphiboles and biotites are 665.1°C–919.5°C, the crystallisation pressures are 85.2–355.2 MPa, corresponding the magma emplacement depths are 2.4–10.9 km. The oxygen fugacity log&lt;i&gt;f&lt;/i&gt;(O&lt;sub&gt;2&lt;/sub&gt;) values of magma characterised by amphibole and biotite elements vary from −13.1 to −9.1, and H&lt;sub&gt;2&lt;/sub&gt;O in coexisting melts is greater when amphiboles crystallised. Apatite fission track analysis performed on 10 samples from 8 granites in the area reveals that the apatite fission track pooled ages of granitoids from the Kangguer–Huangshan ductile shear zone range from 120 ± 9 to 55 ± 4 Ma, with mean track lengths varying from 11.5 ± 1.9 to 13.0 ± 1.9 μm. Further temperature–time modelling of the fission tracks indicates that there exists two exhumation events in the Kangguer–Huangshan ductile shear zone that occurred mainly in the Cretaceous (120–60 Ma) and Miocene (20–0 Ma). The Meso–Cenozoic exhumation and rates in this area are calculated by the best fitting line, and the values are 3.1–4.0 km and 0.013–0.032 mm/a, respectively. A comparison of the emplacement depth and exhumation depth of granites with the regional metallogenic depth reveals that the Permian Cu–Ni sulfide deposits with deep mineralisation, while little regional tectonic uplift influence for the orebodies, and that most of the orebodies are still preserved in deep underground and have great potential for prospecting. The metallogenic depth of porphyry Cu (Mo) deposits is similar to the emplacement depth of the granitoids","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 9","pages":"2232-2262"},"PeriodicalIF":2.2,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145013259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Palaeozoic Tectonic Evolution of the Northern Part of the Zhusileng-Hangwula Arc in the Middle Segment of the Central Asian Orogenic Belt: Insights From Structural Geology and Geochronology","authors":"Xiao Cui,&nbsp;Genhou Wang,&nbsp;Shouting Zhang,&nbsp;Jonathan Atuquaye Quaye,&nbsp;Dewen Liu,&nbsp;Xi Gao,&nbsp;Dian Li,&nbsp;Yuanku Meng","doi":"10.1002/gj.5174","DOIUrl":"https://doi.org/10.1002/gj.5174","url":null,"abstract":"<div>\u0000 \u0000 <p>The final closure time and tectonic evolution of the middle segment of the Paleo-Asian Ocean (PAO) remain poorly constrained. The northern part of the Zhusileng-Hangwula arc, located in the middle segment of the Central Asian Orogenic Belt, is crucial for understanding its tectonic evolution and for constraining the closure time of the middle segment of the PAO. Field structural, microstructural, and fabric analyses reveal that the NE-trending ductile shear zone within the Baishan Formation has undergone sinistral shearing. Zircon U–Pb and ³⁹Ar/⁴⁰Ar dating indicate that the shear zones formed at 216 Ma. In addition, the northern part of the Zhusileng-Hangwula arc experienced superimposed folding deformation. Kinematic studies show that the second phase of folding refolded the tightly upright NE-trending F1 folds into NE-trending asymmetric steeply plunging F2 folds under a sinistral transpression regime. ⁴⁰Ar/³⁹Ar geochronology data indicate that the first phase of folding deformation occurred at 215 Ma, while the second phase of folding deformation occurred slightly later than 215 Ma. Geochemical characteristics indicate that the Baishan Formation formed in an active magmatic arc setting during the Late Permian. Combined with published data, the final closure time of the northern part of the Yagan and Zhusileng-Hangwula arcs in the middle segment of the PAO can be constrained to the Late Permian–Early Triassic. The formation of the shear zones and the superimposed folding deformation can be attributed to the oblique convergence orogenic process between the South Gobi Zone and the Yagan and Zhusileng-Hangwula arcs during the Late Triassic.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 9","pages":"2311-2327"},"PeriodicalIF":2.2,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Novel Source–Sink Matching Optimization Model for Carbon Capture and Storage","authors":"Chun-sheng Gu,&nbsp;Chang-kun Zhu,&nbsp;Xulong Gong,&nbsp;Shugang Xu,&nbsp;Qi-qi Zhang,&nbsp;Longyu Cui,&nbsp;Yi Lu,&nbsp;Manlin Wang","doi":"10.1002/gj.5178","DOIUrl":"https://doi.org/10.1002/gj.5178","url":null,"abstract":"<div>\u0000 \u0000 <p>In carbon capture and storage system (CCS), the task of the CO₂ source–sink matching involves optimising source–sink cluster deployment, transportation path, and pipe network layouts. This task is an integral aspect of the CCS commercialization process and constitutes a combinatorial optimization problem aimed at achieving low cost and maximum storage capacity within the system. Here, a novel mathematical model of source–sink matching combinatorial optimization is established. (1) The model can account for various factors, including the lifespan of the source–sink, the capture (injection) rate of CO₂ sources (sinks), and the duration of the CCS system. The objective aimed to maximise CO₂ storage capacity while minimising transportation costs over the entire operational period. Additionally, based on genetic algorithm, a rapid solution approach was introduced to address the objective. (2) A comparative study was conducted through existing cases. The results show that, compared to the Pinch analysis method, the newly constructed optimization model in Case 1 can increase the total storage of the system by 4.6%. Similarly, the results of Case 2 demonstrate that the matching results of the new model can increase the total storage by 13.3%. (3) Through Case 3, the model provides a preferred but not unique matching scheme, which meets the criteria of maximising storage while minimising transportation costs at any given time. Finally, the practicability and reliability of the novel model were verified through the cases. The model can provide a framework for the development of source–sink matching decision system and CCS planning.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 8","pages":"1840-1851"},"PeriodicalIF":2.2,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144815114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleoenvironmental Shifts Across the Upper Cretaceous-Palaeocene Succession in Eastern Tethys, Pakistan","authors":"Amir Shahzad,&nbsp;Thierry Adatte","doi":"10.1002/gj.5173","DOIUrl":"https://doi.org/10.1002/gj.5173","url":null,"abstract":"<div>\u0000 \u0000 <p>The Cretaceous-Paleogene (K/Pg) transition is a global mass extinction event that affected the paleoenvironment, palaeogeography, and biota of the Earth. In this study, we investigated the sedimentary record of the K/Pg transition in the Hazara Basin, a part of Eastern Tethys in Pakistan, using an integrated approach of sedimentology, micropaleontology, geochemistry, and mineralogy. We identified eight biozones based on benthic and planktonic foraminifera, ranging from Middle Cenomanian to Thanetian in age. We also recognised 10 microfacies, reflecting different depositional settings from middle-outer ramp to inner ramp and shoreface environments across the K/Pg transition. We used geochemical proxies and indices to infer the paleoredox conditions, paleosalinity, paleotemperature, detrital input, and paleoproductivity of the basin. We found that oxygenated conditions prevailed across the K/Pg transition, with normal salinity in marine settings and lower salinity in continental settings. The Sr/Ca and Mn/Ca ratios indicated moderate paleotemperature and low terrigenous input, except for shale intervals with higher detrital input. The chemical weathering proxies showed moderate to intense weathering in the source area. The organic matter was mainly of type-III and type-IV, with low total organic carbon and hydrogen index values. The clay mineralogy was dominated by kaolinite, indicating warm and humid conditions, followed by smectite, chlorite, and illite. The K/Pg boundary could not be constrained by the fossil record due to the absence of Late Maastrichtian and Danian fauna in the Hazara region, which may be attributed to tectonic uplift, erosion, and non-deposition of sediments during the collision of the Indian Plate and Kohistan Island Arc. However, the boundary could be recognised by the facies change corresponding to lateritic and oolitic haematite at the base of the early Palaeocene Hangu Formation.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 9","pages":"2281-2310"},"PeriodicalIF":2.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145013067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Characteristics and 1-D Basin Modelling Study of the Early Cretaceous and Paleogene Succession in the Southern Indus Basin, Southern Pakistan","authors":"Adeeb Ahmed,&nbsp;Mohammed Hail Hakimi,&nbsp;Samina Jahandad,&nbsp;Aref Lashin,&nbsp;Afikah Rahim,&nbsp;Waqas Naseem,&nbsp;Danis K. Nurgaliev,&nbsp;Muhammad Asif Khan,&nbsp;Muhammad Nofal Munir","doi":"10.1002/gj.5169","DOIUrl":"https://doi.org/10.1002/gj.5169","url":null,"abstract":"<div>\u0000 \u0000 <p>Early Cretaceous and Paleogene shale and limestone sediments in the southern Indus Basin were investigated by geochemical data and 1-D basin modelling. Most of the shales from the Early Cretaceous and Paleogene formations exhibit total organic carbon (TOC) content between 0.51 wt. % and 6.06 wt. %, overall, indicating organic matter richness capable of generating hydrocarbons. However, the limestone samples of the Paleogene formations have lower TOC values in the range of 0.36–0.97 wt.%, inferring poor to fair petroleum source rock. The studied shale and limestone sections exhibit also varying hydrogen indices (HI) ranging from 27 to 430 mg HC/g TOC and different kerogen pathways, ranging from Type II to Type IV. Generally, most of the samples with the Lower Cretaceous and Paleogene formations consist mainly of hydrogen-poor Type III and IV kerogens, with HI values range from 27 to 206 mg HC/g TOC, while some other samples belonging to the Paleogene formations exhibit Types II and II/III kerogen (HI from 219 to 430 mg HC/g TOC). The dominance of such kerogen shows the presence of oil- and gas-prone source rocks, with high potential for gas generation. Maturity-related indicator of Rock-Eval T_max shows different thermal maturity levels, ranging from immature to post-mature. Most of the Lower Cretaceous Goru shales are more mature than other Paleogene sediments, and rank from main oil to gas generation windows, reaching the generation efficiency. This is probably attributed to the deep burial of the Goru Formation reaching a depth up to 4050 m. Therefore, the preliminary geochemical results of the Goru shale unit were integrated into a basin modelling analysis using three exploratory wells to simulate the timing of oil and gas generation. In this case, the simulated basin models reveal that the Goru source rock system currently attained the main oil and gas generation windows, with computed vitrinite reflectance values between 0.75 and 2.00 Easy %Ro. The simulated models indicate that commercial amounts of oil have been generated from the Goru source rock system since the early Palaeocene, as demonstrated by the TR ratio of up to 62%. Moreover, oil was cracked into thermogenic gas during the late Eocene to present-day, with computed vitrinite reflectance of up to 2.00 Easy %Ro. The oil and gas generation was increased with increasing the burial depth, thus, an intensive hydrocarbon exploration and production program is highly recommended in the deeper stratigraphic succession of the Goru source rock system in the southern Indus Basin.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 9","pages":"2213-2231"},"PeriodicalIF":2.2,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}