Geological Journal最新文献

{"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, Zhengle Chen, Taofa Zhou, Wengao Zhang, Fengbin Han, Hailong Huo, Wei Wang, Zechuan Wang, Yitian Luo","doi":"10.1002/gj.5171","DOIUrl":"https://doi.org/10.1002/gj.5171","url":null,"abstract":"<div>\u0000 \u0000 <p>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<i>f</i>(O<sub>2</sub>) values of magma characterised by amphibole and biotite elements vary from −13.1 to −9.1, and H<sub>2</sub>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":"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}

{"title":"The Geological Characteristics of Low-Permeability Sandstone Uranium Deposit in Ordos Basin, North China: Implications of Cause of Low Permeability and Corresponding In Situ Leaching Methods","authors":"Tongpan Wu,&nbsp;Xuebin Su,&nbsp;Lixin Zhao,&nbsp;Chunru Hou,&nbsp;Qingliang Wang,&nbsp;Chunze Zhou,&nbsp;Yuhan Zou,&nbsp;Guoping Jiang","doi":"10.1002/gj.5155","DOIUrl":"https://doi.org/10.1002/gj.5155","url":null,"abstract":"<div>\u0000 \u0000 <p>This study delves into the low-permeability sandstone uranium deposits in China's Ordos Basin, examining the Daying and Bayinqinggeli deposits. Employing x-ray diffraction, clay mineral analysis, x-ray fluorescence, core porosity, gas permeability tests, micrometre computed tomography (CT), and scanning electron microscopy (SEM), the research reveals the low-permeability genesis of these uranium deposits. The findings highlight a high presence of clay minerals, with Daying from 11.5% to 31.5%, and Bayinqinggeli at about 10%. Dense calcareous interlayers are common, with carbonate minerals like calcite and dolomite filling pore spaces and cementing rock-forming minerals, reducing pore sizes and ineffective connectivity, creating dead pore spaces and lowered permeability. The study concludes that the high montmorillonite content and calcareous cementation are the main causes of low permeability, providing a theoretical basis for future permeability enhancement and sustainable exploitation of uranium resources.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1721-1735"},"PeriodicalIF":1.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635553","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":"Integrating GIS, MCDM, and Spatial Analysis for Comprehensive Flood Risk Assessment and Mapping in Uttarakhand, India","authors":"Dhaval R. Maru,&nbsp;Vijendra Kumar,&nbsp;Kul Vaibhav Sharma,&nbsp;Quoc Bao Pham,&nbsp;Anant Patel","doi":"10.1002/gj.5172","DOIUrl":"https://doi.org/10.1002/gj.5172","url":null,"abstract":"<div>\u0000 \u0000 <p>This study presents a comprehensive approach to flood risk assessment and mapping in the Uttarakhand region, India, by integrating geographic information system (GIS) and multi-criteria decision-making (MCDM). The methodology involves using digital elevation models (DEMs) to categorise elevation into five classes, slope analysis to evaluate the role of terrain steepness and drainage density assessment to identify areas less susceptible to flooding. Average annual rainfall data, classified from meteorological stations, land use/land cover patterns and distances from rivers and roads, were analysed within a GIS framework to assess flood susceptibility. The analytic hierarchy process (AHP) was employed to assign weights to these criteria and generate a flood risk index (FRI) map. Key findings indicate that extensive moderate-to-high-risk zones are present, particularly in the lower regions of Uttarakhand. The weighted overlay analysis using GIS and AHP effectively identified areas at greater risk of flooding. The results offer valuable insights for flood risk management, land-use planning and disaster preparedness, highlighting the need for targeted interventions to enhance flood resilience in the region.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 9","pages":"2263-2280"},"PeriodicalIF":2.2,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145013303","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":"Chinese Digital Economy and Urban Green Innovation Quality and Efficiency: The Threshold Effect Analysis Based on Chinese Cities Agglomeration","authors":"Li Yue,&nbsp;Yuan Yin,&nbsp;Yuxuan Cao,&nbsp;Fayyaz Ahmad","doi":"10.1002/gj.5168","DOIUrl":"https://doi.org/10.1002/gj.5168","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper takes 277 Chinese cities data from 2011 to 2020 and measures the quality of green innovation and efficiency of green innovation based on super-efficiency SBM model. This paper uses the fixed effect model to analyse the digital economy on the influence of the quality and efficiency of urban green innovation, and uses the threshold effect model to test the threshold effect gathered in this effect. This paper found that the digital economy can promote urban green innovation quality and efficiency. The conclusion is still valid after robustness tests, such as recalculating the level of the digital economy and adjusting the sample time interval. Heterogeneity test shows that digital economy has a more obvious effect on improving the quality of green innovation in central and western cities, non-resource cities, cities with high-level innovation and cities with low-level enterprise density, while it has a more obvious effect on improving the efficiency of green innovation in eastern cities, non-resource cities, cities with high-level innovation and cities with high-level enterprise density. Furthermore, digital economy can enhance the quality and efficiency of urban green innovation by increasing the degree of urban economic agglomeration, talent agglomeration, industrial agglomeration and financial agglomeration. Additionally, the quality of green innovation, the improvement effect of the digital economy is stronger when the degree of economic agglomeration exceeds the threshold. Finally, when the degree of economic and financial agglomeration exceeds the threshold, the improvement of green innovation efficiency caused by the digital economy is stronger. Therefore, the government should improve the infrastructure of the digital economy, pay attention to the role of agglomeration, develop the digital economy according to local conditions and promote urban green innovation.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 9","pages":"2195-2212"},"PeriodicalIF":2.2,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145013186","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":"Geospatial Assessment and Mapping Landslide Susceptibility for the Garo Hills Division, Meghalaya, India","authors":"Naveen Badavath,&nbsp;Smrutirekha Sahoo","doi":"10.1002/gj.5166","DOIUrl":"https://doi.org/10.1002/gj.5166","url":null,"abstract":"<div>\u0000 \u0000 <p>Creating accurate and effective Landslide Susceptibility (LS) maps can aid disaster prevention and mitigation efforts and provide sufficient public safety. The primary aim of this study is to develop an LS map for the Garo Hills region in Meghalaya, India, using the weight of evidence (WoE), frequency ratio (FR), and Shannon entropy (SE) methods. A comprehensive landslide inventory catalogued 98 events from 2000 to 2023 for the analysis, and nine key geographical and environmental parameters were prepared. Conducted multicollinearity and correlation analysis to identify and mitigate collinearity issues between factors. The model's performance was analysed through the area under the curve (AUC) value of receiver operating characteristic (ROC) curves and three recent landslides. The results showed that FR method achieved the highest accuracy, with successive rate curve (SRC) AUC and predictive rate curve (PRC) AUC values of 0.860 and 0.940, respectively, and classified susceptibility at three sites as high, moderate, and low. The WoE method effectively identified three landslides site in high and very high susceptibility zones, achieving SRC AUC and PRC AUC values of 0.844 and 0.915, respectively. The SE method showed robust performance in predicting landslide-prone areas, with PRC AUC comparable to other methods (0.913), though its SRC AUC (0.771) was lower. Developed maps revealed that high and very high susceptibility zones account for approximately 10% and 3% of the study area, predominantly near roads, steep slopes, and higher elevations. The information in this study is valuable for civilians and the government authorities involved in hazard monitoring and management.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 5","pages":"1184-1201"},"PeriodicalIF":1.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914727","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":"Geochemistry, Geochronology and Petrogenesis of the Proterozoic Betul–Chhindwara Bimodal Volcanics: Constraints on the Evolution of the Central Indian Tectonic Zone, Central Indian Shield","authors":"Ibrahim Yousuf,&nbsp;Talat Ahmad,&nbsp;D. V. Subba Rao,&nbsp;Roohi Irshad,&nbsp;S. Balakrishnan","doi":"10.1002/gj.5154","DOIUrl":"https://doi.org/10.1002/gj.5154","url":null,"abstract":"<div>\u0000 \u0000 <p>The Central Indian Tectonic Zone (CITZ) runs across peninsular India and includes Proterozoic bimodal volcanics (basalt-rhyolite), quartzite, mafic-ultramafic rocks, volcanic sediments and Banded Iron Formation (BIF). The bimodal volcanic rocks of Betul–Chhindwara belt have been subjected to upper greenschist to lower amphibolite-grade metamorphism and have well-preserved remnants of pillow structures. Total alkali vs. silica diagram clearly discriminates all the samples into subalkaline basalts and rhyolites which corresponds to their bimodal nature. Mafic volcanic sequence of Betul–Chhindwara belt is represented by high Ti and low Ti Groups. I. High Ti basalt has undergone low degree of partial melting (~5%), whereas low Ti basalt has undergone a high degree of partial melting (~20%) of the same source rock. Fe and Ca decrease with decreasing Ti indicating clinopyroxene and iron-titanium oxide fractionation in both the groups of basalt. These basalts are generally enriched in incompatible trace elements such as Rb and Ba and depleted in Nb, P and Ti, which collectively are good indicators of continental crust/lithosphere involvement in their genesis. The basalts show no Eu anomaly, which indicates little role of plagioclase during fractionation process. Positive anomalies of U–Th–Zr for the basalts indicate crustal involvement. Whole-rock Sm–Nd isochrons for the mafic volcanic rocks indicate an age of crystallisation for these volcanic rocks at about 1232 ± 37 Ma (initial ¹⁴³Nd/¹⁴⁴Nd = 0.510752 ± 0.000035, mean square weighted deviate [MSWD] = 1.20) which is much younger than the basement rocks ca. 1500 Ma. The <i>ε</i>\u0000 _{Nd<i>t</i>\u0000} (<i>t</i> = 1232 Ma) vary from −5.93 to −3.1 for the mafic volcanic rocks and between −5.81 and +0.14 for felsic volcanic rocks. Depleted mantle model ages of basalts vary from 2204 to 3040 Ma, and for rhyolites, these vary from 2174 to 2863 Ma, respectively. The <i>ε</i>\u0000 _Nd value for all the basaltic samples includes both the groups of basalts plot away from the CHUR line indicating their derivation from a depleted source and evolves to lower values, indicating longer crustal residence or more crustal contribution. Mafic magma might have been produced at the subduction zone interacted with the lower continental crust while ascending to the surface. This lowered the melting point of the continental crust which led to the production of felsic melt. Episodic mafic magma could have led to the production of rhyolite, produced at different levels of the continental crust.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1701-1720"},"PeriodicalIF":1.4,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635300","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":"Study on the Physical, Chemical and Radioactive Gas—Radon (222Rn) Exhalation Properties of Bleached Sandstone in the Northeast Edge of the Ordos Basin","authors":"Xin Hu,&nbsp;Qiang Sun,&nbsp;Jiakun Wu,&nbsp;Shaoni Wei,&nbsp;Beichen Du,&nbsp;Xiaoying Ding,&nbsp;Jishi Geng","doi":"10.1002/gj.5157","DOIUrl":"https://doi.org/10.1002/gj.5157","url":null,"abstract":"<div>\u0000 \u0000 <p>The northeast margin of Ordos Basin, China has a large area with ‘bleached sandstone’, a unique rock characterised by a low diagenetic degree and poor cementation degree. Long-term wind and hydraulic erosion have led to significant soil erosion, vegetation degradation and low ecological carrying capacity in this region, with huge amounts of sediments being transported to the Yellow River. Therefore, it is critical to investigate the weathering mechanism and physicochemical characteristics of bleached sandstone. In this study, the pore structure, elemental composition, mineral composition and radon exhalation characteristics of the bleached sandstone were analysed using low-temperature nitrogen adsorption instrument, inductively coupled plasma mass spectrometer, polarising microscope and environmental radon detector, respectively. Moreover, the physicochemical characteristics of the bleached sandstone were analysed to determine the correlation among them. The results demonstrated that the degree of pore development in bleached sandstone is significantly higher than that in original rock, and the content of mesopores of size from 2 to 50 nm is the highest. These pores were found to be predominantly slit pores with parallel plate structure. The mineral composition is primarily quartz, feldspar, clay minerals and muscovite, with quartz being the highest. Quartz and feldspar exhibited significant weathering, broken crystals and more impurities. A large amount of biotite was altered to form muscovite. The intergranular spaces of bleached sandstone are filled with heterobase, primarily composed of clay minerals. Additionally, clay minerals formed a ring band structure around the particle skeleton. Bleached sandstone was found to be rich in P, Ba, Mn, Sr, Zr and other elements, with Ba showing the highest proportion. The bleached sandstone is enriched in toxic elements Be, As, Cd, Sb, Hg, Tl and ²³⁸U compared with the original rock, indicating that the latter has a certain degree of adsorption. Among them, Be has the highest enrichment degree. Moreover, it is enriched with light rare earth and deficient in heavy rare earth. δEu and δCe exhibit a slight deficiency. Although the rate of radon exhalation in bleached sandstone is low, it is higher than that of the original rock. The high porosity and micropore content can promote radon exhalation. High ²³⁸U content can enhance radon generation, which exhibited a positive correlation with radon exhalation rate. The research results can provide a reference for ecological management, development and utilisation of bleached sandstone in this region.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1736-1753"},"PeriodicalIF":1.4,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635301","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}