Geological Journal最新文献

{"title":"Early Cretaceous Tuffs From the Southwestern Ordos Basin, North China Craton: Geochronology, Geochemistry and Geological Significance","authors":"Yin Chen,&nbsp;Jianguo Li,&nbsp;Lulu Chen,&nbsp;Bo Zhang,&nbsp;Hualei Zhao","doi":"10.1002/gj.5143","DOIUrl":"https://doi.org/10.1002/gj.5143","url":null,"abstract":"<div>\u0000 \u0000 <p>Tuffs are the significant medium to figure out volcanic activities, explore regional tectonic evolution and constrain the depositional ages in basins. Tuff intervals are found in the Early Cretaceous successions from the southwestern Ordos Basin, southwestern part of the North China Craton, which supplies new geochronological and geochemical evidence to understand the Early Cretaceous tectonic setting. In this work, whole-rock and zircon geochemistry, zircon U–Pb dating and Hf isotopic analyses were conducted. Zircon U–Pb dating results yielded ages of 125.32, 121.71 and 118.20 Ma, which have recorded the erupting of rhyolites and constrained the depositional age precisely to belong to the Aptian. Two groups of zircons Hf isotopic data are ε_Hf(t) of 8 with T_DM2 of 693–570 Ma and ε_Hf(t) of −11.7 with T_DM2 of 1908 Ma. Westerlies or southwesterlies were prevailing in the Early Cretaceous and can bring cinerites from the western or southwestern part of China. Comparative analysis of geochemistry and zircon Hf isotopes exhibited that the volcanoes from the Qiangtang Block and the Qingling Orogen were the most potential sources for the tuffs. These Early Cretaceous volcanic eruptions were triggered by the subduction of the Bangong-Nujiang Ocean and the Paleo-Pacific Ocean with plate roll-back and lithospheric destruction.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1559-1575"},"PeriodicalIF":1.4,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635602","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 Triassic to Jurassic Tectonic Evolution of the Northern Sichuan Foreland Basin, South China Craton","authors":"Can Xiong,&nbsp;Xiangyang Yang,&nbsp;Yunpeng Dong,&nbsp;Ming Xiao,&nbsp;Zhaoying Wei,&nbsp;Yanbo Feng,&nbsp;Jiaopeng Sun,&nbsp;Lingzi Xiang,&nbsp;Lin Yu,&nbsp;Songlin Xie,&nbsp;Cuifang Wang,&nbsp;Songlin Zhang","doi":"10.1002/gj.5131","DOIUrl":"https://doi.org/10.1002/gj.5131","url":null,"abstract":"<div>\u0000 \u0000 <p>The Northern Sichuan Foreland Basin, which is located in the northwest of South China Craton (SCC), was formed by the intracontinental thrusting between the Qinling Orogenic Belt (QOB) and SCC. The Upper Triassic to Jurassic sedimentary successions within this foreland basin, contain crucial information for revealing the intracontinental deformation sequence between the QOB and the SCC. In this study, based on a systematic dataset, including the palaeocurrent orientation, sandstone modal composition, and detrital zircons U–Pb age data, we attempt to reveal the tectonic processes during the Late Triassic to Jurassic interval. The palaeocurrent orientations, which is primarily directed in the southward and northwestward directions, indicate that the sediments were sourced from the north and southeast. The sandstone clastic components reveal multiple sources, including the magmatic arc and continental crust. Detrital zircons from six samples yield six major U–Pb age groups, including 2650–2350, 2050–1720, 1000–620, 520–380, 350–210, and 205–160 Ma. The Upper Triassic sediments contain a relatively high density of 2490, 1860, 810, 440, and 230 Ma, which are mostly consistent with the QOB, northern SCC and Jiangnan Suture Zone provenances. The majority age population of 2050–1750 Ma observed within the Xujiahe Formation, is considered to be primarily sourced from northern SCC, suggesting the uplift and erosion of the northern SCC, probably imply extreme shortening between the QOB and SCC. The Baitianba and Xintiangou formations, which contain lesser 2050–1720 Ma aged zircons, indicate a period of lacustrine expansion and tectonic quiescence after the shortening. The Middle Jurassic Shaximiao Formation, and the Upper Jurassic Suining and Penglaizhen formations, involve a major age population of 2050–1720 Ma that were sourced from northern SCC, indicate another phase of uplifting of the northern SCC related to a second stage of extreme intracontinental shortening and deformation between the SCC and the QOB. In summary, the above results indicate that, an initial phase of extensive shortening between the QOB and the SCC during the Late Triassic, was followed by a period of tectonic quiescence during the Early Jurassic, and another phase of extreme intracontinental shortening between the QOB and SCC during the Middle to Late Jurassic.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 2","pages":"531-559"},"PeriodicalIF":1.4,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143439231","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":"Reduced Granitic Rocks and Related Gold Mineralisation: Implications From Chronology, Geochemistry and Sr–Nd–Hf–O Isotopic System of Early Cretaceous Granites From the Wulong Gold Deposit, Liaodong Peninsula, NE China","authors":"Jun Liu,&nbsp;Xiao-Tong Wang,&nbsp;Jun-Cheng He,&nbsp;Tie-Gang Li","doi":"10.1002/gj.5146","DOIUrl":"https://doi.org/10.1002/gj.5146","url":null,"abstract":"<div>\u0000 \u0000 <p>The Liaodong Peninsula is the northeastern part of the North China Craton and hosts abundant Late Mesozoic granites and associated gold deposits. The Wulong deposit contains 57.5 t Au with an average grade of 7.1 g/t and is the largest gold deposit in the Liaodong Peninsula. The Wulong gold orebodies are hosted in Mesozoic biotite granites and have a close association with synchronous granite porphyry dykes. In this study, we provide a systemic geochemical and chronological study to distinguish fertile granites from barren ones from the Wulong deposit. Our study shows that the Wulong fertile granite porphyry (high Sr/Y) and Sanguliu barren granite (low Sr/Y) have zircon U–Pb ages of 132 ± 1 and 136 ± 0.4 Ma, respectively. The fertile and barren granites share similar REE patterns by characteristic of LREE enrichment and HREE depletion. They are classified as reduced ilmenite-type granitic rocks. Petrochemistry and Sr–Nd–Hf–O isotopes show that the Wulong fertile and Sanguliu barren granites were derived from intensive crustal reworking in the North China Craton. The Wulong fertile granites were derived from mixing of lithospheric mantle–derived and thickened ancient lower crust–derived magmas. The Sanguliu barren granites were derived from partial melting of the ancient lower crust with normal crustal thickness. Geochemical features of zircon and apatite indicate that the both fertile and barren granites are similar in crystallisation temperature, water content, and oxygen fugacity. Our study suggests that magma source composition is essential to gold metallogeny, and mantle-derived components are a key indicator to distinguish fertile and barren granitoids. Exploration for gold deposits related to reduced intrusions may be promising within the Liaodong Peninsula.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1601-1621"},"PeriodicalIF":1.4,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635601","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":"Sources and Enrichment Mechanisms of Li-Rich Geothermal Springs in the Mediterranean-Himalayan Belt: Modelling From Li Isotope and Hydrochemistry","authors":"Hongkai Zhu,&nbsp;Hongbing Tan,&nbsp;Peixin Cong,&nbsp;Zhiwei Shi","doi":"10.1002/gj.5134","DOIUrl":"https://doi.org/10.1002/gj.5134","url":null,"abstract":"<div>\u0000 \u0000 <p>The eastern extension of the Mediterranean-Himalayan geothermal belt contains numerous geothermal springs with anomalously high lithium (Li) content. These springs have long discharged substantial Li resources to the surface, underscoring their potential as a Li-rich geological feature of significant interest. This study utilises field investigations of typical high-temperature, Li-rich geothermal springs in this region, along with Li isotope tracing, hydrogeochemical analysis, and simulation, to elucidate the mechanisms behind the anomalous Li enrichment in these springs and to establish a model for Li enrichment in geothermal systems. Our findings reveal that high-temperature geothermal springs along the Yarlung Tsangpo Suture Zone in Tibet exhibit the highest recorded Li concentrations, generally exceeding those in other geothermal springs in the eastern extension by 1–2 orders of magnitude, with some even reaching concentrations suitable for industrial extraction. The discrepancy between the δ⁷Li values calculated for the geothermal springs and those measured, as well as the water–rock interactions simulated by PHREEQC, suggests that the Li leached solely from surrounding rocks is insufficient to account for the observed concentrations, indicating the presence of additional Li sources. In conclusion, the anomalous Li enrichment observed in these springs results from a combination of deep magmatic fluids, regionally Li-enriched rocks, and intense water–rock interactions. The upwelling of residual magmatic fluids from partial crustal melting along the Yarlung Tsangpo Suture Zone plays a major role in forming geothermal springs with unusually high Li content. In contrast, springs formed by mantle-derived magma, volcanism, or solely by water–rock interactions generally show only slight Li enrichment.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 8","pages":"2019-2032"},"PeriodicalIF":2.2,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144814622","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":"Ce-Yb Fingerprinting of Phanerozoic Volcanic Rocks and Its Applicability to Some Archean Greenstone Belt Magmas","authors":"Subarna Baidya,&nbsp;Rajagopal Anand,&nbsp;Swayoma Bose,&nbsp;Nongmaithem Lakhan Singh","doi":"10.1002/gj.5126","DOIUrl":"https://doi.org/10.1002/gj.5126","url":null,"abstract":"<div>\u0000 \u0000 <p>Rare earth element fractionation in volcanic rocks can be used to recognise both petrogenetic processes and tectonic settings. We present a simple geochemical modelling approach using Ce<span></span>Yb proxy employing the Magma Chamber Simulator tool and the binary mixing model to understand the range and the limits of variation in the enrichment of incompatible trace elements, brought about in evolved magmas by differentiation processes in known Phanerozoic tectonic settings in conjunction with the Th<span></span>Nb<span></span>Yb proxy. By extending this approach to the volcanic rocks of the Meso-Neoarchean greenstone belts it is observed that rocks, which fall beyond the limits set by binary mixing and fractional crystallisation in a bivariant trace element plot were most likely generated by the modification of the mantle source by subducting slab-derived fluids prior to the melting of the source and the diversification of the magmas into differentiated rocks. Subduction–accretion process was established at least by the Meso-Neoarchean. The greenstone belts of the Dharwar and Yilgarn cratons represent Archean analogues of oceanic crust that were predominantly emplaced in a convergent-margin tectonic setting and probably acted as suture zones that juxtaposed continental crustal masses by horizontal tectonic forces.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 2","pages":"509-530"},"PeriodicalIF":1.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438736","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":"Discovery and Significance of the Neoproterozoic Gabbro Intrusion in the Bayan Obo Group Along the Northern Margin of the North China Craton","authors":"Hao Hu,&nbsp;Yuan Li,&nbsp;Zhiguang Zhou,&nbsp;Guosheng Wang,&nbsp;Shen Gao,&nbsp;Jianfeng Chen,&nbsp;Chenfei Feng","doi":"10.1002/gj.5132","DOIUrl":"https://doi.org/10.1002/gj.5132","url":null,"abstract":"<div>\u0000 \u0000 <p>The tectonic position of the North China Craton within the Rodinia supercontinent remain unclear due to the scarcity of early Neoproterozoic magmatic rocks in the region, resulting in limited paleomagnetic data. In this study, we report the discovery of a Neoproterozoic metamorphic gabbro intrusion within the Bayan Obo Group, located in the northwestern Bayan Obo rift zone at the northern margin of the North China Craton. This finding offers crucial geological insights into addressing this key scientific question. We utilised petrography, whole-rock geochemistry, zircon U–Pb geochronology, and Sr-Nd isotopic analysis to investigate the genesis and source of the gabbroic rock and its tectonic setting. The metamorphosed gabbro has a zircon ²⁰⁶Pb/²³⁸U weighted mean age of 925.9 ± 7.2 Ma, with low SiO₂ (46.46%–48.28%), high Na₂O (2.95%–3.56%), and low K₂O (0.761%–1.41%), and has the signature of sub-alkaline tholeiitic basalt. It is enriched in large-ion lithophile elements (Rb, Ba, Th, U, K, Pb) and depleted in high-field-strength elements (Nb, Ta). The rock is also enriched in light rare earth elements, shows a negative Eu anomaly, and has a positive <i>ε</i>Nd(<i>t</i>) value (+0.1 ~ +0.8). The metamorphosed gabbro shares geochemical characteristics and Nd isotopic compositions with contemporaneous mafic intrusions, including the 945–890 Ma mafic sills in southeastern North China Craton, the ~925 Ma Dashigou mafic dike swarm in central North China Craton, the ~925 Ma gabbro in Guyang, northern North China Craton, and the 827–819 Ma gabbro in Langshan, western North China Craton. This age suggests that the gabbro may represent a response to a large-scale mafic magmatic event in central-eastern North China Craton during the early Neoproterozoic, potentially linked to the initial breakup of the Rodinia supercontinent.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 6","pages":"1409-1430"},"PeriodicalIF":1.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207002","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":"Integrated Magnetic and Electrical Geophysical Methods for Detecting Concealed Porphyry Copper Deposits in Sedimentary Basins: A Case Study From the Western Liupanshan Basin, Northwest China","authors":"Rui Tao,&nbsp;Tai Qiang,&nbsp;Tingting Gong,&nbsp;Yongliang Sun,&nbsp;Chao Mei,&nbsp;Rui Ren,&nbsp;Ye Yang","doi":"10.1002/gj.5142","DOIUrl":"https://doi.org/10.1002/gj.5142","url":null,"abstract":"<div>\u0000 \u0000 <p>Exploration for concealed porphyry copper (Cu) deposits in sedimentary basins is challenging. Integrated geophysical exploration methods, combining electrical and magnetic techniques, have proven to be highly effective in the search for concealed metal deposits. This study focuses on the Yueliangshan area within the western Liupanshan Basin, utilising high-precision (1: 10,000) ground magnetic surveys and induced polarisation sounding for Cu exploration. The goal is to interpret geophysical anomalies to delineate Cu mineralization zones, providing a reliable theoretical basis for subsequent engineering drilling. High-precision ground magnetic surveys indicate that magnetic anomalies are primarily caused by Proterozoic to Palaeozoic metamorphosed volcanic-sedimentary rock series and magmatic intrusions. These magnetic sources are distributed along a northwest-southeast regional structural uplift zone, with the upper interface buried approximately 400 m deep. The magnetic bodies trend southwest and are steeply inclined. The induced polarisation sounding results reveal that sulphide mineralized alteration zones at the margins of concealed granodiorite bodies are responsible for the high polarizability characteristics observed in exploration sections 2 and 8. Compared to geophysical parameters from ground magnetic surveys, high polarizability obtained from induced polarisation measurements are the most effective indicators for identifying porphyry bodies that have undergone mineralized alteration. It is proposed that engineering drilling at the sites of maximum anomalies caused by mineralized alteration offers a high feasibility for discovering Cu deposits. Finally, this study summarises the comprehensive exploration indicators for concealed porphyry Cu deposits in sedimentary basins and proposes a generalised exploration model.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 8","pages":"1942-1955"},"PeriodicalIF":2.2,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144814623","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":"Petrogenesis and Tectonic Setting of the Xishan Pluton in Nanling Range: Lithogeochemistry, Zircon U–Pb Chronology and Hf Isotope Evidence","authors":"Jianfeng Li,&nbsp;Wei Yang,&nbsp;Jianming Fu,&nbsp;Youyue Lu,&nbsp;Shunbo Cheng,&nbsp;Zhengwei Qin","doi":"10.1002/gj.5096","DOIUrl":"https://doi.org/10.1002/gj.5096","url":null,"abstract":"<p>In this article, a systematic LA-ICP-MS zircon U–Pb geochronology study was carried out on the Xishan pluton in Nanling Range. The results show that the formation ages of granitic porphyroclastic lava, medium-fine-grained porphyritic granite, and dacite are 154.0 ± 1.2–156.1 ± 2.0, 153.2 ± 0.9–157.3 ± 3.2, and 151.2 ± 3.1 Ma, which are determined to be the early Yanshanian. Geochemical data show that the Xishan pluton was characterised by rich silicone-alkali and poor calcium–magnesium with K₂O/Na₂O ratios of 1.65–2.22, Al₂O₃ of 1.00–1.14, and FeO*/MgO ratios of 8.33–19.0 (with an average of 12.94). The rare earth content of granites ranges from 322.92 to 441.54 ppm, which is significantly higher than the world average. The rare earth element distribution curve is right-leaning light rare earth enrichment type, with obvious negative europium anomaly, and the δEu values range from 0.06 to 0.24; These rocks are enriched in high-field-strength elements (HFSEs, e.g., Ga, Y, Nb, Zr, and Hf) and depleted elements such as Ba, Nd, Sr, P, Ti, etc, with Ga/Al ratios of 2.95 × 10⁻⁴ to 4.59 × 10⁻⁴ (with an average of 3.50 × 10⁻⁴); Zr + Nb + Ce + Y of 367.1–652.5 ppm (with an average of 441.95 ppm) and zircon saturation temperatures Tzr is 755.04°C–892.50°C (with an average of 810.04°C), similar to geochemical features of A-type granites. The Hf isotope study shows that the <i>ε</i>\u0000 _Hf(<i>t</i>) of the Xishan pluton ranges from 2.11 to −8.77, and the petrographic, geochemical and available data confirm that it originates from the mixing of crustal and mantle-derived magma, and the contribution of the latter is &lt; 10%. The hafnium II model age of the Xishan pluton is 1251–1766 Ma, which confirms that its source rocks were detached from the mantle reservoir at the time of the Middle Proterozoic. Combined with the evolutionary history of the Nanling Range area, it is assumed that the Jiangnan Orogenic Zone was partially reactivated by the continuous lateral subduction of the ancient Pacific Plate in the Late Mesozoic, which triggered partial melting of the crust to form the A₂-type granite type, which is the origin of the Xishan pluton.</p>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 3","pages":"674-699"},"PeriodicalIF":1.4,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530787","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":"Influence of Low-Grade Solid Potash Mineral Composition on Potassium Extraction and Lithium Distribution During Solution Mining in Mahai Salt Lake, Qaidam Basin","authors":"Pengyu Long,&nbsp;Xianfu Zhao,&nbsp;Yanjun Zhao,&nbsp;Ik Woo,&nbsp;Jiangmin Du,&nbsp;Zhaoxu Wang,&nbsp;Yufei Hu","doi":"10.1002/gj.5115","DOIUrl":"https://doi.org/10.1002/gj.5115","url":null,"abstract":"<div>\u0000 \u0000 <p>As high-grade potash resources become increasingly scarce and lithium is recognised as a valuable co-product, the low-grade solid potash deposits in the Mahai Salt Lake, Qaidam Basin, have become increasingly significant targets for potash resource development. However, the inefficient release of potassium from these low-grade ores constrains their economic feasibility for industrial use. This study addresses this challenge by employing x-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and observational borehole monitoring data to systematically analyse the mineralogical characteristics of these ores and their influence on potassium ion release during solid–liquid conversion. The results identify carnallite, sylvite, and polyhalite as the primary potash minerals, with a significant spatial variations across the study area that directly impact potassium ion release and migration. Sylvite and carnallite in shallow strata are more reactive with solvents, facilitating rapid potassium ion release, whereas polyhalite, hosted within the intercrystalline clastic materials of halite, demonstrates limited pore connectivity, resulting in a slower release rate. Monitoring borehole data indicate that variations in solvent injection volumes cause significant fluctuations in water levels and potassium ion concentrations, thereby affecting potash dissolution rates. As solution mining progresses, high-lithium areas gradually expand, with lithium concentrations in brine reaching up to 120.4 mg/L and generally ranging from 20 to 70 mg/L. The spatial correlation between potassium and lithium distribution suggests that lithium can be effectively recovered as a co-product. Adjustments in solvent injection rates and concentrations, based on mineral distribution and monitoring data, are essential for optimising the dissolution efficiency of both potassium and lithium during production.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 8","pages":"1812-1824"},"PeriodicalIF":2.2,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144815102","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 and Source Characteristics of Dykes Straddling the Panvel Flexure, India and Their Relationship to the Deccan-Aged Seychelles Intrusives","authors":"Raghuram,&nbsp;Raymond A. Duraiswami,&nbsp;S. V. Chinchu,&nbsp;Chandan Saha","doi":"10.1002/gj.5123","DOIUrl":"https://doi.org/10.1002/gj.5123","url":null,"abstract":"<div>\u0000 \u0000 <p>Several dykes straddle the Panvel flexure (PF) and intrude the compound pāhoehoe flows in the West Coast of India. Three geochemically distinct groups of dykes, that is, olivine normative tholeiites, quartz normative tholeiites with geochemical affinity to the Bushe, Poladpur and Ambenali formations and a nepheline normative alkali basalt are emplaced straddling the PF, striking parallel to the West Coast Fault (WCF) and the PF (NNW–SSE). The quartz normative tholeiites from the present study are restricted to the east of the PF axis and olivine normative tholeiites dominate west of the PF axis. The presence of olivine-bearing dykes west of the PF axis may represent the upper parts of a plumbing system that has tapped either a large basic magma chamber variably, that accumulated fairly large quantities of primary magma at the crust–mantle boundary or a distinct but linked magma reservoir that underwent different AFC processes to produce the olivine tholeiites straddling the flexure. Quartz tholeiite east of the PF axis represents differentiated products of these reservoirs. WCF and PF are imprints of the separation of Seychelles from India associated with the rifting subsidence of the crust and upliftment of the Western Ghats. Deccan age (69.1–73.5 Ma) dykes occurring in Praslin, Félicité and Mahé islands of Seychelles are quartz normative, olivine normative and nepheline normative, respectively, forming three distinct geochemical groups and are chemically akin to the Bushe and Khandala formations when plotted in bivariate ratio plots. Trace and REE-based models of intrusions straddling the PF and their counterparts in the Seychelles; indicate partial melting of dominantly garnet lherzolite source. Partial melting curves show olivine normative and quartz normative tholeiite dykes from Seychelles to dominantly have spinel lherzolite source with different degrees of partial melting. In contrast, the nepheline normative dyke has a spinel + garnet lherzolite source.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 6","pages":"1271-1303"},"PeriodicalIF":1.4,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206799","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}