Journal of Geochemical Exploration最新文献

{"title":"GEMAS: Boron as a geochemical proxy for weathering of European agricultural soil","authors":"Philippe Négrel ,&nbsp;Anna Ladenberger ,&nbsp;Alecos Demetriades ,&nbsp;Clemens Reimann ,&nbsp;Manfred Birke ,&nbsp;Martiya Sadeghi ,&nbsp;The GEMAS Project Team","doi":"10.1016/j.gexplo.2024.107618","DOIUrl":"10.1016/j.gexplo.2024.107618","url":null,"abstract":"<div><div>About a century ago, B was recognised as an essential element for the normal growth of plants and terrestrial organisms. Limitations for plant development have been recognised in agricultural systems, particularly in highly weathered soil. Boron is rarely analysed in whole rock or soil analysis, as it requires specific analytical techniques. It is often determined, after partial extraction (aqua regia or Ca<img>Cl), usually on a limited number of samples. Many more questions than answers exist about the environmental behaviour of B.</div><div>We present B contents in agricultural soil samples (0–10 cm) collected in 33 European countries (5.6 million km²) during the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) continental-scale project. The B content, determined by ICP-MS following hot aqua regia extraction, varies in European agricultural soil from 0.5 to 49 mg/kg (median 2.42 mg/kg, <em>n</em> = 2108), which is somewhat similar to total B estimates for the Upper Continental Crust (17–47 mg/kg). Its spatial distribution in agricultural soil shows a patchy pattern with low values in regions with granitic bedrock and high contents in soil formed over limestone and in volcanic areas.</div><div>Boron geochemical behaviour in soil is strongly dependent on other factors such as pH, CEC, presence of organic matter, clay and secondary oxides and hydroxides. Boron geochemical mapping at the continental scale in arable soil allows investigations of plant health, i.e., the beneficial and adverse effects due to the nutritional status of boron.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107618"},"PeriodicalIF":3.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace element geochemistry and zircon U-Pb geochronology of mafic sills from the Karagwe Ankolean Belt of northwestern Tanzania: Implications for petrogenesis and Ni-Cu-Co prospectivity","authors":"Gerald L. Chuwa ,&nbsp;Charles H. Kasanzu ,&nbsp;Emmanuel O. Kazimoto ,&nbsp;Francisco E. Apen","doi":"10.1016/j.gexplo.2024.107614","DOIUrl":"10.1016/j.gexplo.2024.107614","url":null,"abstract":"<div><div>In northwestern Tanzania, mafic sills intruded the Akanyaru and Kagera Supergroup rocks in the Mesoproterozoic Karagwe-Ankolean Belt (KAB). Trace element geochemistry and U<img>Pb geochronology results are reported to unravel petrogenetic and geochronological evolution of the sills in order to place constraints on Ni-Cu-Co prospectivity of the KAB. The sills are subalkaline gabbronorite and dolerite. They are relatively evolved Mg# = 43–69, with transitional metal contents lower than juvenile mafic-ultramafic rocks of the Kabanga-Musongati Alignment (KMA) intrusions. The sills can be subdivided into western and eastern swarms that display similar geochemical characteristics, including enrichment in LREE (Light Rare Earth Elements), LILE (Large Ion Lithophile Elements), Pb, Th, and U relative to HFSE (High Field Strength Elements). They are characterised by depletions of Nb-Ta-Ti in primitive mantle normalised spiderplots, enrichments in LREE and relatively flat MREE and HREE with negative Eu anomalies Eu/Eu* = 0.74–0.94 in chondrite normalised REE spiderplots. Together with elemental trace element ratios Nb/Yb, Th/Yb, Zr/Nb, Ba/Nb, and Nb-Yb-Ti index suggest derivation of the mafic sills from a sub-continental lithospheric mantle source followed by fractional crystallisation and crustal contamination.</div><div>Zircon U<img>Pb geochronology yields a concordant weighted age of 1424 ± 13 Ma for a gabbronorite in the western sills and an upper age intercept of 1411 ± 54 Ma for a dolerite in the eastern sills. The emplacement ages are similar to those of the KMA and the Lake Victoria Dolerite Dyke Swarm (LVDDS). Temporal and geochemical similarities with the KMA and LVDDS supports for emplacement of the mafic sills in an intracratonic rift setting. Although the KAB sills are relatively more geochemically evolved, they share similar evolutionary path with Ni-Cu-Co mineralised juvenile KMA intrusions, sensu stricto interaction with sulphur bearing country rocks. We suggest that trace elements geochemistry including chalcophile elemental ratios (Ni/Cr and Cu/Zn) of the sills be applied as vectors to locate prospective Ni-Cu-Co targets in the KAB.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"268 ","pages":"Article 107614"},"PeriodicalIF":3.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"REE-bearing phosphate mineral chemistry for iron sulfide‑copper‑gold exploration: A study at Jericho, NW Queensland, Australia","authors":"Travis Batch ,&nbsp;Caroline Tiddy ,&nbsp;Adrienne Brotodewo ,&nbsp;David Giles ,&nbsp;Glen Little ,&nbsp;Antonio Belperio ,&nbsp;Michael Taylor ,&nbsp;Vaclav Metelka","doi":"10.1016/j.gexplo.2024.107608","DOIUrl":"10.1016/j.gexplo.2024.107608","url":null,"abstract":"<div><div>We present mineral chemistry data from the rare-earth element (REE) bearing phosphates monazite and rhabdophane sampled from the Jericho iron sulfide‑copper‑gold (ISCG) deposit in the Cloncurry District, north-west Queensland. REE-bearing phosphates sampled from within the narrow mineralised sequence have a characteristic mineralogy and chemical signature compared to REE-bearing phosphates sampled from the unmineralised metamorphic host sequences only meters away. The mineralised samples contain the hydrated REE-bearing phosphate rhabdophane (REEPO₄ · n H₂O) which occurs as veins and ‘spongy’ textured grains in association with sulfide minerals and commonly replacing apatite. In contrast, the metamorphic host rocks contain monazite (REEPO₄) with metamorphic textures and are rarely associated with sulfide minerals. Rhabdophane and monazite have comparable ΣREE and REE profiles, however the rhabdophane grains are characterised by lower Th contents and higher Ca, S and water contents. Molar ratios of S/Th and Ca/Th, determined by electron probe microanalyser (EPMA), can be used to discriminate between REE phosphates from within the Jericho mineralisation from those not associated with mineralisation. The presence of hydrated rhabdophane also indicates the temperature of mineralisation is at or below 200–250 °C.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107608"},"PeriodicalIF":3.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of potentially toxic elements in some wild edible plants of district Doda, Jammu and Kashmir, India","authors":"Sania Hamid ,&nbsp;Devendra Kumar Pandey ,&nbsp;Deepika Singh","doi":"10.1016/j.gexplo.2024.107604","DOIUrl":"10.1016/j.gexplo.2024.107604","url":null,"abstract":"<div><div>Wild edible plants have played a crucial role since ages, in sustaining the local communities across globe, particularly during food scarcity, by supplementing the household diets. Despite their significance, the nutritional composition of wild edible plants has been inadequately researched and generally poorly understood. Moreover the studies of nutritional contents usually overlook the presence of potentially toxic elements(PTEs) which may be detrimental to the human health. This study was aimed at assessing the levels of PTEs (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sr and Zn), in selected wild edible plants traditionally consumed by rural people of District Doda. For this purpose the leaves of three wild edible plants, namely <em>Taraxacum officinale, Urtica dioica</em> and <em>Phytolacca acinosa</em> were collected, air-dried and processed into powder. The plant samples were analyzed using Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The findings of this study exhibited that PTEs were detectable in all the three tested wild edible plants. The levels of PTEs (mg/1000gdw) were found to be Cu (18.1 to 36.1), Fe (646.6 to 1457.8), Mn (80.4 to 207.6), Se (0.1 to 0.3) and Zn (58.2 to 86.8), PTEs Al, As, Ba, Cd, Co, Cr, Hg, Ni, Pb, and Sr were also detectable in all the three analyzed plant samples. The Al content was found to be highest among these PTEs (427.7 to 1224.4 mg/ 1000 g dw) which can pose health risks.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107604"},"PeriodicalIF":3.4,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution, enrichment characteristics and prospecting potential of lithium in Uzbekistan: Insights from 1:1 million geochemical mapping","authors":"Jifei Cao ,&nbsp;Wenyuan Li ,&nbsp;Maksud Isokov ,&nbsp;Jakhongir Movlanov ,&nbsp;Miraziz Mirkhamdamov ,&nbsp;Zhongping Ma ,&nbsp;Kai Weng ,&nbsp;Kai Cao ,&nbsp;Guanglu Meng","doi":"10.1016/j.gexplo.2024.107606","DOIUrl":"10.1016/j.gexplo.2024.107606","url":null,"abstract":"<div><div>With the world economy gradually shifting to alow‑carbon and greener model in recent years, there is a growing need for developing key metals like lithium in economic development. Economic growth has sped up the country's shift to a green economy along with Uzbekistan's reform and opening up, and the country's developing major mineral resources, such as lithium, have garnered a lot of attention. Owing to lithium resource protential of Uzbekistan is unclear, it is important to examine the possibility of lithium mineralization. The distribution and enrichment characteristics of lithium in the Uzbeksitan Tianshan are studied in this paper, based on geochemical mapping data at a 1:1000000 scale. It's concluded that stream sediments from the Tianshan region of Uzbekistan have higher concentration of lithium than the continental crust, and the South Tianshan has the highest lithium content. Lithium mineralization has been found in the lithium-geochemical anomaly areas in the eastern part of Uzbekistan South Tianshan through field investigation. Spodumene pegmatite, the first instance of pegmatitic type lithium mineralization in this region and even in the Tianshan orogenic belt of Central Asia. In conjunction with the geological background analysis, the metallogenic potential of lithium was assessed, resulting in the identification of four regions with lithium geochemical anomaly, and these sites will serve as target areas for Li deposits prospecting work in the future. This work has significant implications for the advancement of our understanding of the metallogenic theory of pegmatite-type Li deposits, as well as practical guiding significance for lithium ore prospecting in the Tianshan orogenic belt of Central Asia.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"268 ","pages":"Article 107606"},"PeriodicalIF":3.4,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Apatite-rich zones in the Uppermost Upper Zone, Northern Limb, Bushveld Complex: Possible non-conventional source of REE and TiO2” [J. Geochem. Explor. (2024) [107498] [263C]]","authors":"Hakundwi Mandende ,&nbsp;Themba Mothupi","doi":"10.1016/j.gexplo.2024.107589","DOIUrl":"10.1016/j.gexplo.2024.107589","url":null,"abstract":"","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107589"},"PeriodicalIF":3.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid origins and ages of Au mineralization of the Hosen 8-2 vein, Hishikari deposit, Kagoshima, Japan","authors":"Jonathan Macuroy ,&nbsp;Ryohei Takahashi ,&nbsp;Akira Hara ,&nbsp;Yoshinori Okaue ,&nbsp;Akira Imai ,&nbsp;Pearlyn Manalo ,&nbsp;Hinako Sato ,&nbsp;Andrea Agangi","doi":"10.1016/j.gexplo.2024.107602","DOIUrl":"10.1016/j.gexplo.2024.107602","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The oxygen and hydrogen isotope ratios of ore-forming fluids and formation ages were determined using quartz, adularia, and clay minerals in the Hosen 8-2 vein at −5 ML of the Hishikari deposit. Electrum, the dominant ore mineral, is found exclusively in the early band composed of microcrystalline quartz, granular adularia, and smectite. A relatively low Au-grade zone with Au grades below 100 ppm is identified in the southwestern part of the vein, while a ∼25-meter-wide bonanza zone with Au grades up to 10,800 ppm was identified in the central part. The northeastern part of the vein is referred to as the high Au-grade zone, with Au grades between 100 and 1000 ppm.&lt;/div&gt;&lt;div&gt;The calculated fluid δ&lt;sup&gt;18&lt;/sup&gt;O values of the bonanza and high Au-grade zones calculated from quartz in the Hosen 8-2 vein are heterogenous (−6.3 to −0.8 ‰, and −6.8 to −2.9 ‰, respectively). This wide variation indicates the association of the mineralized zones with the boiling zone of upwelling deep fluids and the subsequent mixing with shallow meteoric water, which can be a useful vector of highly mineralized zones in the Hishikari deposit. Conversely, the low Au-grade zone is characterized by lower and more homogenous calculated fluid δ&lt;sup&gt;18&lt;/sup&gt;O values (−5.2 to −4.0 ‰) that are closer to the isotopic composition of meteoric water.&lt;/div&gt;&lt;div&gt;The fluids that precipitated electrum and clay minerals have high δ&lt;sup&gt;18&lt;/sup&gt;O values (+3.0 to +7.6 ‰) and low δD values (−132 to −100 ‰), which can be caused by the interaction between deeply circulating meteoric water and the sedimentary rocks of the Shimanto Supergroup at temperatures about 200–350 °C. It is also possible that δD values below −100 ‰ reflect contributions from waters released from Fe-poor hydrous sheet silicates in the host rocks.&lt;/div&gt;&lt;div&gt;The δ&lt;sup&gt;18&lt;/sup&gt;O values of fluids calculated from adularia that formed after the early clay band range from −2.9 to +1.2 ‰. The progressive decrease of the fluid δ&lt;sup&gt;18&lt;/sup&gt;O values across the paragenetic sequence can be attributed to the influx of &lt;sup&gt;18&lt;/sup&gt;O-depleted meteoric waters that mixed with Au-bearing &lt;sup&gt;18&lt;/sup&gt;O-enriched deep fluids.&lt;/div&gt;&lt;div&gt;The calculated fluid δD values of mixed smectite, illite, and interstratified chlorite-smectite from the altered host rock are much higher (−87 to −57 ‰) than those of the clays from the vein, although their fluid δ&lt;sup&gt;18&lt;/sup&gt;O values are relatively similar (−0.3 to +10.2 ‰). These values indicate that the clays from the altered host rock may have originated from the water-rock interaction between shallow fluids and the volcanic rocks of the Hishikari Lower Andesites.&lt;/div&gt;&lt;div&gt;&lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar dating of four adularia separates from the Hosen 8-2 vein yielded plateau ages from 0.930 ± 0.002 to 0.945 ± 0.001 Ma. The crystallization age of the low Au-grade zone (0.930 ± 0.002 Ma) overlaps within error with that of the bonanza zone (0.932 ± 0.002 Ma), suggesting roughly similar ages ","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"268 ","pages":"Article 107602"},"PeriodicalIF":3.4,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of pegmatites in the La Motte Batholith area, Preissac-La Corne Plutonic Suite, Abitibi Subprovince and its implications for exploration","authors":"Sabrine Rajhi ,&nbsp;Marc Legault ,&nbsp;Hubert Mvondo ,&nbsp;Robin Potvin","doi":"10.1016/j.gexplo.2024.107601","DOIUrl":"10.1016/j.gexplo.2024.107601","url":null,"abstract":"<div><div>This project focuses on the study of pegmatite characteristics in the La Motte Batholith (LMB) sector in the Abitibi Subprovince, located between the cities of Rouyn-Noranda and Val d'Or, and approximately 30 km west of the North American Lithium mine (101.9 Mt @ 1.06 % Li₂O; Sayona Québec). The study area hosts mineralizations in critical and strategic minerals, most notably the Authier deposit, which are exclusively associated with Li-Cs-Ta pegmatites. The aim of the study is to characterize the mineralogical and geochemical properties of the pegmatites in the sector to better target lithium exploration. This characterization enables the subdivision of various families of pegmatites in the LMB sector, ranging from barren pods to spodumene-rich dykes. Within the LMB, the pegmatitic facies exhibit chemical characteristics similar to those of intersecting pegmatite dykes, suggesting a genetic link between the La Motte Batholith monzogranite and the different pegmatite families despite a possible age difference of several million years. The results also confirm that elemental ratios from whole-rock analyses (K/Rb, K/Cs, Nb/Ta, Mg/Li, and Zr/Hf) within lithium-bearing dykes show the lowest values compared to other dykes, regardless of the sampling location within the same dyke. Potassium feldspar and muscovite microprobe analyses from different pegmatites also reveal K/Rb and K/Cs ratios similar to whole-rock analyses, thereby strengthening the assessment of the fractionation degree of the LMB pegmatites. These ratios thus allow for targeting sectors hosting highly fractionated dykes even where spodumene has not yet been identified.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107601"},"PeriodicalIF":3.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced exploration of rare metal mineralization through integrated remote sensing and geophysical analysis of structurally-controlled hydrothermal alterations","authors":"Mohamed A. Abdelkader ,&nbsp;Yasushi Watanabe ,&nbsp;Ali Shebl ,&nbsp;Mohamed Badawi ,&nbsp;Maher Dawoud ,&nbsp;Hanaa A. El-Dokouny ,&nbsp;Árpád Csámer ,&nbsp;Mahmoud Abdellatif","doi":"10.1016/j.gexplo.2024.107598","DOIUrl":"10.1016/j.gexplo.2024.107598","url":null,"abstract":"<div><div>Fusing multi-source (remote sensing and geophysical) data and diverse approaches validation in targeting hydrothermal alteration and structural anomalies enhances the potential for accurately detecting and characterizing mineralization zones. Sentinel 2 data and ASTER were processed for lithological and hydrothermal alteration mapping in the rare metal-rich Umm Naggat area (Egypt). Different image processing techniques were implemented, including false color composites, minimum noise fraction, band rationing, band math, mineral indices, relative absorption band depth, and constrained energy minimization. The rare metal-bearing Umm Naggat younger granite (NYG) pluton was lithologically discriminated and intra-differentiated to mafic-rich biotite granites, mafic-poor alkali feldspar granites, and albitized granites. Extensive hydrothermal alterations, such as albitization, ferrugination, propylitization, argillization, and phyllitization, overprint the NYG pluton. Normalized standard deviation, automatic lineament extractions, and trend analysis highlighted the key structural directions (NW, NNW, NNE, and NE) and distinguished the NYG pluton as a moderate to high structural density zone. The high structural density and intensive alteration zones are spatially associated and more localized within the NYG pluton than the surrounding rocks. Spatial overlay analysis confirmed that the hydrothermal alterations and fluid circulation systems are structurally-controlled. Furthermore, the hydrothermal alteration mapping and structural analysis outcomes were verified by combining fieldwork, slab polishing, petrographic investigations, and mineral chemistry through semi-quantitative scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and quantitative electron probe microanalysis (EPMA) analysis. As a result, the hydrothermal genesis of rare metal-bearing minerals (Nb-rutile, Nb-ilmenite, and columbite) close to or incorporated within alteration minerals (chlorite, muscovite, and hematite) is confirmed from the alteration zones (propylitic, phyllic, and ferruginated). In addition, biotite muscovitization and chloritization significantly contribute to the secondary rare metal enrichment. The current study emphasizes the extensive distribution of secondary rare metal-bearing minerals within the entire NYG pluton (not only limited to the northern albitized granite as depicted by previous studies), which might shed light on these hydrothermally-altered younger granites as a new potential source for Nb and Ta in Egypt.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107598"},"PeriodicalIF":3.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical and isotopic characterization of the shallow aquifers from the Mugello Basin (Tuscany, central Italy): Implications for assessing a monitoring network in a seismically active area","authors":"Lorenzo Chemeri ,&nbsp;Jacopo Cabassi ,&nbsp;Franco Tassi ,&nbsp;Francesco Capecchiacci ,&nbsp;Andrea L. Rizzo ,&nbsp;Stefano Caliro ,&nbsp;Orlando Vaselli","doi":"10.1016/j.gexplo.2024.107600","DOIUrl":"10.1016/j.gexplo.2024.107600","url":null,"abstract":"<div><div>The Mugello Intermontane Basin (MIB) is located 30 km north of Florence (Tuscany, central Italy) and shows high seismicity with historical events characterized by M_w ≥ 6, e.g., on June 13, 1542 (M_w = 6.0) and June 29, 1919 (M_w = 6.4). Progresses in the identification of seismic tracers in geofluids has been made in the last decades, although reference values for a given area are necessary to assess hydrogeochemical anomalies prior to earthquakes. In this study, a detailed characterization of the chemical and isotopic composition of the natural waters discharging from MIB was performed. The aims were to (i) constrain the geochemical processes controlling the chemistry of waters and dissolved gases, (ii) assess the influence of deep-seated fluids in the shallow environment, and (iii) evaluate the suitability of geochemical parameters as reliable tracers for seismic activity. Two different types of waters were recognized, being characterized by: (A) calcium-bicarbonate (Ca-HCO₃) composition, positive Eh values (150–200 mV), slightly alkaline pH (&lt;8.3), and an N₂-dominated dissolved gas phase; (B) sodium-bicarbonate waters (Na-HCO₃,) composition, negative Eh (&lt; −180 mV), pH &gt; 8.5, high contents in F, B and Li, and enrichments in dissolved CO₂ and CH₄. The chemistry of waters of group (A) is controlled by dissolution processes involving carbonate rocks, while the Na-HCO₃ waters likely result by prolonged water-silicate rock interactions and probably associated with longer circulation pathways. Argon (⁴⁰Ar/³⁶Ar) and carbon (δ¹³C in CO₂ and CH₄) isotopes indicate a predominant circulation within local aquifers by shallow fluids. Instead, helium (³He/⁴He) isotopes in dissolved gases highlighted a contribution up to 6 % by mantle/magmatic fluids probably rising through deep faults. The results obtained suggest that trace elements and the isotopic signatures of dissolved CO₂, CH₄, and He may represent reliable seismic tracers for the MIB on the basis of which a monitoring network could be deployed.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"267 ","pages":"Article 107600"},"PeriodicalIF":3.4,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}