Chemie Der Erde-Geochemistry最新文献

{"title":"Capability assessment of Sentinel-2 imagery for graphite deposits exploration","authors":"Muhittin Karaman","doi":"10.1016/j.chemer.2024.126117","DOIUrl":"10.1016/j.chemer.2024.126117","url":null,"abstract":"<div><div><span><span>Graphite, a critical raw material for high-technology industries, is used as an anode in lithium-ion batteries due to its high thermal and electrical conductivity and high-temperature resistance. The study evaluates the use of Sentinel-2 satellite images in exploring new graphite deposits, demonstrating the effectiveness of remote sensing methods<span> and comparing different classification methods. It also introduces new graphite indices, the Normalized Difference Graphite Index (NDGI) and the Graphite Band Math Index (GBMI), which differentiate the spectral signatures<span> of graphite mineralization from other land cover spectral signatures. The study focuses on creating a reference graphite mineralization spectral library, developing an image-based optimum graphite spectral library from Sentinel-2 satellite images, evaluating the performance of Spectral Angle Mapper (SAM), Spectral Information Divergence (SID), and Constrained Energy Minimization (CEM) classification methods, and selecting suitable threshold values for classification. The Kütahya-Oysu Graphite Mine in Turkey was chosen as the training area, while other test sites include Xinghe-Huangtuyao Graphite Mine (Inner Mongolia, China), the Pingdu Graphite Deposit (Shandong, China), the Jixi-Liumao Graphite Deposit (Heilongjiang, China), the Luobei-Yunshan Graphite Deposit (Heilongjiang, China), the Balama Graphite Project (Mozambique), and the Molo Graphite Project (Madagascar). In Oysu, a significant graphite deposit in Turkey, graphite ore is formed in metamorphic graphite schist and graphite-bearing muscovite schist. The Oysu's graphite ore is microcrystalline and macrocrystalline type of graphite and displays unique absorption at 704 and 2225 nm of full-spectrum wavelengths, as well as at 740 or 783 nm of the spectral detection range of Sentinel-2. The Sentinel-2 sensor, which has been widely used in geological applications, produces useful data for graphite exploration on a large scale. Sentinel-2's high </span></span></span>spectral resolution in the VNIR region makes it useful for exploring graphite deposits. Data-driven approaches like NDGI and GBMIs indices reveal graphite-related mineralization areas, while </span>supervised classification methods map graphite ratios using reference end-member spectral. A knowledge-based probabilistic algorithm, SID, measures spectral discrepancy probability, resulting in more successful graphite mineralization mapping. Lower threshold values (0.050–0.060) increase the probability of pure graphite areas.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 4","pages":"Article 126117"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140779921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating late Mesoarchean crustal dynamics in the North China Craton through 2.84 Ga TTG gneisses of the Xiong'ershan area","authors":"Heng Liu ,&nbsp;Lei Liu ,&nbsp;M. Santosh ,&nbsp;Tianyang Hu ,&nbsp;Inkyeong Moon","doi":"10.1016/j.chemer.2024.126195","DOIUrl":"10.1016/j.chemer.2024.126195","url":null,"abstract":"<div><div>The late Mesoarchean era was a critical period for the Earth's geodynamic regime. However, it remains unclear which geodynamic regime dominated this stage and how different geodynamic regimes transitioned or interacted with each other. From the perspective of crust-mantle interactions, effectively identifying different geodynamic regimes and establishing corresponding geochemical indicators are key to addressing these scientific questions. The Mesoarchean era is highlighted as a key phase in the initial formation of Earth's crust. This research delves into the late Mesoarchean TTG rock suite located in the Xiong'ershan region to shed light on the crustal dynamics of the Mesoarchean era within the North China Craton (NCC). These rocks exhibit zircon U-Pb ages of 2836 ± 26 Ma and display characteristics such as Mg^# (48–66), negative Eu anomalies (0.68–0.83), and relatively low Sr/Y (23.01–47.26) and (La/Yb)_N (5.24–39.85) ratios. Zircon grains from these rocks reveal ε_Hf(t) values spanning 0.3 to 3.6, reflecting Hf model ages between 2963 and 3087 Ma. ε_Nd(t) values of 3.23 with Nd model ages for the whole rock mass peak at 2872 Ma, indicating the formation of juvenile crust during this era. Zircon δ¹⁸O isotopic values (4.73–6.29 ‰, with an average of 5.32 ‰) suggest a mantle-derived origin for the magma. Magma crystallization temperatures, estimated using zircon Ti-thermometry, were between 607 and 725 °C. The TTG gneisses show moderate Ce/Sr ratios (0.06–0.26) and Y content (7.1–23.8 ppm), consistent with medium-pressure formation conditions. The observed depletion in HFSE (e.g. Nb, Ta, Zr, Hf, average value is 149.6) and HREE (6.22–14.99) alongside enrichment in LILE (e.g. Rb, Sr, Ba, average value is 993.9) and LREE (53–156) in these late Mesoarchean TTG rocks from the Taihua complex suggest that they formed in an arc magmatism setting related to subduction. These findings are critical for understanding the early growth and development of the NCC's crust and affirm the theory that global subduction tectonics began around 2.8 Ga.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 4","pages":"Article 126195"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alunite and kaolinite as geochemical markers in active acid sulfate alterations of southern Italy (Panarea, La Solfatara and Ischia)","authors":"Théo Bouvart ,&nbsp;Julien Poot ,&nbsp;Augustin Dekoninck ,&nbsp;Flore Schmit ,&nbsp;Maxime Keutgen De Greef ,&nbsp;Jacqueline Vander Auwera ,&nbsp;Alain Bernard ,&nbsp;Johan Yans","doi":"10.1016/j.chemer.2024.126204","DOIUrl":"10.1016/j.chemer.2024.126204","url":null,"abstract":"<div><div>Hydrothermal alteration is a common process in volcanic and geothermally active areas. Interactions between host rock and hot, often acidic, fluids induce significant changes in texture, mineralogy, and geochemistry of the protolith, potentially impacting volcanoes stability. Southern Italy's volcanic regions are geothermally active, exhibiting conspicuous hydrothermal activity. Here, we focus on active hydrothermal acid-sulfate alteration in calc-alkaline (Panarea) and alkaline (Ischia - Solfatara) volcanic products in order to (1) spatially identify alteration assemblages using XRD, (2) determine the mobility of major and trace elements during hydrothermal alteration processes using FUS and ICP-MS, (3) estimate and compare the degree of alteration using alteration indices and elemental ratios. Our data reveal sulfur and sulfates sublimate next to the fumarole fields. Nearby fumaroles, alunite and kaolinite are the most abundant mineral phases in the alteration assemblages, often associated with amorphous silica, iron(hydr)oxides, smectites and gypsum. Kaolinite is rarely observed in La Solfatara assemblage. Comparison between the protolith and the alteration products geochemistry indicates that alteration retains the calco-alkaline or alkaline heritage, which confirms the usefulness of some chemical indices (PIA vs AI; (La + Ce)/Y vs (Zr + Hf)/(Ta + Nb) for alteration products. Despite comparable mineralogies, various degrees of alteration are observed in La Solfatara, Panarea and Ischia, constraining the alunite or kaolinite formation and highlighting local vs. global geochemical behaviors. We conclude that the (im)mobility of chemicals elements within the hydrothermal alteration - such as HFSE, REE or alkali - is mainly controlled by the protolith composition, the alteration intensity and mineralogy, pH, ionic strength and possibly crystallinity of alteration minerals.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 4","pages":"Article 126204"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Physicochemical conditions of the evolution of the volcanic-hosted Zn-Pb ± Cu epi-mesothermal vein-type deposit and its contribution to the understanding of western Anatolian metallogeny, NW Turkey","authors":"Farhad Javid ,&nbsp;Emin Çiftçi ,&nbsp;Amr Abdelnasser","doi":"10.1016/j.chemer.2023.126051","DOIUrl":"10.1016/j.chemer.2023.126051","url":null,"abstract":"&lt;div&gt;&lt;div&gt;&lt;span&gt;This study focuses on the evolution of the Kirazlıyayla volcanic-hosted Zn-Pb ± Cu epi-mesothermal vein-type deposit and its relationship to volcanism&lt;span&gt;&lt;span&gt;&lt;span&gt;&lt;span&gt; in NW Turkey. The Kirazlıyayla area has an extensive variety of geological formations, including the Karakaya, Yenipazar, Fındıcak, Sarısu Volcanics, and Mesudiye. The mineralization that formed within the Sarısu Volcanics at Kirazlıyayla mine area exhibits distinctive features, including the occurrence of crosscutting quartz and sulfide veins and veinlets, forming a network of sulfide-bearing stockworks with locally banded/bedded massive sulfide. Three mineralization phases occur across the alterations. Pyrite crystallization and &lt;/span&gt;silicification&lt;span&gt;&lt;span&gt;&lt;span&gt; alteration occurred during the first phase. In the next phase, sphalerite develops with the deposition of the first generation of galena and &lt;/span&gt;chalcopyrite occurs along with sericite, &lt;/span&gt;kaolinite, and quartz in the phyllic alterations. Dolomite and &lt;/span&gt;&lt;/span&gt;calcite minerals dominate carbonatization in the third phase, with the second generation of galena and chalcopyrite with &lt;/span&gt;tennantite. The δ&lt;/span&gt;&lt;/span&gt;&lt;sup&gt;34&lt;/sup&gt;S of the sulfides exhibited a range of values from 0.7 to 6.8 ‰&lt;sub&gt;VCDT&lt;/sub&gt;, with an average value of 2.13 ‰&lt;sub&gt;VCDT&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&lt;span&gt;&lt;span&gt;. The presence of igneous rocks in the study area provides evidence for a uniform sulfur source having magmatic signature. The variability in sulfur isotope composition can be observed in intermediate and high-sulfidation &lt;/span&gt;ore minerals&lt;span&gt;. The use of oxygen isotope&lt;span&gt; analysis has the potential to facilitate the identification of hydrothermal fluids involved in the formation of &lt;/span&gt;&lt;/span&gt;&lt;/span&gt;ore deposits&lt;span&gt;, which often exhibit a combination of magmatic and metamorphic fluids. The fluid inclusion investigations have shown two-phase liquid-vapor inclusions in both the sphalerite and quartz minerals, which could be categorized as both primary and secondary varieties. The indication of these fluid inclusions inside sphalerite and quartz implies a potential meteoric source and may be attributed to the gradual mixing of fluids responsible for ore formation, which is facilitated by the influx of &lt;/span&gt;&lt;/span&gt;meteoric water along the pathway of fluid flow. Therefore, these fluid inclusions show magmatic-meteoric mixing, resulting in the creation of low-salinity ore-forming fluids due to the interaction between magmatic fluid and diluted meteoric water, resulting in further mineralization at the late stage of mineralization. Zinc, lead, and copper in hydrothermal fluids may supersaturate under fluid mixing conditions, producing Zn-tennantite and second-generation galena minerals.&lt;/span&gt;&lt;/div&gt;&lt;div&gt;&lt;span&gt;In conclusion, the Kirazlıyayla deposit is influenced by a variety of physicochemical conditions associated with volcanism and the transportation of hydrothermal fluids. These fluids penetrate the","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 4","pages":"Article 126051"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138520617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"U–Pb zircon dating, Sr-Nd whole-rock and Lu-Hf zircon isotope analyses of the Eocene Arslandede pluton, Eastern Pontides, NE Turkey: Implications for mantle source and magma evolution","authors":"Abdullah Kaygusuz ,&nbsp;Zikrullah Samet Güloğlu ,&nbsp;Emre Aydınçakır ,&nbsp;Cem Yücel ,&nbsp;Alaaddin Vural ,&nbsp;Wolfgang Siebel ,&nbsp;Youn-Joong Jeong","doi":"10.1016/j.chemer.2024.126080","DOIUrl":"10.1016/j.chemer.2024.126080","url":null,"abstract":"<div><div><span><span>The Eastern Pontide Orogenic Belt<span> (EPOB) hosts numerous plutonic bodies with different dimensions, compositions and ages ranging from Paleozoic to Late Eocene in NE Turkey. U-Pb zircon dating suggests that the Arslandede pluton crystallized at 44.50 ± 0.29 Ma, corresponding to the </span></span>Lutetian (Middle Eocene) period. Rocks of this pluton have monzonitic character, with compositions ranging from monzodiorite to granite (SiO</span>₂<span> = 49˗71 wt%). The studied monzonitic rocks have I-type, metaluminous and shoshonitic character and are enriched in large-ion lithophile elements<span> (LILEs). The rare earth elements (REEs) have concave up shape (La</span></span>_N/Yb_N = 6.64–11.57) and show negative to slightly positive Eu anomalies (Eu_N/Eu* = 0.37–1.24). ⁸⁷Sr/⁸⁶Sr_(i) values of 0.704801–0.705102 and εNd_(i)<span> values of 1.01–1.34 correspond to the mantle series on isotope ratio diagrams. Positive εHf</span>_(i)<span> values (5.01–14.91) plot between the depleted mantle and the chondritic evolution lines. The petrological features of the rocks from the Arslandede pluton show that fractional crystallization<span> with low rates of assimilation and/or magma<span> mixing were effective during crystallization. All data show that the magma source of the pluton derived from an enriched lithospheric mantle and emplaced into the crust after differentiation in a deep seated magma chamber contaminated by relatively small proportions of crustal rocks.</span></span></span></div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 4","pages":"Article 126080"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139469454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable isotope geochemistry evidences from fossil carbonate and sulfur minerals on the origin of geothermal water, Kızıldere Geothermal Field, Western Turkey","authors":"Gülcan Bozkaya,&nbsp;Ömer Bozkaya,&nbsp;Taylan Akın","doi":"10.1016/j.chemer.2024.126089","DOIUrl":"10.1016/j.chemer.2024.126089","url":null,"abstract":"<div><div><span><span><span>The Kızıldere geothermal field, located at the eastern part of the Büyük Menderes graben in Western Turkey, is the most important geothermal reservoir suitable for electricity generation. Current and fossil </span>fumaroles<span> and alteration zones are directly related to the tectonic zones influenced by N-S directional extension since Miocene period. Associated to fossil geothermal activities carbonate (calcite, dolomite) and sulfate (gypsum, anhydrite) minerals were occurred in the form of void/crack fill and bands/lenses parallel to bedding of Neogene clastic and </span></span>carbonate rocks. The carbon (δ</span>¹³C_PDB ‰) and oxygen (δ¹⁸O_PDB ‰) isotope compositions of hydrothermal calcites and dolomites and sulfur (δ³⁴S_CDT) and oxygen (δ¹⁸O_SMOW<span><span>) isotope compositions of gypsum and anhydrites are analyzed first time and correlated current geothermal water composition. The carbon and oxygen isotope data of calcites and dolomites have similar carbon but different oxygen isotope composition which increases in the direction of surface </span>calcite<span> – drill cuttings calcite – drill cuttings dolomite – surface dolomite. The isotope compositions of calcite and dolomite minerals range between limestone and marble host rock compositions and indicate the carbonate mineral-forming fluids originated from dissolution of carbonate rocks during the circulation of hot geothermal waters. According to the calcite-CO</span></span>₂ and dolomite-CO₂<span> isotopic fractionation data for the 0–300 °C temperature range, the fossil isotope composition is higher than the composition of current CO</span>₂<span><span> and reflects relatively lower temperature conditions. The isotope compositions of gypsum and anhydrite minerals indicate that hot thermal waters dissolved terrestrial </span>evaporites and formed a sulfur-rich geothermal solution, and hydrothermal gypsum and anhydrite precipitated from this solution. The δ</span>³⁴S_CDT<span> compositions of hydrothermal gypsum and anhydrites are similar to the current geothermal water compositions. Stable isotope geochemistry data of hydrothermal carbonate and sulfate minerals in the Kızıldere geothermal field have shown that the fluids forming these minerals were originated from host rocks instead of magmatic volatiles.</span></div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 4","pages":"Article 126089"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139755129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogical and leaching characteristics of sulfur concentrate and hot filter residue from zinc–oxygen-pressure leaching","authors":"Pu Sun ,&nbsp;Guomu Chen ,&nbsp;Dongfeng Zhou ,&nbsp;Chang Wei ,&nbsp;Xingbin Li ,&nbsp;Zhigan Deng ,&nbsp;Minting Li","doi":"10.1016/j.chemer.2024.126198","DOIUrl":"10.1016/j.chemer.2024.126198","url":null,"abstract":"<div><div>The mineralogical properties and environmental impact of sulfur concentrate and hot filter residue produced from the zinc–oxygen-pressure leaching were studied through a series of characterization, including X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP–OES), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM–EDS), particle size distribution (PSD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermogravimetry and differential thermal analysis (TG–DTA). Furthermore, short-term environmental activity was assessed using the toxic leaching procedure (TCLP). The results indicated that the sulfur concentrate exhibited a coarser particle size compared with the hot filter residue, primarily appearing as spindle-shaped element sulfur (S⁰). The hot filter residue contained spindle-shaped S⁰ and rod gypsum, alongside phases of sphalerite, pyrite, and copper–silver-containing phases encapsulated by S⁰, recovering valuable metals first requires the removal of S⁰. The surfaces of both sulfur concentrate and hot filter residue were composed of S, ZnS, Al-O, PbSO₄, and SiO₂. They exhibited thermal instability and some degree of water absorption, with vigorous burning observed at temperatures ranging from 200 °C to 380 °C. The leachates from these materials exhibited increased concentrations of elements such as zinc, lead, and cadmium surpassing permissible limits, highlighting the importance of their safe disposal for the stable production of zinc–oxygen-pressure systems.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126198"},"PeriodicalIF":2.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Critical analysis between the Ossa-Morena Zone and the Galicia-Trás-os-Montes Zone, Iberian Massif: Geochemical and geochronological comparison and geodynamic implications","authors":"P. Cachapuz ,&nbsp;M. Chichorro ,&nbsp;T. Bento dos Santos","doi":"10.1016/j.chemer.2024.126168","DOIUrl":"10.1016/j.chemer.2024.126168","url":null,"abstract":"<div><p>Recent studies have suggested the existence of a correlation between the allochthonous units of NW Iberia (Galicia-Trás-os-Montes Zone - GTMZ) with SW Iberia (Ossa-Morena Zone – OMZ) in the European Variscan Belt. Such proposed equivalence is based on lithostratigraphic, tectono-metamorphic, geochronological, and geochemical affinities between these two domains, and implies that both zones had the same Neoproterozoic and early Palaeozoic basins, recording the same magmatic episodes and enduring the same tectono-metamorphic processes related to the Variscan Orogeny. As so, in order to better understand the evolution of these domains during the Ediacaran-Cambrian period, a comprehensive geochemical, isotopic and geochronological analysis of the metasediments that make up the OMZ and the allochthonous units of the GTMZ was carried out. The results show that the metasediments of OMZ and the Lower Allochthonous units of GTMZ present similar geochemical and geochronological features, having been likely deposited near each other, although small, but specific differences between both domains suggest that they do not correspond to the same depocentre. However, no geochemical, isotopic or geochronological correlation can be established with any of these domains and the Upper Allochthonous units of GTMZ. These metasediments display quite exotic features and, as such, were likely deposited in a different narrower basin, located to the W of the basins where OMZ and Lower Allochthonous units of GTMZ were deposited, thus providing precise constraints on the paleogeographic reconstruction of these domains during the Neoproterozoic to Early Ordovician dismembering of Gondwana.</p></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 3","pages":"Article 126168"},"PeriodicalIF":2.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S000928192400093X/pdfft?md5=3776dc95daaec9fc9bcf16bfecb3ff10&pid=1-s2.0-S000928192400093X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Geochronology and petrogenesis of multiple magmatic events in the Tianbaoshan orefield, NE China: Implications for tectonic evolution","authors":"","doi":"10.1016/j.chemer.2024.126141","DOIUrl":"10.1016/j.chemer.2024.126141","url":null,"abstract":"<div><p><span><span><span>Recent studies have shown that multistage magmatic and metallogenic events in NE China were dominated by the Paleo-Asian Ocean tectonic regime and the Paleo-Pacific Ocean tectonic regime. However, outstanding questions remain on the petrogenesis<span> and fertility of ore-causative magma in each metallogenic event. In this study, we report new geochronologic and geochemical data on ore-causative intrusions from the Tianbaoshan orefield in the east Jilin-Heilongjiang belt (EJHB), aiming to identify their petrogenesis, magma fertility, and their implications for the </span></span>geodynamic evolution of the EJHB. Middle </span>Permian Lishan ore-causative quartz monzodiorites with abundant mafic microgranular enclaves (MMEs) were emplaced at ca. 264.9 ± 2.6 Ma. Petrographic and geochemical characteristics (</span>⁸⁷Sr/⁸⁶Sr_(i) = 0.7049–0.7053, ε_Nd(t) = 2.9–3.7, and ε_Hf<span><span>(t) = 4.7–11.7) indicate a juvenile crust source injected by a slab-metasomatized mantle component. The Early Jurassic<span> Beishan monzogranites (ca. 192.5 ± 1.8 Ma) were generated by the partial melting of the juvenile underplating basaltic lower crust with subsequent </span></span>fractional crystallization in response to their highly evolved geochemical features, combined with their depleted Sr-Nd-Hf isotopic signature (I</span>_Sr = 0.7032–0.7037, ε_Nd(t) = 2.8–3.3, and ε_Hf<span><span>(t) = 7.2–12.2). Based on the zircon </span>trace element geochemistry, we infer that the Middle Permian quartz monzodiorites had a high oxygen fugacity (Ce</span>⁴⁺/Ce³⁺ = 40–216), potentially generating the Pb-Zn-Cu mineralization. Early Jurassic Beishan monzogranites had a lower magmatic oxygen fugacity (Ce⁴⁺/Ce³⁺<span> = 14–106), which may account for the Mo-dominated mineralization. A combination of this study and previous results corroborates that the Tianbaoshan orefield records the superposition of different tectonic regimes during metallogenesis.</span></p></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 3","pages":"Article 126141"},"PeriodicalIF":2.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141394339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Albitization related U and Th mobilization under reducing conditions","authors":"","doi":"10.1016/j.chemer.2024.126160","DOIUrl":"10.1016/j.chemer.2024.126160","url":null,"abstract":"<div><p><span><span>Hydrothermally altered quartzofeldspathic gneisses, granites and pegmatites of the West Garo Hills, Shillong Plateau (eastern India) preserve alteration assemblages of monazite, </span>xenotime<span> and zircon<span><span> comprising thorite and coffinite in the altered domains. </span>Albitization<span><span> of muscovite and K-feldspars, sericitization of K-feldspar and albite, alteration of </span>biotite to hydrobiotite, and crystallization of tourmaline is suggestive of the involvement of acidic fluids. The microtextural relations and the mineral assemblages indicate prevalence of low-temperature (</span></span></span></span><em>T</em><span> &lt; 300 °C) conditions during hydrothermal alteration. The light δ</span>¹¹B values of tourmaline (–15.1 to –13.5 ‰) suggests derivation/interaction of the fluids from/with metapelitic rock and/or S-type granite. Low ‘inferred’ Fe³⁺/Fe²⁺<span> ratio in tourmaline (based on high Al content in Y-site, 0.16–0.56 apfu, avg. 0.36 apfu), estimated excess charge (0.22–0.47, avg. 0.35 apfu) and lack of any Fe–Al relation support a reduced nature of the hydrothermal fluid. Mass balance calculations reveal that Th and U required for the formation of thorite and coffinite, respectively were likely derived from monazite and xenotime, and zircon. Significantly lower Cl</span>^─ contents in hydrobiotite (avg. 0.03 wt%) compared to the unaltered biotite (avg. 0.13 wt%) suggests release of Cl^─ to the hydrothermal fluid during alteration. Textural evidences of albitization together with Cl^─ release from biotite suggest increased Cl^─ concentrations in the fluid during hydrothermal alteration. Based on solubility calculations for various U and Th species, we propose that high Cl^─ content in the fluid aided mobilization of Th and U as ThCl₄⁰ and UCl₄⁰/UO₂Cl₂⁰<span> complexes from accessory radioactive phases under reducing conditions. These results suggest that significant mobility of U and Th can be achieved in acidic high salinity fluid even under reducing conditions. Thermodynamic calculations for the solubility of Th- and U-chloride complexes and stability of monazite/xenotime in a range of pH and temperature suggest that thorite and coffinite precipitation was the result of an increase in pH.</span></p></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"84 3","pages":"Article 126160"},"PeriodicalIF":2.6,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}