Chemie Der Erde-Geochemistry最新文献

{"title":"Mixed fluid processes in FeMn dendrite formation and associated carbon and nickel isotope fractionation","authors":"Anna Neubeck ,&nbsp;Piotr Szymczak ,&nbsp;Vyllinniskii Cameron ,&nbsp;Daniel Buczko ,&nbsp;Magnus Ivarsson","doi":"10.1016/j.chemer.2025.126303","DOIUrl":"10.1016/j.chemer.2025.126303","url":null,"abstract":"<div><div>Dendritic iron- and/or manganese-rich microstructures, often referred to as “microstromatolites,” are commonly observed in carbonate veins in the deep subsurface. However, the mechanisms responsible for their formation, particularly the role of microbial processes, remain incompletely understood. One hypothesis suggests that Fe- and Mn-enriched fluids, sourced from submarine hydrothermal vents and circulating through mafic or ultramafic rocks, lead to the precipitation of manganese dendrites within open fractures. Microbial activity has been proposed as a contributing factor, particularly due to its ability to catalyze Mn²⁺ oxidation to Mn⁴⁺ at rates significantly faster than abiotic processes under ambient conditions. Such microbial mediation often results in the formation of poorly crystalline Mn oxide phases, which are commonly associated with biologically mediated oxidation. These disordered Mn oxides, frequently observed in natural settings, suggest a microbial contribution to mineral precipitation, particularly in environments where redox gradients and fluid-rock interactions are prominent. Because manganese oxides are an important sink for Ni in marine systems, stable Ni isotope analyses may offer valuable insights into their formation. Biological activity in laboratory systems is known to fractionate Ni isotopes, producing negative δ⁶⁰Ni values, while abiotic interactions with Mn oxides can result in a range of isotopic signatures. In this study, we show that manganese-rich dendrites likely formed through the interplay between organic matter, oxidizing fluids and viscous serpentine muds, resulting in the fractionation of both carbon and nickel isotopes. The moderately negative δ¹³C and δ⁶⁰Ni values, together with the presence of organic matter, suggest a mixed formation pathway involving both abiotic mineral precipitation and biologically mediated processes. One plausible mechanism involves the nucleation of Mn oxides on nanoparticulate “seeds,” which could include both abiotic particles, organic matter, microbial cells and their metabolic byproducts. Understanding the formation of Fe<img>Mn dendrites is key to interpreting the biogeochemical cycling of essential elements like iron, manganese, and nickel. Due to its redox flexibility, Mn forms highly reactive oxides that effectively scavenge trace metals such as Ni, Co, Fe, and Cu, facilitating their removal from seawater and incorporation into marine minerals. Our findings underscore the complexity of Fe<img>Mn oxide formation and point to the combined influence of abiotic fluid dynamics and microbial processes. This improves our ability to interpret geochemical signatures in both modern and ancient environments and enhances the utility of stable isotope systems in reconstructing past ocean conditions and elemental cycling.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126303"},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189512","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":"Cambrian mid-ocean ridge basalt-like mafic rocks and associated boninites in the Dachadaban ophiolite from the North Qilian Block, northwest China: Petrogenesis and implications for back-arc extension","authors":"De-Chao Li ,&nbsp;Xi-Jun Liu ,&nbsp;Xiao Liu ,&nbsp;Gang Chen ,&nbsp;Qi Song ,&nbsp;Hao Tian ,&nbsp;Zheng-Lin Li ,&nbsp;Peng-De Liu ,&nbsp;Rong-Guo Hu","doi":"10.1016/j.chemer.2025.126301","DOIUrl":"10.1016/j.chemer.2025.126301","url":null,"abstract":"<div><div>The early Paleozoic Qilian Orogen is ideal for investigating ancient plate tectonic processes and can be divided into the north, middle, and south Qilian blocks. There is a consensus that North Qilian oceanic lithosphere was subducted northward beneath the Alxa Block. However, the details of this subduction in the North Qilian Ocean (e.g., whether an intra-oceanic back-arc basin was developed) are poorly constrained. In this study, we undertook petrological observations, zircon U<img>Pb geochronological and Hf isotopic analyses, and whole–rock and mineral major and trace element, and Sr<img>Nd isotopic analyses of the Cambrian (513–506 Ma) lower series mid-ocean ridge basalt (MORB)-like mafic rocks and upper series (503–490 Ma) boninites in the Dachadaban ophiolite in the North Qilian Block, northwest China. The lower series mafic rocks can be further divided into two types. Type 1 mafic rocks have uniform SiO₂ contents of 45.1–49.8 wt% and slightly enriched light rare earth element (REE) and relatively flat heavy REE patterns, similar to enriched-type MORBs. The type 2 mafic rocks and boninites have a wider range of SiO₂ contents of 49.3–59.2 and 48.1–56.6 wt%, respectively, and are depleted in light REEs and have relatively flat heavy REE patterns, similar to normal-type MORBs. In primitive-mantle-normalized element diagrams, the type 1 and 2 mafic rocks exhibit no or negligible Nb<img>Ta depletion, while the boninites exhibit obvious Nb<img>Ta depletion. The lower series type 1 and 2 mafic rocks have depleted whole-rock Nd (ε_Nd[t] = +2.6 to +6.5) and zircon Hf (ε_Hf[t] = +2.8 to +14.8) isotopic compositions, while the upper series boninites have relatively enriched Nd<img>Hf (ε_Nd[t] = +2.8 to +4.7; ε_Hf[t] = +3.4 to +13.6) isotopic compositions. We suggest that the lower series type 1 and 2 mafic rocks were formed by partial melting of garnet lherzolite (&gt;70 km depth; type 1) and spinel harzburgite (&lt;70 km; type 2) mantle sources, respectively. The upper series boninites were derived from a refractory harzburgitic mantle source that had been metasomatized by subducted-sediment-derived melts and minor slab-derived fluids. Based on these results and regional geological data, we suggest that the North Qilian Ocean experienced three stages of expansion, in the Precambrian–early Cambrian (550–520 Ma), middle–late Cambrian (513–497 Ma), and Middle–Late Ordovician (458–449 Ma). In addition, intra-oceanic subduction beneath the North Qilian Ocean and subsequent back-arc extension occurred during the middle–late Cambrian (513–490 Ma).</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126301"},"PeriodicalIF":2.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154683","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":"Formation process of a newly explored ion-adsorption type REE deposit in Pingtian, Guangdong, South China: A detailed profile analysis","authors":"Jianjun Liu ,&nbsp;Huan Li ,&nbsp;Ruilin Wang ,&nbsp;Yue Hou ,&nbsp;Shaban Godang","doi":"10.1016/j.chemer.2025.126302","DOIUrl":"10.1016/j.chemer.2025.126302","url":null,"abstract":"<div><div>Recently, ion-adsorption-type rare earth element (REE) deposits have been explored in Nanxiong Basin (South China), with an estimated total reserve of &gt;100 million tons. The formation of ion-adsorption-type deposits is closely linked to the weathered crust of their parent granitic rocks. To better understand how the weathered crust influences the formation of ion-adsorption type REE deposits, this study presents detailed research on the relationship between the characteristics of the weathered crust and parent rock in Pingtian Town, Nanxiong Basin, Guangdong Province, through a detailed profile analysis. The U<img>Pb dating of zircon and apatite indicates that the parent rock (biotite monzogranite) was formed at ca. 220 Ma, which provides favorable metallogenic conditions for the formation of the weathered crust. Minerals such as monazite, zircon, apatite, and plagioclase play critical roles in the formation of the weathered crust. Monazite and plagioclase are the main controlling minerals for REE enrichment in the weathered crust. Monazite, influenced by apatite, determines the REE distribution pattern in the crust, with a particular emphasis on light rare earth elements (LREE). Zircon, being resistant to weathering, leads to the preferential enrichment of LREE in the weathered crust and limits the accumulation of heavy rare earth elements (HREE). Plagioclase, through weathering into kaolinite, provides an adsorption medium for ionized REE. In addition, trace element analysis of zircon and apatite, as well as geochemical studies on the parent rock, indicate that the parent rock belongs to a moderately differentiated granite. The degree of granite differentiation impacts REE enrichment in the weathered crust. The higher the degree of differentiation, the more ionized REE elements and adsorption media are provided, facilitating the formation of ion-adsorption type REE deposits. This highlights the importance of detailed profile geochemical analysis in revealing the genesis of ion-adsorption-type REE deposits.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126302"},"PeriodicalIF":2.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154684","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":"Sedimentary records of tectonic background transition in the eastern Guangdong Basin in the Late Early Jurassic of the South China continental margin","authors":"Yanshen Liu ,&nbsp;Zhongjie Xu ,&nbsp;Hong Zhu ,&nbsp;Rihui Cheng","doi":"10.1016/j.chemer.2025.126297","DOIUrl":"10.1016/j.chemer.2025.126297","url":null,"abstract":"<div><div>The southeastern margin of the South China Block preserves sedimentary records of tectonic evolution controlled by Paleo-Pacific subduction. This study integrates sedimentological and detrital zircon U-Pb geochronological analyses of the Lower Jurassic Qiaoyuan Formation in the eastern Guangdong Basin. One Late Early Jurassic sample exhibits detrital zircon U-Pb ages ranging from 2317 to 187 Ma, with dominant age groups at 260–240 Ma and 1900–1800 Ma. In contrast, a terminal Early Jurassic sample shows age spectra of 2827–180 Ma dominated by a 200–180 Ma group, reflecting a transition from multi-peak to unimodal age distributions. Provenance analysis indicates that late Early Jurassic sediments (Member 1) were primarily sourced from the Jiangnan Orogen, Yunkai Terrane, and Hainan Island, while terminal Early Jurassic deposits (Member 3) originated predominantly from the Nanling Tectonic Belt. Comparative analysis of detrital zircon age characteristics in Mesozoic strata across the South China Block, incorporating similarity assessments, visualization methods, and crustal thickness estimations, demonstrates that the southeastern margin completed the transition from a compressional to extensional tectonic setting by approximately 180 Ma. This shift is chronologically constrained by provenance reorganization, basin structural transformation, and progressive crustal thinning, documenting the dynamic interplay between Paleo-Pacific subduction and intracontinental deformation.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126297"},"PeriodicalIF":2.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931566","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":"Late Neoarchean multi-stage granitoid rocks in the Dengfeng terrane, North China Craton: Petrogenesis and implications for geodynamic processes","authors":"Heng Liu ,&nbsp;Lei Liu ,&nbsp;Shuhab D. Khan ,&nbsp;Yongjun Gao ,&nbsp;Lijuan Xu ,&nbsp;Tianyang Hu ,&nbsp;Inkyeong Moon","doi":"10.1016/j.chemer.2025.126300","DOIUrl":"10.1016/j.chemer.2025.126300","url":null,"abstract":"<div><div>During the late Neoarchean era, the rise of K-rich granitoid rocks marked a significant geological event indicative of the maturation and stabilization of continental crust. These granitoids, emerging after tonalite-trondhjemite-granodiorite (TTG) magmatism, stirred debates over the interrelations and geodynamic implications. In this study, diverse granitoid rocks were identified in the Dengfeng terrane of the North China Craton (NCC), dating as approximately 2.63–2.50 Ga. The 2.5 Ga meta-dioritic rocks exhibit elevated MgO (2.2–7.7 wt%) and Mg^# (45–69). Geochemical simulation reveals sanukitoid-like pattern, featuring highly fractionated REE compositions and depleted zircon Hf isotopes (Ɛ_Hf(t) values range from +3.9 to +6.5). Apatite Nd isotopes of ε_Nd(t) values ranging from −0.1 to 4.69. Meta-dioritic rocks were interpreted to be formed by partial melting of a depleted mantle source influenced by subducted slab-derived fluids. The TTG gneiss (2.63–2.52 Ga) exhibit mildly fractionated REE patterns, weakly positive Eu anomalies, lack of magmatic fractionation evidence, and high (La/Yb)_N (6.94–114.9) and Sr/Y (28.6–294) ratios, indicating their formation derived from partial melting of pre-existing low-K mafic crust. The K-rich granitoids (2.56 Ga) are characterized by high K₂O/Na₂O ratios (0.67–1.89), low MgO content and Mg^# (&lt; 1.2 wt% and &lt; 55, respectively). A chain of evidence including geochemical modeling, constant aluminum saturation index (ASI) values of 1.00–1.35, and zircon ε_Hf(t) values ranging from +8.2 to +11.2 suggest their derivation through partial melting of tonalitic rocks. Further analysis suggests that the source for K-rich granitoids are enriched by subducted slab melts or metasedimentary rocks at various crustal depths. In terms of petrogenesis, late Neoarchean granitoid magmatism in Dengfeng terrane likely relates to subduction and accretionary orogeny. Archean active continental margins are vital for early crustal maturation and granitoid diversification during subduction and collision.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126300"},"PeriodicalIF":2.6,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068553","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":"Positive Matrix Factorization (PMF) based on geochemical data for revising geological map in semi-desert covered terrains: A case study from a map sheer of Urat Rear Banner, Inner Mongolia, China","authors":"Yanling Sun,&nbsp;Xueqiu Wang,&nbsp;Hanliang Liu,&nbsp;Jian Zhou,&nbsp;Mingjun Xie","doi":"10.1016/j.chemer.2025.126299","DOIUrl":"10.1016/j.chemer.2025.126299","url":null,"abstract":"<div><div>There is a significant deficiency for geological mapping in the Gobi Desert terrain covered by wind-blown sands with limited exposure of bedrock. Major and minor element data of stream sediments using Positive Matrix Factorization (PMF) analysis were employed to interpret the geological signatures from the Urat Rear Banner, a representative area of the Gobi Desert terrains. Six primary geochemical factors (M1, M2, M3, T1, T2, T3), corresponding to geological units were extracted from 8 major elements and 18 minor elements. Notably, the SiO₂-Al₂O₃-K₂O-and Pb-Ba-Th-Be-Y-Li-U combinations (primarily M1 and T1) are associated with felsic intrusive rocks, complex metamorphic rocks, and sandstones. The MgO-Fe₂O₃-TiO₂, Cu-Mn-Zn-Co combinations (primarily M2 and T2) indicate basic intrusive rocks, complexes. The Al₂O₃-Na₂O-CaO, Sr-Co-Mn-P-Cu-Zn-Ba (primarily M3 and T3) are related to neutral intrusive bodies (or complexes) and marble (or limestone). Additionally, the study utilizes standardized M1, M2, and M3 factor scores to refine the delineation of lithological boundaries of magmatic rocks. The findings highlight the effectiveness of the PMF method coupled with stream sediment geochemistry, as a powerful tool for extracting geological signatures. This approach offers valuable insights into geological information extraction in Gobi Desert terrains, particularly for identifying and delineating lithological boundaries within magmatic rock formations.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126299"},"PeriodicalIF":2.6,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143911632","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":"Petrogenetic and dynamic links between felsic and mafic magmas: Insights from the Devonian post-collisional magmatism in the North Qaidam terrane, western China","authors":"Denghui Chen ,&nbsp;Hao Wu ,&nbsp;Dongdong Yan ,&nbsp;Chengxiang Li ,&nbsp;Huajun Wen ,&nbsp;Fuhao Xiong","doi":"10.1016/j.chemer.2025.126298","DOIUrl":"10.1016/j.chemer.2025.126298","url":null,"abstract":"<div><div>Felsic-mafic magmatism in post-collisional settings provides valuable insights into the growth and evolution of continental crust, but the interaction processes between felsic and mafic magmatism and their implications for the diversity of igneous rocks remain controversial. This study presents petrological, geochronological, geochemical, and Sr-Nd-Hf isotopic analyses of the Mohe felsic-mafic complex, a rare post-collisional composite pluton in the North Qaidam terrane (western China), to investigate the petrogenetic and dynamic links between felsic and mafic magmas. The results reveal that the Mohe complex, consisting of granite, granodiorite, diorite, and appinites, is genetically related and formed between ca. 408–400 Ma. The granites and granodiorites are classified as I-type and are characterized by enriched isotopic signatures, including whole-rock (⁸⁷Sr/⁸⁶Sr)ᵢ values of 0.714584–0.728765, εNd_{(400 Ma)} values of −7.75 to −5.56, and zircon εHf(t) values of −3.04 to −0.28. These rocks were primarily derived from partial melting of Mesoproterozoic to Paleoproterozoic crustal materials, with minor input from a mantle source. The appinites display depleted zircon Hf isotopic compositions (εHf(t) = +4.10 to +5.71), indicating derivation from an OIB-like depleted mantle source that was metasomatized by subducted slab-derived melts. The diorites show weakly enriched isotopes ((⁸⁷Sr/⁸⁶Sr)_<em>i</em> = 0.709358–0.713210, εNd_{(400 Ma)} = −2.99 to −2.73, εHf(t) = −1.35 to +3.54), and were formed by the mixing of 80–90 % appinitic magma with 10–20 % crustal-derived granitic magma. Our findings suggest that the Early Devonian magmatism in the North Qaidam terrane was likely driven by slab break-off-related geodynamic processes, where crust-mantle magma mixing, along with mineral accumulation and fractional crystallization, played a key role in the petrological diversity of the continental crust in a post-collisional extensional setting.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126298"},"PeriodicalIF":2.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143911631","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":"Enhanced analysis of hydrothermal alteration and mineral prospecting through integration of ASTER and aeroradiometric data: A case study from the Ouarzazate region, Morocco","authors":"Ilham El Hakimi,&nbsp;Lahsen Achkouch,&nbsp;Younesse El Cheikh,&nbsp;Mohammad Taadid,&nbsp;Houda Bourouda,&nbsp;Ahmed Rachid,&nbsp;Ahmed Attou","doi":"10.1016/j.chemer.2025.126296","DOIUrl":"10.1016/j.chemer.2025.126296","url":null,"abstract":"<div><div>The study area, situated in the western segment of the Saghro Massif within the Anti-Atlas belt, is characterized by mineralized deposits, intricate lithological formations, and distinctive tectonic features. This research integrates ASTER imagery analysis with gamma-ray spectrometry data to map alteration zones and examine the geochemical and mineralogical processes that influence radioactive element distribution. Specific analytical techniques are applied to investigate relationships among argillic, phyllic, propylitic alterations, iron oxides, and regions with elevated concentrations of radiometric elements. Gamma-ray spectrometry data, including mono-elemental maps of radiometric components (potassium in %, equivalent uranium in ppm, and equivalent thorium in ppm), are analyzed alongside interpreted ASTER images to identify potential mineralization zones. Ratios of K/eU and K/eTh, along with the F parameter, are processed within a fuzzy model framework, which combines these datasets into a comprehensive mineral prospectivity map that serves as a tool for guiding exploration. This analysis identifies four hydrothermal alteration zones as highly promising for mineral exploration, suggesting a likely association between magmatic processes and spatially correlated hydrothermal alteration, thereby supporting further detailed exploration initiatives.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126296"},"PeriodicalIF":2.6,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883029","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":"Geochemistry, zircon UPb ages and Hf isotopes of Tra Bong granitoid from Kontum massif, central Vietnam, and its petrogenetic significance","authors":"Nguyen Huu Trong ,&nbsp;Pham Trung Hieu ,&nbsp;Pham Minh ,&nbsp;Bui Kim Ngoc ,&nbsp;Nguyen Dinh Luyen ,&nbsp;To Xuan Ban","doi":"10.1016/j.chemer.2025.126295","DOIUrl":"10.1016/j.chemer.2025.126295","url":null,"abstract":"<div><div>Tra Bong granitoid, distributed in the northern area of Kontum, primarily consists of diorite and granodiorite. The main rock-forming minerals contain plagioclase (26–60 %), K-feldspar (8–22 %), quartz (15–33 %), biotite (3–7 %), and hornblende (9–20 %). The accessory minerals are sphene, apatite, zircon, and magnetite. Tra Bong granitoids are characterized by SiO₂ (58.83–65.8 %), total alkali (6.68–8.03 %), and A/CNK (0.80–0.90). They show high-K and relative enrichment of large-ion lithophile elements (Sc, Rb, and K), and the relative depletion of Nb, Ta, and Ti elements. The P₂O₅ content decreases with increasing SiO₂, and Th increases with Rb, a trend typical of I-type granites. All observed petrographic and geochemical characteristics suggested that the Tra Bong granitoid is typical of the I-type granite, formed in a subduction zone. The U<img>Pb crystallization age ranges from 254.5 to 255.0 Ma, coinciding with the Late Permian-Early Triassic magmatic activity, which was previously reported in the Truong Son belt. The ε_Hf(t) value together with the Hf zircon model ages (T_DM2) ranges from 1011 to 1159 Ma. The Tra Bong granitoid is a result of partial melting Mesoproterozoic mafic-intermediate magmatic rocks, with a minor amount of metasedimentary crust remelting. In conjunction with other Permian-Triassic magmatic rocks along Truong Son belt and the Song Ma suture, the Tra Bong granitoid represents magmatic activity related to subduction-collision of the Indochina and South China blocks and closure of Paleo-Tethys Ocean in the Late Permian-Early Triassic, along the Song Ma suture.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126295"},"PeriodicalIF":2.6,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895853","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":"Identifying geochemical element distribution patterns through multiple-point geostatistical simulation and singularity analysis: A case study of the Wulonggou-Balong Area, Qinghai, China","authors":"Mengyu Zhao ,&nbsp;Qinglin Xia ,&nbsp;Wenjun Li","doi":"10.1016/j.chemer.2025.126294","DOIUrl":"10.1016/j.chemer.2025.126294","url":null,"abstract":"<div><div>The identification of geochemical element distribution patterns, the extraction of anomalies from geochemical exploration data, and the analysis of deep-level mineralization information are essential to guiding mineral prospectivity mapping. The spatial distribution of geochemical elements mainly arises from complex geological processes, making it challenging for standard deterministic interpolation techniques to capture its complex structure. In singularity analysis of element distribution, the size and geometric configuration of the sliding window significantly impact the geochemical anomaly distribution. Accordingly, this study incorporated the complex patterns extracted from multi-scale exploration geochemical data into a multiple-point geostatistical simulation framework to characterize geochemical element distributions at a fine scale. Fractal topography and singularity analysis were integrated as key analytical tools to identify and extract anisotropic geochemical anomalies. Stream sediment geochemical data from the Wulonggou–Balong area, Qinghai, China, were used as a case study to delineate gold-related geochemical spatial distribution patterns. The proposed multiple-point geostatistical (MPS) method enhanced anomaly intensity in local regions while achieving higher fidelity in reproducing spatial distribution patterns that align with regional geological trends. The spatial distribution patterns of geochemical anomalies, analyzed through diverse fractal topological relationships, highlight anisotropic characteristics in geochemical element distributions governed by ore-controlling factors. Practical application demonstrated that the methods effectively identify undetected weak anomalies associated with mineralization-favorable zones within gold geochemical distribution patterns and minimize uncertainty in anomaly interpretation.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126294"},"PeriodicalIF":2.6,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864650","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}