Acta Geochimica最新文献

{"title":"Magma heterogeneity in the generation of ophiolitic mafic rocks on the eastern flank of the Indian plate","authors":"Sashimeren Imtisunep,&nbsp;Athokpam Krishnakanta Singh,&nbsp;Monika Chaubey,&nbsp;Rajkumar Bikrmaditya Singh,&nbsp;Bendangtola Longchar,&nbsp;Shoraisam Khogenkumar,&nbsp;Amrita Dutt","doi":"10.1007/s11631-024-00755-6","DOIUrl":"10.1007/s11631-024-00755-6","url":null,"abstract":"<div><p>Subduction polarity reversal typically occurs in intra-oceanic arc settings; the existence of an ancient intra-oceanic arc and its associated back-arc system within the Neotethyan plate has been deliberated. In this study, we investigate the possible role of subduction initiation of polarity reversal in the formation of Nagaland-Manipur ophiolite (NMO), evaluate the petrological and geochronological data and compare it with the neighboring natural examples of subduction polarity reversal of the Andaman-Nicobar ophiolite (ANO). The ancient intra-oceanic arc, namely the Incertus-Woyla Arc, and its associated back-arc remnant have been correlated with the back-arc mafic of the ANO. We found that the geochemical signatures of mafic rocks of NMO and ANO are comparable, and the available geochronology data of ~ 145 Ma from the NMO basalt and chert fit well with the evolution and formation of the intra-oceanic arc, i.e., Incertus-Woyla Arc. The evolution and age of the Incertus-Woyla Arc are between 135 and 150 Ma. Although the oldest age of the ANO has been reported from metamorphic sole at about 106.4 and 105.3 Ma, the back-arc affinity of the amphibole has been credited to the back-arc spreading that occurred behind the Woyla Arc. Previous paleomagnetic and geochronological studies have suggested that the development of the back-arc basin behind the Incertus-Woyla Arc was a result of divergent double subduction. Therefore, we have inferred a similar scenario for the development of the back-arc affinity rocks of the NMO behind the Incertus-Woyla Arc and the reinterpretation for the evolution of the supra-subduction zone affinity rocks of NMO and ANO during subduction initiation after subduction polarity reversal.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"784 - 804"},"PeriodicalIF":1.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171622","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":"Petrography and geochemistry of the Dupi Tila formation: Implications for depositional environment and tectonics","authors":"Ummae Habiba Sultana,&nbsp;Md Shofiqul Islam,&nbsp;Yesmin Nahar Jolly,&nbsp;K. M. Mamun,&nbsp;Shirin Akter,&nbsp;Muhammad Omar Faruk,&nbsp;Maliha Anzuman,&nbsp;Md Masud Karim","doi":"10.1007/s11631-024-00754-7","DOIUrl":"10.1007/s11631-024-00754-7","url":null,"abstract":"<div><p>A comprehensive examination of detrital sandstone modes from the Sylhet Trough reveals a diverse range of sub-lithic to sub-feldspathic quartz arenites. Soil samples were gathered from Dupi Gaon (Jaintiapur) in Bangladesh, followed by a thorough analysis using field examination, X-ray diffraction (XRD), X-ray fluorescence (XRF), petrography, and heavy mineral concentration analyses. Field observations revealed the soil sample varying from white to yellowish to variegated, with thicknesses ranging from 15 cm to about 4 m, and exhibiting moderate softness. XRF analysis revealed significant SiO₂, Al₂O₃, and Fe₂O₃ levels in the samples, with zirconium (Zr) and copper (Cu) showing consistently high concentrations. XRD analysis identified quartz as predominant, along with muscovite, biotite, and accessory minerals like rutile and magnetite. Petrographic analysis highlighted quartz as dominant, with fractures suggesting tectonic influences, while heavy mineral separation techniques identified zircon, garnet, goethite, rutile, and magnetite. These findings provide insights into sediment provenance, depositional processes, and environmental conditions during the formation of the Dupi Tila Formation. The comprehensive geochemical data of the entire rock indicates that most of the sediments originated from felsic igneous sources, and also suggests a moderate to high level of weathering in the source region. Overall, the analyses suggested an in situ origin of the Dupi Tila Formation, with parent materials being predominantly detrital rather than authigenic, supported by the presence of detrital quartz and an assessment of the depositional environment, providing insights into the geological conditions of the era and potential modes of sediment transportation.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"740 - 758"},"PeriodicalIF":1.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167583","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 U–Pb geochronology of the granite porphyry in Bainiuchang, Southeastern Yunnan, China","authors":"Nan Shi,&nbsp;Jun Zhu,&nbsp;Xuelong Liu,&nbsp;Shitao Zhang,&nbsp;Guangzhi Meng,&nbsp;Hong Zhang,&nbsp;Jialong Cheng,&nbsp;Jiehu Zhou,&nbsp;Bode Lu,&nbsp;Junshan Dao,&nbsp;Xue Mi,&nbsp;Maohuang Fan","doi":"10.1007/s11631-024-00750-x","DOIUrl":"10.1007/s11631-024-00750-x","url":null,"abstract":"<div><p>The Bainiuchang Ag-polymetallic ore deposit, located in southeastern Yunnan, China, is one of the region’s largest deposits. However, the hypabyssal granite porphyry within this mining area has yet to be comprehensively investigated. In this study, we conducted geochemical, geochronological, whole-rock Sr–Nd isotope, and zircon Hf isotope analyses on granite porphyry samples collected from the Bainiuchang deposit. The results indicate that the granite porphyry formed between 87.5 and 87.4 Ma in the Late Yanshanian period. Geochemically, the granite is strongly peraluminous, with high silica and alkali contents consistent with S-type granite characteristics. The granite porphyry is enriched in large-ion lithophile elements (Rb, Th, U, and K) and is relatively depleted in Ba and Sr. The initial ⁸⁷Sr/⁸⁶Sr ratios are high (0.71392–0.71585), accompanied by low <i>ε</i>_Nd(<i>t</i>) values (− 8.9 to − 8.2). The zircons exhibited similarly low <i>ε</i>_Hf(<i>t</i>) values (− 9.31 to − 3.6). These data suggest that the porphyry-forming magma originated from a continental crustal source. The two-stage Hf and Nd model ages are estimated at 1534–1216 Ma and 1615–1561 Ma, respectively. Thus, the granite porphyry likely formed under a strike-slip extensional setting in the Late Yanshanian period and resulted from the re-melting of Proterozoic basement metagreywackes. This porphyry shares a similar magmatic origin with concealed granite bodies within the deposit and is associated with structural reactivation during the Yanshanian. The findings of this study provide valuable insights into the tectonomagmatic mineralization processes in the Bainiuchang area.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 2","pages":"325 - 347"},"PeriodicalIF":1.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical characteristics of quaternary sediments in the St. Martin Island, Bangladesh: implication for provenance, weathering and sedimentary processes","authors":"Rahat Khan,&nbsp;Sudeb Chandra Das,&nbsp;Ayon Saha,&nbsp;Khondaker Md. Nur Alam,&nbsp;Abdullah Al-Amin,&nbsp;Saad Aldawood,&nbsp;Md. Abu Haydar,&nbsp;Sudipta Saha,&nbsp;Md. Masud Karim,&nbsp;Md. Harunor Rashid Khan,&nbsp;Abubakr M. Idris,&nbsp;A. H. M. Saadat,&nbsp;Dhiman Kumer Roy","doi":"10.1007/s11631-024-00742-x","DOIUrl":"10.1007/s11631-024-00742-x","url":null,"abstract":"<div><p>The sedimentary geochemistry of St. Martin’s Island is important to determine the origin of the source rock, paleo weathering, tectonic setting, sediment recycling, maturity, sorting, redox condition, and paleo salinity of the sediments. Major oxides, trace elements, and rare earth elements (REEs) obtained from the INAA technique are presented by analyzing the sediment samples collected from the shoreline of St. Martin’s Island, Bangladesh. The elemental ratios, comparison with average upper continental crust (UCC), binary diagrams (Th/Sc vs. Sc, La/Th vs. Hf, Th/Co vs. La/Sc), and chondrite normalized REE patterns exhibit substantial LREE enrichment, relatively flat HREE fractionation, considerable negative Eu anomalies (average: 0.72), indicates the derivation from a source dominated by felsic rock, with contribution from intermediate source and mafic component. Sediments from St. Martin’s Island exhibit the deposition of sediments in transitional environments of active and passive continental margin settings. Weathering indices value of CIA, PIA, CIW, CIX, and K₂O/Rb ratio show moderate chemical weathering, indicating that the sediments are chemically mature. Sedimentary redox indicative proxies, such as U/Th, V/Cr, and V/Sc, show an oxic depositional environment during sediment deposition. The intermediate CIA and other weathering index values of the St. Martin’s sediments show that the area had semiarid and humid climatic conditions throughout the deposition. The Rb/K ratio of the St. Martin’s sediments suggests that the development and deposition of the sedimentary sequence of St. Martin’s Island mainly occurred in a brackish water environment during the geological past.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 3","pages":"573 - 598"},"PeriodicalIF":1.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143880","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":"Lithium-rich tourmaline in Himalayan leucogranite: An example from the Gabo Li-rich granite-pegmatite system, Xizang, China","authors":"Hongzhao Shi,&nbsp;Yiyun Wang,&nbsp;Linkui Zhang,&nbsp;Hong Liu,&nbsp;Weikang Guo,&nbsp;Jiangang Fu","doi":"10.1007/s11631-024-00753-8","DOIUrl":"10.1007/s11631-024-00753-8","url":null,"abstract":"<div><p>The Gabo lithium deposit represents a newly discovered pegmatite-type lithium deposit within the Himalayan metallogenic belt. The tourmaline-muscovite granite, the largest leucogranite in the mining area, displays a close spatial correlation with the Li-pegmatite veins. This study aims to examine the genesis of tourmaline and evaluate the significance and potential of pegmatite lithium deposits. Tourmaline is extensively distributed in tourmaline-muscovite granite at Gabo deposit in Luozha county (Xizang). Investigation of the compositional and in situ boron isotopes of the tourmaline revealed that the tourmalines mainly belong to the schorl group and exhibit uniform elevated Li–Sn contents and <i>δ</i>¹¹B values (− 11.6 ‰ to − 10.5‰). This indicates that the tourmaline mainly crystallized from a boron-rich granitic magma undergoing enrichment in elemental lithium during the tourmaline crystallization process. Compared with the principal rare metal leucogranite-pegmatites in the Himalayan orogen, it is proposed that the elevated lithium (Li) content of tourmaline serves as an effective mineral indicator for the highly evolved pegmatite-type rare metal deposits.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 2","pages":"297 - 313"},"PeriodicalIF":1.4,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749075","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":"Mineralogical and elemental geochemistry constraints on provenance evolution of sediments in the lower reaches of the Shichuan River, Shaanxi Province, China","authors":"Caixia Feng,&nbsp;Shen Liu,&nbsp;Chenhui Hou,&nbsp;Wenlei Song,&nbsp;Ian M. Coulson","doi":"10.1007/s11631-024-00751-w","DOIUrl":"10.1007/s11631-024-00751-w","url":null,"abstract":"<div><p>The Shichuanhe River, a major tributary of the lower Weihe River, is situated in Xi’an, Shaanxi Province, China. It holds significant information regarding the evolution of the Northern Weihe River, making its study crucial for understanding environmental changes in the region. Despite its importance, research on the Shichuanhe River basin has thus far been primarily focused on riverbank construction, with limited exploration of its sediment characteristics. Although river sediments hold potential for guiding agricultural practices in the area, comprehensive studies on their composition and provenance remain scarce. To address this gap, a systematic sediment sampling campaign was conducted in the lower reaches of the Shichuanhe River, and detailed mineralogical analyses were performed. The results show that the sediment is predominantly composed of detrital quartz and feldspar (albite and orthoclase), with heavy minerals constituting approximately 10%–12% of the total sediment volume. The analysis of the heavy mineral assemblage reveals an absence of significant contributions from igneous rocks in the sedimentary profile. Furthermore, the distribution patterns of major, trace, and rare-earth elements in the Shichuanhe River’s argillaceous sediments exhibit similarities to those found in the Weihe River’s sediments. Elemental fractionation patterns suggest that the Shichuanhe River sediments are primarily derived from Loess Plateau sediments, aligning with findings from both the Weihe River and the middle reaches of the Yellow River.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 3","pages":"441 - 460"},"PeriodicalIF":1.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142898","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":"Stable strontium isotope fractionation during crystal-melt separation in granitic magma evolution","authors":"Xuqi Chen,&nbsp;Gengxin Deng,&nbsp;Dingsheng Jiang,&nbsp;Xiaoyun Nan,&nbsp;Fang Huang","doi":"10.1007/s11631-024-00752-9","DOIUrl":"10.1007/s11631-024-00752-9","url":null,"abstract":"<div><p>Stable Sr isotopic composition (δ^88/86Sr) can be used to study magmatic processes, but their fractionation mechanism during magmatic evolution remains unclear. To understand the fractionation behaviors of the stable Sr isotopes during magmatism, we report the δ^88/86Sr values of the Huili granitic pluton, which was subjected to intensive crystal-melt separation. The Huili pluton consists of K-feldspar granite and more evolved albite granite, and the albite granite exhibits significantly higher δ^88/86Sr values (+ 0.36‰ to + 0.52‰) than that of K-feldspar granite (+ 0.11‰ to + 0.25‰). K-feldspar, which contributes most of the Sr budget of the K-feldspar granite, has slightly lower δ^88/86Sr values (− 0.01‰ to + 0.17‰) than the whole rock. The δ^88/86Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals, because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt. Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction, reflecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt. This study indicates that melt extraction plays a key role in granitic magma evolution.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"731 - 739"},"PeriodicalIF":1.3,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163491","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 of the Jaisamand sanukitoids and associated TTGs: Constraints on the Neoarchean tectonic evolution of the southern Aravalli-Banded Gneissic Complex, northwest India","authors":"Prabhakar Dutta,&nbsp;Parampreet Kaur,&nbsp;Naveen Chaudhri,&nbsp;Swati Sharma","doi":"10.1007/s11631-024-00749-4","DOIUrl":"10.1007/s11631-024-00749-4","url":null,"abstract":"<div><p>The lack of a comprehensive whole-rock geochemical and mineralogical dataset for the Archean granitoids of the Aravalli-Banded Gneissic Complex (BGC), northwest India, results in significant challenges for their correct characterization and assessment of their antiquity. The new field, mineralogical and geochemical data classify the Jaisamand granitoids into sanukitoids, TTGs, and transitional TTGs, which are most likely coeval in nature. The obtained results, in conjuncture with the previously published geochemical and geochronological results of the Aravalli–BGC granitoids, unveil the Neoarchean affinity of the Jaisamand pluton. The TTGs were generated by the melting of a subducting slab (metabasite) at shallow (high-HREE-Y TTGs) to moderate depths (medium-HREE-Y TTGs) above the garnet-in line but still within the plagioclase stability field, with garnet-poor residue. The ascending TTG melts were transformed into sanukitoids through differential interaction with the overlying mantle wedge peridotite. The TTG melts, generated at different pressures, interacted with older TTGs at lower and middle crustal levels to form the transitional TTGs. The coexistence of high-HREE-Y and medium-HREE-Y TTGs and sanukitoids suggests a subduction-related setting for the Jaisamand granitoids. The heat required for simultaneous melting at shallow and deeper depths during the Neoarchean was provided by the upwelling asthenosphere due to slab break-off. The study also revealed the occurrence of altered granitoids in the Jaisamand pluton, showing evidence of albitization and silicification. These rocks do not represent the pristine mineralogy and should be carefully examined to avoid misleading interpretations, particularly for the Archean granitoids.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"700 - 730"},"PeriodicalIF":1.3,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169840","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 geodynamics of the Dashenshan I-type granite and its implications for the Triassic tectonic evolution of the South China Block","authors":"Zhen Xi,&nbsp;Yang Zhang,&nbsp;Zhennan Liu,&nbsp;Huan Li,&nbsp;Fenliang Liu","doi":"10.1007/s11631-024-00748-5","DOIUrl":"10.1007/s11631-024-00748-5","url":null,"abstract":"<div><p>There is significant debate concerning the tectonic characteristics and evolutionary understanding of the South China Block (SCB) during the Early Mesozoic. One of the key points of contention is the tectonic–magmatic activity during the Triassic and its dynamic mechanisms. However, research on the detailed chronology and tectonic settings of granite plutons in key regions remains insufficient, limiting the understanding of the tectonic–magmatic dynamic mechanisms in the interior of SCB during the Triassic. In this contribution, we present whole-rock major and trace elemental data, Sr–Nd isotope data, LA-ICP-MS zircon U–Pb age dating, and Lu–Hf isotope data for granites of Dashenshan pluton in the Xiangzhong, northwest part of SCB. The results indicate that the Dashenshan granite has an emplacement age of 208.4–212.5 Ma, characterized by high SiO₂, Na₂O, and K₂O contents and low MgO and CaO. The Dashenshan granite is enriched in light rare-earth elements with a significant negative Eu anomaly (average <i>δ</i>Eu = 0.42). It is also enriched in Rb, K, and Th and shows pronounced depletion in Nb, Ta, and Ti, classifying it as peraluminous calc-alkaline granite, specifically of the I-type. The zircon <i>ε</i>_Hf(<i>t</i>) values range from − 8.39 to − 4.4, with an average of − 5.82, and the Sr–Nd isotopes are relatively enriched [<i>ε</i>_Nd(<i>t</i>) = − 9.31 to − 6.8]. Combining these geochemical characteristics, it is revealed that the Dashenshan granite was derived from the partial melting of middle to upper crustal metamorphic basement materials under medium- to low-temperature conditions, with possible minor contributions from mantle-derived materials. Furthermore, it underwent fractional crystallization, including plagioclase differentiation. By integrating the geochemical features and spatial distribution of Triassic granites in SCB, this study suggests that the regional tectonic evolution of SCB during the Triassic was primarily controlled by the collision of the SCB with the Indochina Block and the North China Block. In Xiangzhong, the tectonic setting transitioned from syn-collisional compression to post-collisional extension during the Late Triassic. The Dashenshan pluton formed in a post-collisional extensional setting, resulting from the decompression melting of middle-to-upper crustal rocks. The upwelling of the asthenosphere and upward heat transfer likely played a significant role in the formation of the Dashenshan granitic magma.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"673 - 699"},"PeriodicalIF":1.3,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145164933","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":"Genesis of the Jiuqu gold deposit, Jiaodong gold province, China: Constraints on the texture, mineral geochemistry, and sulfur isotope of pyrite","authors":"Senmiao Xue,&nbsp;Yayun Liang,&nbsp;Lei Shu,&nbsp;Wenhao Xue,&nbsp;Chenxi Zhang,&nbsp;Chonghui Shen,&nbsp;Bi He,&nbsp;Haiyi Wang,&nbsp;Yayi Fang","doi":"10.1007/s11631-024-00747-6","DOIUrl":"10.1007/s11631-024-00747-6","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province, China, with over 1000 tons of gold resources. Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars, a definitive conclusion remains elusive. The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field, characterized as a quartz vein-type gold deposit. Gold mineralization in the Jiuqu gold deposit is classified into four stages, primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite. Pyrite, the primary gold-bearing mineral at the Jiuqu Gold Mine, has been present throughout the metallogenic period, is rich in a variety of trace elements and is closely related to the formation of gold ore. This study focused on evaluating pyrite from the essential metallogenic stages (Stages I–III) of the Jiuqu gold deposit using scanning electron microscopy (SEM), electron microprobe analysis (EMPA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) sulfur isotope analysis and detection. The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit. Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages. The aforementioned stages can be delineated as follows: type 1 pyrite (PyI), developed in the initial ore stage, is characterized by coarse-to-medium-grained euhedral pyrite in Stage I; type 2 pyrite (PyII), developed in the second ore stage, appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite; type 3 pyrite (PyIII), developed in the third ore stage, primarily occurred in the late-middle stages of mineralization. It is fragmented and coexists with various metal sulfides, including chalcopyrite, sphalerite and galena. The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au, in the form of visible gold, exists in pyrites with low Au and Ag contents throughout all stages. PyI had lower Pb, Bi, Co and Ni contents than those of PyII. PyIII displayed decreased Pb, Bi, Co and Ni levels compared with PyII. The δ&lt;sup&gt;34&lt;/sup&gt;S values of the PyI, PyII and PyIII pyrite stages ranged from 7.19% to 8.71%, 6.24% to 7.68% and 7.66% to 8.07%, respectively. According to the structural and geochemical analysis of pyrite, the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma, mixing S from Precambrian metamorphic rocks. Previous studies on the H–O isotopes of quartz in the region's ores have indicated the presence of primary magma ","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 3","pages":"631 - 647"},"PeriodicalIF":1.3,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145142957","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}