Ore Geology Reviews最新文献

{"title":"Sulfide trace element enrichments in the metamorphic basement-hosted Xinhua Pb-Zn-Cu vein-type deposit, eastern Guizhou province (SW China)","authors":"Zhenzhong Xiang , Lin Ye , Chen Wei , Tao Wu , Shiyu Liu , Yusi Hu , Zhilong Huang , Sichen Liu , Minghong Zheng , Lin Du","doi":"10.1016/j.oregeorev.2024.106280","DOIUrl":"10.1016/j.oregeorev.2024.106280","url":null,"abstract":"<div><div>Cambrian carbonate formations are widespread in the western Hunan-eastern Guizhou region (southwestern China), which hosts many Mississippi Valley-Type (MVT) lead–zinc (Pb-Zn) deposits. Regional Pb-Zn mineralization is well developed in the low-grade metamorphic rocks of the basal Proterozoic Banxi Group. The mineralization is associated with quartz veins and generally distributed along NE-trending fault zones. Moreover, these deposits have an extensive distribution and high grade, and are associated with Cu-Ag endowment. However, geological and geochemical research on these Pb-Zn vein-type deposits is relatively limited, and their relationship with the regional MVT mineralization remains unclear. The representative Xinhua deposit in Danzhai district is selected as the study subject. We conducted in situ trace element analyses on the sphalerite and chalcopyrite from the various metallogenic stages, and compared them with published sphalerite trace element data from the MVT Pb-Zn deposits in the western Hunan-eastern Guizhou metallogenic belt. Seven orebodies in Xinhua Pb-Zn deposit have been discovered so far, with a metal resource of over 120,000 metric tonnes of Zn + Pb. Field geology and microscopic petrography have revealed two mineralization stages: An early-stage black sphalerite (Sp-I) followed by reddish-brown sphalerite (Sp-II) mineralization, which corresponds to the main chalcopyrite mineralization stage, and a later-stage light-yellow sphalerite (Sp-III), Cu ore-barren mineralization.</div><div>LA-ICPMS data indicate that the sphalerite from Xinhua has similar trace element compositions to those from the MVT Pb-Zn deposits in the region. They are relatively enriched in Ga, Cd, and Ge, while depleted in Fe, Co, and Mn. Critical metal Ge and Ga are particularly enriched in sphalerite, especially in Sp-I (Ge max 937 ppm, Ga max 824 ppm). The substitution mechanism of Ge and Ga in sphalerite are likely 2Cu<sup>+</sup> + Ge<sup>4+</sup> ↔ 3Zn<sup>2+</sup> and Cu<sup>+</sup> + Ga<sup>3+</sup> ↔ 2Zn<sup>2+</sup>. Indium and Sn are mainly present in Sp-I and Sp-III. Chalcopyrite contains Zn and Sn both exceeding 100 ppm. Contents of Se, Ag, In, and Sn in chalcopyrite are significantly higher than those in sphalerite. Calculation of the sphalerite trace element geothermometer (GGIMFis) suggests that the average sphalerite ore-forming temperatures are 164 °C (Sp-I), 156 °C (Sp-II), and 205 °C (Sp-III), implying medium- to low-temperature mineralization. This indicates a possible influx of high-temperature, in-bearing fluid during the late-stage mineralization.</div><div>In summary, the faults-controlled vein-type Pb-Zn deposits (e.g., Xinhua) may have been products of the same Kwangsian orogeny as other strata bound MVT deposits, and the Xinhua deposit features two mineralization stages with multiple ore metal sources. During the ore-forming fluid ascent, some ore-forming materials may have precipitated in the fluid conduits. And expo","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535072","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":"Replacive IOCG systems in the Ossa Morena Zone (SW Iberia): The role of pre-existing ironstones as a geochemical trap","authors":"Fernando Tornos , Carmen Conde , David Rodriguez , Dolores García , John M. Hanchar , Jesús García Nieto , Gonzalo Ares , Tobias E. Bauer , Luis Rodriguez Pevida","doi":"10.1016/j.oregeorev.2024.106259","DOIUrl":"10.1016/j.oregeorev.2024.106259","url":null,"abstract":"<div><div>The central Ossa Morena Zone (SW Iberia) hosts a regionally extensive ironstone level interbedded with bimodal volcanic rocks, limestone and shale of Lower-Middle Cambrian age. The stratabound ironstone includes dominant magnetite and hematite with locally abundant chert and barite. It is interpreted as being (sub-)exhalative at or near the seafloor and formed during a rifting event that postdated the Cadomian orogeny. In some places, such as in the Las Herrerías deposit, the ironstone is irregularly replaced by a chalcopyrite-rich ore; the Cu-rich mineralization is accompanied by the pervasive phyllic alteration of the hosting siliciclastic sediments. The highest copper grades are found when the ironstone is crosscut by WNW-ESE-trending late-Variscan extensional brittle-ductile structures that are interpreted as the feeder channels for deep hydrothermal fluids. A similar nearby copper-rich mineralization (Pallares) is likely controlled by the tectonic contact between limestone and pyrite-rich black shale.</div><div>Sr-Nd whole-rock isotope geochemistry data suggests that the Sr in the ironstone (<sup>87</sup>Sr/<sup>86</sup>Sr<sub>i</sub> ≈ 0.7088) is close to isotopic equilibrium with the local exhalative barite (0.7084–0.7086) and Cambrian seawater. The ironstone has a significantly more crustal εNd initial signature (<-1.8) than the coeval volcanic rocks (+5.2 to + 7.9). The younger sulfide mineralization inherited the Nd isotope composition of the ironstone but shows a significant enrichment in <sup>87</sup>Sr (<sup>87</sup>Sr/<sup>86</sup>Sr > 0.7091) that is interpreted as related with the input of genetically different and more crustally-derived hydrothermal fluids.</div><div><sup>39</sup>Ar-<sup>40</sup>Ar dating of the phyllic alteration suggest that the copper mineralization was formed at ca. 332–330 My. These ages are coeval with those of small peraluminous granite intrusions that host Cu-Au vein-like mineralization and dated at 331.8 ± 1.6 Ma (LA ICPMS U-Pb zircon). Our interpretation is that the copper-rich mineralization at the Las Herrerías area is the distal expression of an intrusion-related hydrothermal system.</div><div>Numerical modelling shows that ironstone is an effective trap for copper precipitation due to the large changes in pH and <em>f</em>O<sub>2</sub> that take place when copper-bearing acid and reduced fluids react with the brittle ironstone. The precipitation of chalcopyrite, however, is controlled by the amount of available reduced sulfur in the ore trap. The δ<sup>34</sup>S values of the sulfides (+12.6 to + 21.6 ‰) suggest that the most likely source for the reduced sulfur is the thermogenic reduction of aqueous sulfate equilibrated with the exhalative barite (δ<sup>34</sup>S, +31.4 to + 35 ‰) with some minor input of reduced sulfur leached from the metasediments.</div><div>This system could be considered as a variant of the IOCG clan. The formation of the ironstone and the copper mineralizatio","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535071","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":"Cassiterite and zircon U-Pb ages and compositions from ore-bearing and barren granites in Thailand: Constraints on the formation of tin deposits in Southeast Asia","authors":"Liang Liu ,&nbsp;Rui-Zhong Hu ,&nbsp;Ya-Zhou Fu ,&nbsp;Jie-Hua Yang ,&nbsp;Mei-Fu Zhou ,&nbsp;Wei Mao ,&nbsp;Yan-Wen Tang ,&nbsp;Alongkot Fanka ,&nbsp;Zhen Li","doi":"10.1016/j.oregeorev.2024.106282","DOIUrl":"10.1016/j.oregeorev.2024.106282","url":null,"abstract":"<div><div>The Southeast Asian Tin Province comprises western, central, and eastern belts and hosts significant granite-related Sn deposits. The genetic links between granites and Sn mineralization are still unclear. Most Sn deposits are in Thailand’s western and central belts, but their origin remains poorly elucidated due to the absence of direct dating of mineralization. Herein in-situ U-Pb age data of wolframite and cassiterite grains from nine representative Sn deposits in Thailand are obtained, which fall into two stages. Triassic deposits (224–210 Ma) are found in the Central belt, with Cretaceous deposits (78–67 Ma) in the Central belt being younger than those in the Western belt (84–74 Ma). However, ore-bearing granites, spanning two periods (227–205 Ma and 85–69 Ma), occur in central and western belts. Some Triassic ore-bearing granites exhibit significantly older ages than ore-forming ages. Newly identified ore-forming granites contain zircon grains with relatively low ε_Hf(<em>t</em>) values (−29.5 to + 4.1; average =  − 11.8), indicative of an origin from supracrustal sediments from the Sibumasu block. In contrast, barren granites have ages from 303–224 Ma and higher zircon ε_Hf(<em>t</em>) values (−9.9 to + 13.2; average = +1.2), which suggests that they were derived from the juvenile mafic crust. Even after experiencing hydrothermal fluids exsolution, some low-fractionated ore-forming granites (D.I. &lt; 90) still maintain remarkably high tin contents. Both ore-forming and barren granites crystallized under reducing conditions. Our study highlights the importance of Sn-rich sources of parental magmas in forming Sn deposits. The metasediment-rich basement of the Sibumasu block distributing along the continental margin is likely the Sn-rich source. These sources played a crucial role in forming two stages of tin deposits in distinct tectonic settings, that are <em>syn</em>-collisional crustal thickening in Paleo-Tethys and post-collisional extension-related settings in Neo-Tethys.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441124","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":"Formation of the Lianhuashan Cu deposit in the southern Great Xing’an Range, NE China: Constraints from fluid inclusions, whole-rock geochemistry, zircon U–Pb geochronology, and H–O–S–Pb isotopes","authors":"Xue-li Ma ,&nbsp;Kai-tuo Shi ,&nbsp;Ke-yong Wang ,&nbsp;Chun-kit Lai ,&nbsp;Rui Wang","doi":"10.1016/j.oregeorev.2024.106283","DOIUrl":"10.1016/j.oregeorev.2024.106283","url":null,"abstract":"<div><div>The medium-sized Lianhuashan Cu sulfide deposit is located in the southern Xing’an Range of Inner Mongolia, NE China. The zoned massive sulfide vein ores are hosted mainly in the Permian Dashizhai Formation, and the ore veins are controlled by NW–NNW-trending structures. The ore-forming process comprises four stages: arsenopyrite–quartz (I); chalcopyrite–pyrite–quartz (II); pyrite–chalcopyrite–sphalerite–galena–quartz (III); and ore-barren sulfide–quartz–carbonate (IV). Three types of fluid inclusions (FIs), namely vapor-rich two-phase (LV-type), liquid-rich two-phase (VL-type), and daughter mineral-bearing three-phase (SL-type), are distinguished. Stage I, II and III contain all types of FIs (LV-, VL-, and SL-type), with homogenization temperatures (Th) of 268–462°C, 230–382°C and 180–340°C and salinities of 3.4–52.3, 3.4–44.5 and 3.7–39.9 wt% NaCl eqv., respectively, whereas stage IV has only VL-type FIs, with Th = 152–232°C and salinity = 3.4–7.9 wt%. Fluid geochemical data show that the Lianhuashan ore fluids were of medium–high temperature (236–382 °C), high-salinity (31.5–44.5 wt%), and relatively oxidizing conditions, typical of a NaCl-H₂O system. The microthermometric and H–O isotope data (δ¹⁸O_H2O =  − 9.0 to 6.1 ‰; δD =  − 149.0 to − 99.0 ‰) indicate that the ore fluids were initially magmatic with later meteoric water incursion. The sulfide S (δ³⁴S =  − 2.9–3.8 ‰) and Pb (²⁰⁶Pb/²⁰⁴Pb = 17.954 − 18.492, ²⁰⁷Pb/²⁰⁴Pb = 15.427 − 15.739, ²⁰⁸Pb/ ²⁰⁴Pb = 37.815 − 38.357) isotopes support that the metals were magmatic-derived. Fluid boiling, cooling, and meteoric water mixing were likely the main ore precipitation mechanism at Lianhuashan.</div><div>We suggest that Cu minerals at Lianhuashan were precipitated with boiling at ∼ 1<!--> <!-->km depth. For the ore-forming granodiorite porphyry (zircon U-Pb age: 252.8 ± 1.8 Ma), geochemical data indicate that the primary magma was formed by partial melting of the thickened or delaminated lower crust. Integrating the available age, geological, and geochemical evidence, we suggest that mineralization at Lianhuashan is spatial–temporal and genetically associated with the granodiorite porphyry, and was formed in a volcanic arc setting after the Paleo-Asian Ocean closure.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444760","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":"Distribution and enrichment processes of cobalt in the Longqiao iron skarn deposit in Eastern China","authors":"Yifan Zhang ,&nbsp;Yu Fan ,&nbsp;Yinan Liu ,&nbsp;Taofa Zhou ,&nbsp;Bangguo Ou","doi":"10.1016/j.oregeorev.2024.106277","DOIUrl":"10.1016/j.oregeorev.2024.106277","url":null,"abstract":"<div><div>Longqiao is a cobalt-rich skarn iron deposit in Eastern China. As a typical representative of its type, it provides an opportunity to study the occurrence, distribution, and factors controlling cobalt in these deposits. Cobalt-bearing ores in Longqiao deposit can be classified into two types: cobalt-bearing diopside-magnetite ore (Co-Di-Mag) and cobalt-bearing phlogopite-magnetite ore (Co-Phl-Mag). Systematic whole-rock geochemical analysis, automated mineral analysis (TESCAN Integrated Mineral Analyzer, TIMA), and LA-ICP-MS trace element analysis were conducted on the two ore types. Three independent cobalt minerals（cobaltite, glaucodot, and carrollite）were found in Co-Di-Mag; no independent cobalt minerals were found in Co-Phl-Mag. TIMA and LA-ICP-MS analyses showed that cobalt in Co-Phl-Mag is mainly hosted in pyrite, so the pyrite content has a decisive role in the overall cobalt content. Cobalt in Co-Di-Mag is controlled by the content of magnetite, pyrite, and cobalt minerals.</div><div>In both the diopside-magnetite stage (Stage I) and phlogopite-magnetite stage (Stage II), the cobalt mainly occurs in magnetite, and its content gradually decreases from 80 to 30 ppm as the system evolved. During the sulfide stage, minor pyrite deposited near the intrusion, and cobalt occurs in the pyrite lattice and also forms numerous independent cobalt minerals. Pyrite is abundant in the distal part of the ore-body, where all cobalt occurs in pyrite, and independent cobalt minerals are absent.</div><div>Cobalt mainly occurs in pyrite in Longqiao deposit, which is favorable for beneficiation and recovery. Similar skarn iron deposits are widespread in eastern China, and the cobalt in these deposits has potential for recovery.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444746","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":"Mineralization processes in the Bainaimiao Cu-Au deposit in Inner Mongolia, China: Constraints from geology, geochronology, and mineralogy","authors":"Changhao Li ,&nbsp;Ping Shen ,&nbsp;Branimir Šegvić ,&nbsp;Pei Li ,&nbsp;Chong Cao ,&nbsp;Ge Ma ,&nbsp;Qingyu Suo ,&nbsp;Haoxuan Feng ,&nbsp;Xiangkai Chu","doi":"10.1016/j.oregeorev.2024.106276","DOIUrl":"10.1016/j.oregeorev.2024.106276","url":null,"abstract":"<div><div>The Central Asian Orogenic Belt underwent complex tectonic processes and is one of the most intensely accretionary areas globally. Porphyry copper deposits within the belt were likely subjected to deformation during tectonic processes. The Bainaimiao Cu-Au deposit is a typical example of a deformed porphyry deposit whose formation processes include a porphyry emplacement (Event I), a greenschist facies metamorphism (Event II), and a brittle deformation (Event III). Geochronology and trace element geochemistry of zircon, volatiles of magmatic apatite, along with the assemblages, textures, abundances, and compositions of phyllosilicates from these three events were investigated to unveil the physicochemical conditions under which the key geological events relevant to the deposit formation took place. LA-ICP-MS zircon U-Pb dating shows that the granodiorite porphyry in the northern and southern zones formed at 447.4 ± 1.6 to 445.8 ± 3.6 Ma and 436.1 ± 3.8 to 434.1 ± 3.3 Ma, respectively. The granodiorite porphyry in the northern zone has higher oxygen fugacity and Cl_melt content but similar S_melt and F_melt contents compared to the granodiorite porphyry in the southern zone. Microscopic and mineralogic observations point to Event I to be of high plagioclase (22–67 vol%) and quartz (6–40 vol%) content with a range of hydrothermal minerals related to potassic, phyllic, and propylitic alterations. Event II features high amphibole (38–83 vol%) or epidote-chlorite (up to 77 vol%) content with minerals precipitating along the schistosity planes. Event III is characterized by wide veins (3–80 cm) and the highest quartz (61–65 vol%) and calcite (12–19 vol%) content. Geothermometry results show the temperature of potassic and phyllic alterations of Event I to be ∼622 °C and ∼288 °C, respectively. Based on geothermometry and <em>P-T</em> pseudosections, the temperatures of metamorphism and metallic precipitation of Event II were ∼271–634 °C and 297–328 °C, respectively. Both mechanical and chemical mobilization of metallic elements results in Cu mineralization during Event II. The metallic precipitation temperatures of Event III spanned from 297 to 328 °C according to chlorite geothermometry. The ratios of Fe³⁺/Fe_total and Mg/(Mg + Fe_total) of biotite, chlorite Fe/(Fe + Mg), and white K-mica composition show the mineralizing fluid of Event III to be the most oxidized while that of Event II is the most reduced, F-rich and features the lowest water/rock ratio. This study suggests that deformation processes can increase the Cu mineralization grade of the deformed porphyry deposits through mobilization and re-precipitation of metallic elements.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437638","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":"Pyrite in-situ Fe–S isotope constraints on the ore-forming sources and mineralization processes of gold and polymetallic deposits in the Liaodong Peninsula, North China Craton","authors":"Lei Xu ,&nbsp;Jin-Hui Yang ,&nbsp;Qing-Dong Zeng ,&nbsp;Hao Wang ,&nbsp;Lie-Wen Xie","doi":"10.1016/j.oregeorev.2024.106274","DOIUrl":"10.1016/j.oregeorev.2024.106274","url":null,"abstract":"<div><div>Plenty of gold and polymetallic deposits are widespread in the eastern part of the North China Craton. They are associated with mafic to felsic dikes and hosted by Precambrian basement or Mesozoic granitoids. However, the sources of gold and other metals in the ore-forming fluids remain controversial. Here we present in-situ S and Fe isotopes and trace element contents of pyrites from various gold and Pb–Zn–(Ag) deposits in the Liaodong Peninsula, China. Pyrites from quartz vein-type gold deposit hosted by Mesozoic granites in the Wulong deposit have relatively homogeneous magmatic-like S isotopes (δ³⁴S values of 0.9 ‰ to 2.5 ‰) and Co/Ni ratios, indicating derivation of sulfur and, by inference, of ore fluids/materials most likely from Mesozoic magmas. In contrast, pyrites from gold and Pb–Zn–(Ag) deposits in the Qingchengzi orefield hosted by Precambrian basement have high and variable δ³⁴S values (9.7 ‰ to 12.7 ‰ for the Wandigou altered rock-type gold deposit and 4.7 ‰ to 8.5 ‰ for the Xiquegou Pb–Zn deposit and the Zhenzigou Pb–Zn–Ag deposit), identical to those of host rocks, indicating the important contributions of gold and other metals from wall rocks to the ore deposits. Pyrites from the various deposits have variable δ⁵⁶Fe values of 0.08 ‰ to 0.63 ‰ for the Pb–Zn–Ag deposit, –0.58 ‰ to 1.23 ‰ for the altered rock-type gold deposit, and –0.68 ‰ to 0.77 ‰ for the quartz vein-type gold deposit, indicating distinct mineralization processes. Rapid precipitation of pyrites (with negative δ⁵⁶Fe values) in the alteration rock and subsequent deposition of pyrites (with positive δ⁵⁶Fe values) from the residual fluids in an Fe-open hydrothermal system during intensive ore-forming fluid-wall rock interaction account for the Pb–Zn–Ag mineralization, while weak fluid-rock interaction and pyrites precipitation from a Fe-closed hydrothermal system contribute to gold mineralization. Our observations provide a robust Fe–S isotope evidence for the contribution of various sources and metallogenic processes for distinct gold and polymetallic deposits.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422243","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 Sr-Nd isotopic implications for the petrogenesis of the late Silurian Shitoukengde mafic–ultramafic intrusion in the East Kunlun Orogen, NW China","authors":"Wen Chen ,&nbsp;Lie-Meng Chen ,&nbsp;Song-Yue Yu ,&nbsp;Da-Peng Li ,&nbsp;Jian Kang ,&nbsp;Hua-Liang Huang ,&nbsp;Shu-Kuan Wu ,&nbsp;Zhi-An Wang","doi":"10.1016/j.oregeorev.2024.106264","DOIUrl":"10.1016/j.oregeorev.2024.106264","url":null,"abstract":"<div><div>The Shitoukengde mafic–ultramafic intrusion is the host of the second-largest sulfide deposit after the Xiarihamu Ni-Co deposit in the East Kunlun Orogenic Belt (EKOB), northern Tibet Plateau, China. Despite several studies, the age, petrogenesis, and the cause of low Ni-tenor for this intrusion remain poorly constrained. In this study, zircons separated from the pyroxenite at Shitoukengde yield a SHRIMP U-Pb age of 418.9 ± 3.1 Ma, corresponding to the widespread magmatism of the late Silurian to early Devonian in the EKOB. Whole-rock major and trace element compositions indicate that fractional crystallization played a key role in controlling the magma composition and element distribution within the intrusion. Mafic-ultramafic rocks of the intrusion, particularly peridotite, have highly variable and exceptionally elevated (⁸⁷Sr/⁸⁶Sr)_i and negative ɛ_Nd(t) values. Some samples from the Shitoukengde intrusion exhibit initial Sr-Nd isotope ratios that overlap with those from the Xiarihamu intrusion, while others (e.g., peridotite) display higher (⁸⁷Sr/⁸⁶Sr)_i values than those observed in the latter. The unusual Sr-Nd isotopic compositions of the Shitoukengde intrusion could be attributed to the assimilation of Mg-rich carbonate within a deep-seated magma chamber. This contamination process facilitates the crystallization of olivine, consequently reducing Ni content in residual magma. Furthermore, the contamination of Mg-rich carbonate may promote oxygen fugacity and thus enhance the solubility of sulfur while restricting the sulfide saturation in the magma. We thus propose that the extensive contamination of Mg-rich carbonate is a key factor contributing to the relatively low Ni-tenor observed at Shitoukengde.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422363","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":"Mineral prospectivity mapping susceptibility evaluation based on interpretable ensemble learning","authors":"Zhengbo Yu ,&nbsp;Binbin Li ,&nbsp;Xingjie Wang","doi":"10.1016/j.oregeorev.2024.106248","DOIUrl":"10.1016/j.oregeorev.2024.106248","url":null,"abstract":"<div><div>In the present study, an interpretable ensemble learning-based method for mineral prediction mapping is proposed to address the limitations of traditional mineralization prediction modeling. A stacking ensemble learning model was constructed, employing random forest (RF), extreme gradient boosting (XGBoost), and AdaBoost as primary learners, and logistic regression as the secondary learner. The model’s interpretability was analyzed using local interpretable model-agnostic explanations (LIME) and shapley additive explanations (SHAP) algorithms. The lead–zinc deposits in the Changba mining area of Gansu Province served as a case study. By integrating geological and geochemical data, and selecting 18 evaluation factors, the effectiveness and interpretability of the ensemble learning model in mineralization prediction were validated. The results demonstrate that the lead–zinc prospecting map generated using the stacking model effectively correlates geological and geochemical data with known lead–zinc deposit locations, significantly enhancing the accuracy of identifying potential lead–zinc prospecting areas.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359149","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":"Genesis studies of Li–Rb deposits in pegmatites from Bailongshan, western China: Evidence from chronology, fluid inclusions, and H–O isotope analysis","authors":"Wei Wang ,&nbsp;Wei Liu ,&nbsp;Xiaofei Du ,&nbsp;Zongquan Yao ,&nbsp;Lingling Gao ,&nbsp;Yong Li ,&nbsp;Chuan Chen ,&nbsp;Huadong Ma ,&nbsp;Zhengle Chen ,&nbsp;Libo Wang","doi":"10.1016/j.oregeorev.2024.106255","DOIUrl":"10.1016/j.oregeorev.2024.106255","url":null,"abstract":"<div><div>The Bailongshan Pegmatite deposit, located in the West Kunlun Orogenic Belt, Northwest China, is a newly discovered, super-large Li–Rb (Be–Ta–Nb) rare-metal deposit. Since complex magmatic-hydrothermal processes are responsible for the mineralization of such rare-element pegmatites, it is desirable to study the evolution and sources of ore-forming fluids to analyze the genesis of ore deposits. In this study, the ⁴⁰Ar/³⁹Ar plateau ages of muscovite and biotite were determined to be 171.36 ± 1.87 and 172.39 ± 1.66 Ma, respectively, indicating that the duration of hydrothermal mineralization was approximately 170 Ma. Based on the zonal nature of the mineral assemblage, the Bailongshan area was divided into four zones and stages (I–IV), namely the albite–quartz–lithium tourmaline (AQT, stage I), albite–quartz-bearing mica (AQM, stage II), albite–quartz–spodumene (AQS, stage Ⅲ), and spodumene–quartz (SQ, stage IV) zones. Among these, AQS and SQ were the main ore-bearing areas. In terms of the fluid inclusions found in quartz and spodumene, the different types include a gas-rich phase (V-type), a liquid-rich phase (L-type), a daughter mineral-bearing three-phase (S-type), and a carbon dioxide-bearing phase (C-type). In stage I, the homogeneous temperatures of the V- and S-type fluid inclusions varied from 365 to 415 °C, while their corresponding salinities were 8.5–12.9 and 44.8–47.2 wt% NaCl equiv., respectively. In stage II, the homogeneous temperature and salinity of the L-type inclusions were 315–365 °C and 9.9–13.3 wt% NaCl equiv., respectively, while in stages Ⅲ and IV, the homogeneous temperatures of the L- and S-type fluid inclusions were between 235 and 335 °C, while their salinities were 7.2–12.3 and 32.1–37.0 wt% NaCl equiv., respectively. Furthermore, for the C-type inclusions, the homogeneous temperature and salinity were 235–320 °C and 4.9–10.6 wt% NaCl equiv., respectively. The laser Raman results showed that the fluid in the metallogenic stage was an H₂O–NaCl–CO₂–CH₄ system. Based on the homogeneous temperature and salinity results, the fluid capture pressure from stage III to stage IV was calculated to be 280–150 MPa, and the depth of the capture was &gt;6 km. Moreover, the H–O isotope results suggested that the early ore-forming fluids are mainly magmatic hydrothermal fluids, whereas the later (stage IV) mineralizing fluids may be mixed with a small amount of meteoric water. The subsequent immiscibility of the fluid may be one of the factors responsible for the discharge and precipitation of minerals.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359147","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}