Leeysmon Hulijeli, Yasushi Watanabe, Osamu Nishikawa, Carmela Alen J. Tupaz
Coastal and river sand sequences of Holocene age at Orokolo Bay in Papua New Guinea are host to secondary titanomagnetite ore deposits. The resource developer (Mayur Resources) declares a measured orebody of 139 million tons at grades of 11.35% Fe, 1.94% Ti, and 712 ppm Zr. Orokolo Bay is located near the boundary between the Papuan Thrust and Fold Belt and the Aure Fold Belt. This region is characterized by sedimentary rocks of the Papuan Basin, which are intruded and overlain by a diverse array of magmatic intrusive and volcanic rocks, ranging from mafic alkaline to felsic calc‐alkaline types related to arc–continent collisions in the Cenozoic. The Vailala and Purari rivers located to the east and west of Orokolo Bay, respectively, are the main sediment pathways. Earlier provenance studies have suggested that the deposited sediments mainly come from the erosion of volcanic rocks found within the catchments of these two rivers. However, these studies did not specifically identify the primary source of the Fe‐Ti ores within this region. Here, we report on a potential primary source of the Fe‐Ti ores by examining the occurrence and chemical compositions for detrital titanomagnetites, and associated pyroxene and amphibole minerals. The purpose of this was to discern specific attributes of the primary source for its identification. Lithic sediments comprised of magnesio‐hornblende (Mhbl), tschermakaite (Tsr) and magnesio‐hastingsite (Mhst) amphiboles, clinopyroxene (Cpx), and Fe‐Ti oxide minerals dominate the heavy sands. Feldspar is more abundant than quartz, and Cr‐spinel is rare. Two primary titanomagnetite types were categorized based on their homogeneous grain textures and TiO<jats:sub>2</jats:sub> content, Tmt1 (average 28 wt% TiO<jats:sub>2</jats:sub>) and Tmt2 (average 7 wt% TiO<jats:sub>2</jats:sub>). Pleonaste exsolutions and zircon inclusions distinguish Tmt1 from Tmt2, while apatite and quenched glass inclusions occur in both. A portion of both primary titanomagnetites exhibits hydrothermal overprinting, this subset was categorized as Tmt3 (average 12.5 wt% TiO<jats:sub>2</jats:sub>). Fe‐Ti oxides are associated with Cpx and amphiboles as inclusions, and as pseudomorphs in opacitic amphiboles. Tmt1 coexists predominantly with Mhst‐Tsr but also appears less frequently with Mhbl and Cpx. Tmt2 occurs almost exclusively with Mhbl and Cpx. Titanomagnetite chemistry is low in Cr, Mg, and V content suggesting crystallization from evolved melts. Tmt3 is shows enriched Si, Ca, Al, and Mg concentrations that are characteristic of late‐stage fluids derived from calcareous rocks. Amphibole and Cpx chemistry indicate they were derived from a subalkaline source magma of arc affinity. Fe‐Ti thermobarometry reveals Tmt1 (990 to 967°C, −0.51 to −0.18 ΔNNO) formed at higher temperatures and in less oxidized conditions than Tmt2 (834 to 689°C, 0.33 to 3.2 ΔNNO). Amphibole thermobarometry reveals Mhst‐Tsr and Mhbl formed under similar conditions as Tmt1 and
{"title":"Primary source of titanomagnetite ores at the Orokolo Bay placer deposit: Implications for petrogenesis","authors":"Leeysmon Hulijeli, Yasushi Watanabe, Osamu Nishikawa, Carmela Alen J. Tupaz","doi":"10.1111/rge.12337","DOIUrl":"https://doi.org/10.1111/rge.12337","url":null,"abstract":"Coastal and river sand sequences of Holocene age at Orokolo Bay in Papua New Guinea are host to secondary titanomagnetite ore deposits. The resource developer (Mayur Resources) declares a measured orebody of 139 million tons at grades of 11.35% Fe, 1.94% Ti, and 712 ppm Zr. Orokolo Bay is located near the boundary between the Papuan Thrust and Fold Belt and the Aure Fold Belt. This region is characterized by sedimentary rocks of the Papuan Basin, which are intruded and overlain by a diverse array of magmatic intrusive and volcanic rocks, ranging from mafic alkaline to felsic calc‐alkaline types related to arc–continent collisions in the Cenozoic. The Vailala and Purari rivers located to the east and west of Orokolo Bay, respectively, are the main sediment pathways. Earlier provenance studies have suggested that the deposited sediments mainly come from the erosion of volcanic rocks found within the catchments of these two rivers. However, these studies did not specifically identify the primary source of the Fe‐Ti ores within this region. Here, we report on a potential primary source of the Fe‐Ti ores by examining the occurrence and chemical compositions for detrital titanomagnetites, and associated pyroxene and amphibole minerals. The purpose of this was to discern specific attributes of the primary source for its identification. Lithic sediments comprised of magnesio‐hornblende (Mhbl), tschermakaite (Tsr) and magnesio‐hastingsite (Mhst) amphiboles, clinopyroxene (Cpx), and Fe‐Ti oxide minerals dominate the heavy sands. Feldspar is more abundant than quartz, and Cr‐spinel is rare. Two primary titanomagnetite types were categorized based on their homogeneous grain textures and TiO<jats:sub>2</jats:sub> content, Tmt1 (average 28 wt% TiO<jats:sub>2</jats:sub>) and Tmt2 (average 7 wt% TiO<jats:sub>2</jats:sub>). Pleonaste exsolutions and zircon inclusions distinguish Tmt1 from Tmt2, while apatite and quenched glass inclusions occur in both. A portion of both primary titanomagnetites exhibits hydrothermal overprinting, this subset was categorized as Tmt3 (average 12.5 wt% TiO<jats:sub>2</jats:sub>). Fe‐Ti oxides are associated with Cpx and amphiboles as inclusions, and as pseudomorphs in opacitic amphiboles. Tmt1 coexists predominantly with Mhst‐Tsr but also appears less frequently with Mhbl and Cpx. Tmt2 occurs almost exclusively with Mhbl and Cpx. Titanomagnetite chemistry is low in Cr, Mg, and V content suggesting crystallization from evolved melts. Tmt3 is shows enriched Si, Ca, Al, and Mg concentrations that are characteristic of late‐stage fluids derived from calcareous rocks. Amphibole and Cpx chemistry indicate they were derived from a subalkaline source magma of arc affinity. Fe‐Ti thermobarometry reveals Tmt1 (990 to 967°C, −0.51 to −0.18 ΔNNO) formed at higher temperatures and in less oxidized conditions than Tmt2 (834 to 689°C, 0.33 to 3.2 ΔNNO). Amphibole thermobarometry reveals Mhst‐Tsr and Mhbl formed under similar conditions as Tmt1 and","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223187","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}
The southern Great Xing'an Range (SGXR), an important polymetallic metallogenic province in the eastern Central Asian Orogenic Belt (CAOB) in Northeast China, containing numerous ore deposits of Cu, Fe, Pb, Zn, Au, and so forth. The Changchunling Pb–Zn deposit, located in the eastern segment of the SGXR, is primarily hosted by a Permian conglomerate and siltstone unit. The paragenetic sequence of the deposit can be divided into three stages involving arsenopyrite–quartz (stage I); pyrite–sphalerite–galena–quartz (stage II); and barren quartz–carbonate (stage III). Fluid inclusion (FIs) microthermometric studies revealed that only liquid‐rich aqueous inclusions (VL‐type FIs) are observed in the ore‐bearing quartz veins. The FIs of stages I, II, and III yield homogenization temperatures of 190–314, 170–268, and 140–195°C with salinities of 9.73–13.44, 7.86–10.74, and 4.94–5.99 wt% NaCl eqv., respectively. The ore‐forming fluids are characterized by low temperature and low salinity of the H2O–NaCl fluid system. The δ18OH2O and δD values range from −11.8‰ to 0‰ and −120.4‰ to −99.9‰, respectively, indicating that the source of the fluids was primarily derived from a mixed fluid of magmatic water and meteoric water. Fluid cooling, mixing and fluid‐rock reactions were the major ore precipitation mechanisms at Chanchunling. Sulfur‐lead isotopes of pyrite and sphalerite (δ34S = 2.3‰–3.7‰, 206Pb/204Pb = 18.259–18.285, 207Pb/204Pb = 15.544–15.57, and 208Pb/204Pb = 38.136–38.215) indicate that ore metals had a magmatic source. Integrating the available geological, mineralization, fluid inclusion, and H–O–S–Pb isotope evidence, we conclude that the Changchunling Pb–Zn deposit is an epithermal system, which shares many similar features with the regional Pb–Zn polymetallic deposit.
{"title":"Fluid evolution and genesis of the Changchunling Pb–Zn deposit in the Southern Great Xing'an Range, Northeast China: Constraints from fluid inclusions and H–O–S–Pb isotopes","authors":"Xue‐li Ma, Kai‐tuo Shi, Kai‐rui Song, Rui Wang","doi":"10.1111/rge.12335","DOIUrl":"https://doi.org/10.1111/rge.12335","url":null,"abstract":"The southern Great Xing'an Range (SGXR), an important polymetallic metallogenic province in the eastern Central Asian Orogenic Belt (CAOB) in Northeast China, containing numerous ore deposits of Cu, Fe, Pb, Zn, Au, and so forth. The Changchunling Pb–Zn deposit, located in the eastern segment of the SGXR, is primarily hosted by a Permian conglomerate and siltstone unit. The paragenetic sequence of the deposit can be divided into three stages involving arsenopyrite–quartz (stage I); pyrite–sphalerite–galena–quartz (stage II); and barren quartz–carbonate (stage III). Fluid inclusion (FIs) microthermometric studies revealed that only liquid‐rich aqueous inclusions (VL‐type FIs) are observed in the ore‐bearing quartz veins. The FIs of stages I, II, and III yield homogenization temperatures of 190–314, 170–268, and 140–195°C with salinities of 9.73–13.44, 7.86–10.74, and 4.94–5.99 wt% NaCl eqv., respectively. The ore‐forming fluids are characterized by low temperature and low salinity of the H<jats:sub>2</jats:sub>O–NaCl fluid system. The δ<jats:sup>18</jats:sup>O<jats:sub>H2O</jats:sub> and δD values range from −11.8‰ to 0‰ and −120.4‰ to −99.9‰, respectively, indicating that the source of the fluids was primarily derived from a mixed fluid of magmatic water and meteoric water. Fluid cooling, mixing and fluid‐rock reactions were the major ore precipitation mechanisms at Chanchunling. Sulfur‐lead isotopes of pyrite and sphalerite (δ<jats:sup>34</jats:sup>S = 2.3‰–3.7‰, <jats:sup>206</jats:sup>Pb/<jats:sup>204</jats:sup>Pb = 18.259–18.285, <jats:sup>207</jats:sup>Pb/<jats:sup>204</jats:sup>Pb = 15.544–15.57, and <jats:sup>208</jats:sup>Pb/<jats:sup>204</jats:sup>Pb = 38.136–38.215) indicate that ore metals had a magmatic source. Integrating the available geological, mineralization, fluid inclusion, and H–O–S–Pb isotope evidence, we conclude that the Changchunling Pb–Zn deposit is an epithermal system, which shares many similar features with the regional Pb–Zn polymetallic deposit.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141502554","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}
Yousif Mohammad, Dnya Latif, Mohammad Pirouei, Danar Omer
The study probes the mineralogical and geochemical features of manganese‐iron deposits located in the Sirna area, which is a part of the late Cretaceous Walash Group in the Zagros suture zone, situated in the Kurdistan region of northeastern Iraq. Our investigation comprised field surveys, examination of ore petrography, besides using x‐ray diffraction, SEM‐EDS analysis, x‐ray fluorescence analyses, and inductively coupled plasma mass spectrometry techniques conducted on a set of representative samples. A significant Mn‐Fe ovoidal ore body, extending across 25 meters in diameter, protrudes between the lower strata of soft gray shale and the upper strata of massive limestone within the Walash group. The deposit exhibits a distinct separation into three layers: a lower horizon characterized by abundance of oxide of silicon, an upper horizon enriched in manganese oxide, and a transition layer dominated by hematite (Fe2O3). From a geochemical perspective, there is a gradual decrease in Fe2O3 and SiO2 from the lower to the upper part of the deposit, while MnO, BaO, and SO3 demonstrate a gradual increase. The co‐association of Mn‐Fe‐mineralization in a small restricted tabular ore body suggests that they are genetically related. Within the Sirna manganese‐iron deposit, the prevalent manganese and iron mineral phases are braunite, hollandite, and hematite. Concurrently, the gangue minerals in this deposit encompass cryptocrystalline spheroidal quartz, barite, calcite, and apatite. The Sirna Mn‐Fe deposit exhibits geochemical characteristics such as elevated levels of MnO (reaching up to 68 wt.%) and significant Fe2O3 content (up to 45 wt.%) in the upper manganese and transitional iron horizons, respectively. The Co/Zn ratio (0.28), Ce/La ratio (1.78), low levels of transitional elements (Co + Ni + Cu <0.01 wt.%), and varying concentrations of Ba (up to 6.9 wt.%) suggest that the Siran Mn‐Fe deposit is likely originated from a manganese‐iron silica gel plume that separated from hydrothermal fluids linked to serpentinization. This process is thought to have occurred in the mantle wedge along subduction zone, typically within an arc tectonic environment. Moreover, the presence of remnants of micro‐organisms such as EPS layers, different types of filaments, which are densely covered by biominerals, are important evidence of microbial effect in the mineralization of Mn‐Fe in the study area.
{"title":"Mineralogical and geochemical features of the Sirna Mn‐Fe deposit in the Kurdistan region, northeastern Iraq: Unveiling the formation of a Mn‐Fe silica gel plume via serpentinization hydrothermal mechanisms","authors":"Yousif Mohammad, Dnya Latif, Mohammad Pirouei, Danar Omer","doi":"10.1111/rge.12336","DOIUrl":"https://doi.org/10.1111/rge.12336","url":null,"abstract":"The study probes the mineralogical and geochemical features of manganese‐iron deposits located in the Sirna area, which is a part of the late Cretaceous Walash Group in the Zagros suture zone, situated in the Kurdistan region of northeastern Iraq. Our investigation comprised field surveys, examination of ore petrography, besides using x‐ray diffraction, SEM‐EDS analysis, x‐ray fluorescence analyses, and inductively coupled plasma mass spectrometry techniques conducted on a set of representative samples. A significant Mn‐Fe ovoidal ore body, extending across 25 meters in diameter, protrudes between the lower strata of soft gray shale and the upper strata of massive limestone within the Walash group. The deposit exhibits a distinct separation into three layers: a lower horizon characterized by abundance of oxide of silicon, an upper horizon enriched in manganese oxide, and a transition layer dominated by hematite (Fe<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>). From a geochemical perspective, there is a gradual decrease in Fe<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> and SiO<jats:sub>2</jats:sub> from the lower to the upper part of the deposit, while MnO, BaO, and SO<jats:sub>3</jats:sub> demonstrate a gradual increase. The co‐association of Mn‐Fe‐mineralization in a small restricted tabular ore body suggests that they are genetically related. Within the Sirna manganese‐iron deposit, the prevalent manganese and iron mineral phases are braunite, hollandite, and hematite. Concurrently, the gangue minerals in this deposit encompass cryptocrystalline spheroidal quartz, barite, calcite, and apatite. The Sirna Mn‐Fe deposit exhibits geochemical characteristics such as elevated levels of MnO (reaching up to 68 wt.%) and significant Fe<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> content (up to 45 wt.%) in the upper manganese and transitional iron horizons, respectively. The Co/Zn ratio (0.28), Ce/La ratio (1.78), low levels of transitional elements (Co + Ni + Cu <0.01 wt.%), and varying concentrations of Ba (up to 6.9 wt.%) suggest that the Siran Mn‐Fe deposit is likely originated from a manganese‐iron silica gel plume that separated from hydrothermal fluids linked to serpentinization. This process is thought to have occurred in the mantle wedge along subduction zone, typically within an arc tectonic environment. Moreover, the presence of remnants of micro‐organisms such as EPS layers, different types of filaments, which are densely covered by biominerals, are important evidence of microbial effect in the mineralization of Mn‐Fe in the study area.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141502695","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}
ZhuoMing Li, QingYan Tang, Hong Song, Yan Zhang, Wei Liu, TianBao Su, Chi Zhao, JiChang Zhao
Graphite is a strategic mineral resource of the world. The Dashuixiabei (DSXB) crystalline graphite deposit is located in the Dongbatu area in the Altyn crystalline graphite metallogenic belt. This study presents data from x‐ray diffraction (XRD), scanning electron microscopy (SEM), laser Raman spectroscopy, and fluid inclusions analysis conducted on the DSXB crystalline graphite deposit. The graphite is flake shaped, with a diameter of 0.1–0.4 mm. A group of extremely complete cleavage was observed under SEM, and the overall distribution was a flake. The C content in graphite is greater than 90 wt%, followed by N, O, and so on. The results of XRD analysis show that the lattice parameters of the DSXB crystalline graphite is a = 0.246–0.2465 nm, c = 0.6714–0.6715 nm, and V = 0.03519–0.03532 nm3. The degree of graphitization ranges from 0.8490 to 0.8519, indicating that the graphite crystal structure is relatively intact, the average metamorphic temperature is 552°C, and the content of 3R polytypes ranges from 13.16% to 13.25%. It is concluded that the metamorphic rocks of the DSXB crystalline graphite deposit have undergone medium‐grade metamorphism. The Raman spectral peaks show that DSXB crystalline graphite has a high degree of crystallinity. The DSXB crystalline graphite ore is dominated by hydrothermal fluids with medium‐low temperature and medium‐low salinity, and the vapor phase of the fluid inclusions is composed of CH4. There may be a superposition of the main and secondary mineralization stages. The crystalline graphite from the DSXB deposit shows high quality and stable ore quality, which has good metallogenic conditions and development and utilization prospects.
{"title":"Mineralogical characteristics and fluid inclusions of the Dashuixiabei crystalline graphite deposit in the Dunhuang block","authors":"ZhuoMing Li, QingYan Tang, Hong Song, Yan Zhang, Wei Liu, TianBao Su, Chi Zhao, JiChang Zhao","doi":"10.1111/rge.12334","DOIUrl":"https://doi.org/10.1111/rge.12334","url":null,"abstract":"Graphite is a strategic mineral resource of the world. The Dashuixiabei (DSXB) crystalline graphite deposit is located in the Dongbatu area in the Altyn crystalline graphite metallogenic belt. This study presents data from x‐ray diffraction (XRD), scanning electron microscopy (SEM), laser Raman spectroscopy, and fluid inclusions analysis conducted on the DSXB crystalline graphite deposit. The graphite is flake shaped, with a diameter of 0.1–0.4 mm. A group of extremely complete cleavage was observed under SEM, and the overall distribution was a flake. The C content in graphite is greater than 90 wt%, followed by N, O, and so on. The results of XRD analysis show that the lattice parameters of the DSXB crystalline graphite is <jats:italic>a</jats:italic> = 0.246–0.2465 nm, <jats:italic>c</jats:italic> = 0.6714–0.6715 nm, and <jats:italic>V</jats:italic> = 0.03519–0.03532 nm<jats:sup>3</jats:sup>. The degree of graphitization ranges from 0.8490 to 0.8519, indicating that the graphite crystal structure is relatively intact, the average metamorphic temperature is 552°C, and the content of 3R polytypes ranges from 13.16% to 13.25%. It is concluded that the metamorphic rocks of the DSXB crystalline graphite deposit have undergone medium‐grade metamorphism. The Raman spectral peaks show that DSXB crystalline graphite has a high degree of crystallinity. The DSXB crystalline graphite ore is dominated by hydrothermal fluids with medium‐low temperature and medium‐low salinity, and the vapor phase of the fluid inclusions is composed of CH<jats:sub>4</jats:sub>. There may be a superposition of the main and secondary mineralization stages. The crystalline graphite from the DSXB deposit shows high quality and stable ore quality, which has good metallogenic conditions and development and utilization prospects.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141502555","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}
The Yanghuidongzi Cu deposit is a newly discovered porphyry Cu deposit in the eastern segment of the Central Asian Orogenic Belt. The Cu mineralization is associated with granodiorite porphyry and granodiorite. This paper presents new zircon U–Pb dating, Hf–O isotopes, whole‐rock major and trace elements data for this deposit, to constrain the ore‐forming age and the magma source of the granitoids. LA–ICP–MS U–Pb dating of zircons from granodiorite porphyry and granodiorite samples yielded ages of 192.8 ± 1.7 Ma, and 198.1 ± 1.4 Ma, respectively, which are interpreted as the emplacement ages of granitoids. These age data confirm that the granodiorite porphyry is associated with the porphyry Cu deposit, and both granitic intrusion and Cu mineralization were associated with the Early Jurassic magmatism in NE China. The granodiorite porphyry has high SiO2, Al2O3, and Sr contents together with low concentrations of Y and Yb. It is enriched in LILE, and depleted in HFSE, classified as adakitic. The granodiorite has high SiO2 and K2O, enriched in LILE, depleted in HFSE, and is classified as high‐K calk‐alkaline I‐type granite. The granodiorite porphyry and granodiorite have variable εHf(t) values (5.2 to 9.5), Mesoproterozoic two‐stage Hf models (TDM2) of 629–905 Ma, and δ18O values (4.26‰ to 7.50‰). These geochemical data and zircon Hf–O isotopes suggest that the granodiorite porphyry originated from the partial melting of thickened juvenile crustal materials and granodiorite derived from the partial melting of juvenile crustal materials with an additional of mantle‐derived magmas input. Combining our new data with the regional tectonic setting, the Yanghuidongzi Cu deposit and the related granitoids formed in a compressional tectonic setting associated with the subduction of the Paleo–Pacific Plate beneath the Eurasian continent.
羊蹄洞子铜矿床是中亚造山带东段新发现的斑岩型铜矿床。铜矿化与花岗闪长岩斑岩和花岗闪长岩有关。本文介绍了该矿床新的锆石 U-Pb 测定、Hf-O 同位素、全岩主要元素和微量元素数据，以确定成矿年龄和花岗岩的岩浆来源。花岗闪长岩斑岩和花岗闪长岩样品中的锆石的 LA-ICP-MS U-Pb 测定年龄分别为 192.8 ± 1.7 Ma 和 198.1 ± 1.4 Ma，可解释为花岗岩的成矿年龄。这些年龄数据证实花岗闪长斑岩与斑岩型铜矿床有关，花岗岩侵入体和铜矿化均与中国东北早侏罗世岩浆活动有关。花岗闪长岩斑岩中 SiO2、Al2O3 和 Sr 含量较高，Y 和 Yb 含量较低。它富含 LILE，贫含 HFSE，被归类为赤铁矿。花岗闪长岩具有较高的 SiO2 和 K2O 含量，富含 LILE，贫含 HFSE，属于高 K 碱性 I 型花岗岩。花岗斑岩和花岗闪长岩的εHf(t)值（5.2-9.5）不等，中新生代两阶段Hf模型（TDM2）为629-905 Ma，δ18O值（4.26‰-7.50‰）不等。这些地球化学数据和锆石Hf-O同位素表明，花岗闪长斑岩起源于加厚的幼壳物质的部分熔融，而花岗闪长岩则起源于幼壳物质的部分熔融，并有额外的地幔岩浆输入。结合我们的新数据和区域构造环境，杨水洞子铜矿床和相关花岗岩形成于与古太平洋板块俯冲到欧亚大陆之下相关的压缩构造环境中。
{"title":"Geochronology and geochemistry of granitoids of the Yanghuidongzi porphyry Cu deposit, Heilongjiang Province: Implications for petrogenesis and metallogenic setting during the Early Jurassic in the Northeast of China","authors":"Guoqiang Chen, Peng Zhang, Yan Chang","doi":"10.1111/rge.12332","DOIUrl":"https://doi.org/10.1111/rge.12332","url":null,"abstract":"The Yanghuidongzi Cu deposit is a newly discovered porphyry Cu deposit in the eastern segment of the Central Asian Orogenic Belt. The Cu mineralization is associated with granodiorite porphyry and granodiorite. This paper presents new zircon U–Pb dating, Hf–O isotopes, whole‐rock major and trace elements data for this deposit, to constrain the ore‐forming age and the magma source of the granitoids. LA–ICP–MS U–Pb dating of zircons from granodiorite porphyry and granodiorite samples yielded ages of 192.8 ± 1.7 Ma, and 198.1 ± 1.4 Ma, respectively, which are interpreted as the emplacement ages of granitoids. These age data confirm that the granodiorite porphyry is associated with the porphyry Cu deposit, and both granitic intrusion and Cu mineralization were associated with the Early Jurassic magmatism in NE China. The granodiorite porphyry has high SiO<jats:sub>2</jats:sub>, Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>, and Sr contents together with low concentrations of Y and Yb. It is enriched in LILE, and depleted in HFSE, classified as adakitic. The granodiorite has high SiO<jats:sub>2</jats:sub> and K<jats:sub>2</jats:sub>O, enriched in LILE, depleted in HFSE, and is classified as high‐K calk‐alkaline I‐type granite. The granodiorite porphyry and granodiorite have variable εHf(t) values (5.2 to 9.5), Mesoproterozoic two‐stage Hf models (T<jats:sub>DM2</jats:sub>) of 629–905 Ma, and δ<jats:sup>18</jats:sup>O values (4.26‰ to 7.50‰). These geochemical data and zircon Hf–O isotopes suggest that the granodiorite porphyry originated from the partial melting of thickened juvenile crustal materials and granodiorite derived from the partial melting of juvenile crustal materials with an additional of mantle‐derived magmas input. Combining our new data with the regional tectonic setting, the Yanghuidongzi Cu deposit and the related granitoids formed in a compressional tectonic setting associated with the subduction of the Paleo–Pacific Plate beneath the Eurasian continent.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572862","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}
Otgon‐Erdene Davaasuren, Sang‐Mo Koh, Bum Han Lee, Chul‐Ho Heo
Small‐ to medium‐sized serpentinized ultramafic blocks have been found in several locations in South Korea. Ultramafic‐hosted serpentinization, described as a major hydrothermal process that affects the lithospheric mantle, is known to play a key role in mass fluxes enhanced by multiple fluid–rock interactions that ultimately lead to the formation of hydrothermal mineralization and natural hydrogen production. In this study, we attempted to interpret the hydrothermal alteration and associated Ni‐Cr mineralization of the Andong serpentinized ultramafic block (ASUB). Based on the mineralogical and geochemical studies, the serpentinites and serpentinized ultramafic rocks of the ASUB are interpreted to be derived from mantle peridotite. It shows the dunite, lherzolite, and wehrlite compositions which are mainly composed of olivine and pyroxene. Hydrothermal alteration transformed the ultramafic rock into serpentinitic rock, resulting in changes in rock textures from the parent rock (plutonic texture) to moderately altered rock (pseudomorphic porphyritic texture) and strongly altered rock (pseudomorphic fine grained texture) with mineralogical changes. Serpentinization and Ni‐Cr mineralization do not show any relationship. Considering the reported crystallization age of the parental rock (222 Ma) and measured age (214–187 Ma) of the granites intruded into the ASUB, the source magma responsible for the final hydrothermal event including serpentinization is inferred to be the Late Triassic to Early Jurassic granitic pluton. The ASUB might have formed due to the ascent of a mantle plume along the extensional regime (i.e., rift) in the supra‐subduction zone (SSZ), rather than in ophiolite‐related mid‐oceanic ridges or abyssal environments, which are identified in many places. Ni‐Cr mineralization, with the close association of pentlandite, pyrrhotite, and Cr‐spinel, likely resulted from co‐precipitation and dissemination during the crystallization of the parent peridotitic magma derived from the mantle.
{"title":"Serpentinization and potential Ni‐Cr mineralization of the Andong ultramafic block in South Korea","authors":"Otgon‐Erdene Davaasuren, Sang‐Mo Koh, Bum Han Lee, Chul‐Ho Heo","doi":"10.1111/rge.12331","DOIUrl":"https://doi.org/10.1111/rge.12331","url":null,"abstract":"Small‐ to medium‐sized serpentinized ultramafic blocks have been found in several locations in South Korea. Ultramafic‐hosted serpentinization, described as a major hydrothermal process that affects the lithospheric mantle, is known to play a key role in mass fluxes enhanced by multiple fluid–rock interactions that ultimately lead to the formation of hydrothermal mineralization and natural hydrogen production. In this study, we attempted to interpret the hydrothermal alteration and associated Ni‐Cr mineralization of the Andong serpentinized ultramafic block (ASUB). Based on the mineralogical and geochemical studies, the serpentinites and serpentinized ultramafic rocks of the ASUB are interpreted to be derived from mantle peridotite. It shows the dunite, lherzolite, and wehrlite compositions which are mainly composed of olivine and pyroxene. Hydrothermal alteration transformed the ultramafic rock into serpentinitic rock, resulting in changes in rock textures from the parent rock (plutonic texture) to moderately altered rock (pseudomorphic porphyritic texture) and strongly altered rock (pseudomorphic fine grained texture) with mineralogical changes. Serpentinization and Ni‐Cr mineralization do not show any relationship. Considering the reported crystallization age of the parental rock (222 Ma) and measured age (214–187 Ma) of the granites intruded into the ASUB, the source magma responsible for the final hydrothermal event including serpentinization is inferred to be the Late Triassic to Early Jurassic granitic pluton. The ASUB might have formed due to the ascent of a mantle plume along the extensional regime (i.e., rift) in the supra‐subduction zone (SSZ), rather than in ophiolite‐related mid‐oceanic ridges or abyssal environments, which are identified in many places. Ni‐Cr mineralization, with the close association of pentlandite, pyrrhotite, and Cr‐spinel, likely resulted from co‐precipitation and dissemination during the crystallization of the parent peridotitic magma derived from the mantle.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572970","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}
In high sulfidation systems, acidic hydrothermal fluids can produce wide alteration zones with specific mineral assemblages/associations as well as identifiable and elemental distribution patterns. The Lepanto Cu‐Au deposit exhibits a consistent zonation pattern of silicic alteration near the Cu‐Au veins evolving outwards to advanced argillic and argillic alteration with chloritic alteration farthest from the vein. Recent exploration of high sulfidation Cu‐Au veins indicated the usefulness of mineralogical assemblages/associations and the complementing information provided by the elemental distribution patterns in the identification and characterization of the different alteration zones. In this study, I characterize the mineral assemblages/associations and interpret their occurrences in the different alteration zones of the Lepanto Cu‐Au deposit. An assemblage that is composed predominantly of chlorite‐epidote/clinozoisite‐calcite‐quartz‐pyrite represents the propylitic/chloritic alteration zone. The argillic alteration has a mineral association of smectite‐sericite‐chlorite‐epidote‐kaolinite‐quartz‐pyrite. The advanced argillic alteration zone has alunite‐kaolinite‐pyrophyllite‐diaspore‐sericite‐quartz‐pyrite as mineral association. In the silicic alteration zone, the mineral association is composed of quartz‐alunite‐diaspore‐anhydrite‐pyrite. Also presented are the distributions of trace and rare earth elements. In the distribution of trace and REEs across alteration zones, there is an observed increase of Te, Au, Mo, Cu, Sn, and Bi values from the chloritic to silicic alteration zones. A corresponding decrease of REE, LILE (Ba, Pb, Rb, K), HFSE (Ti, Nb, U, Th), Al, Na, Ca, Zn, Mn, Co and Cd values are observed. This study also characterizes the ore mineral assemblages/associations of the Cu‐Au veins as well as the distribution patterns of trace and rare earth elements. The Northwest‐NOA, hanging wall branch veins (HWBV), main ore body (MOB), foot wall branch veins (FWBV), and Easterlies are generally made up of enargite‐luzonite‐pyrite‐chalcopyrite‐tennantite‐tetrahedrite‐tellurides‐covellite. The associated gangue minerals are anhydrite‐gypsum‐alunite‐barite‐quartz. In the distribution of elements across the different Cu‐Au veins, there is an observed decrease of Cu, As, and Sb values from the Easterlies towards the Northwest‐NOA Cu‐Au veins. The observed variations in the alteration and ore mineral assemblages/associations have strongly influenced the distribution of elemental values in both alteration zones and Cu‐Au veins. The identification of mineralogical assemblages/associations and elemental distribution patterns may provide possible guides and reference tools in the exploration of Lepanto type Cu‐Au deposits.
在高硫化系统中，酸性热液会产生广泛的蚀变带，这些蚀变带具有特定的矿物组合/关联以及可识别的元素分布模式。莱潘托铜金矿床呈现出一致的分带模式，即铜金矿脉附近的硅质蚀变向外演化为晚期的闪长岩和闪长岩蚀变，离矿脉最远的地方则为绿泥石蚀变。最近对高硫化铜金矿脉的勘探表明，矿物组合/关联以及元素分布模式提供的补充信息在识别和描述不同蚀变带方面非常有用。在本研究中，我描述了矿物组合/组合的特征，并解释了它们在莱潘托铜金矿床不同蚀变带中的出现情况。主要由绿泥石-橄榄石/黝帘石-方解石-石英-黄铁矿组成的集合体代表了丙绿泥石/绿泥石蚀变带。辉绿岩蚀变带的矿物组合为绢云母-绿泥石-橄榄石-方解石-石英黄铁矿。晚期箭石蚀变带的矿物组合为白云石-高岭石-褐铁矿-透镜石-绢云母-石英-黄铁矿。在硅质蚀变带，矿物组合为石英-绿泥石-透镜石-无水黄铁矿。此外，还介绍了微量元素和稀土元素的分布情况。在微量元素和稀土元素在各蚀变带的分布中，可以观察到从绿泥石蚀变带到硅质蚀变带，Te、Au、Mo、Cu、Sn 和 Bi 的值都有所增加。观察到 REE、LILE（钡、铅、铷、钾）、HFSE（钛、铌、铀、钍）、Al、Na、Ca、Zn、Mn、Co 和 Cd 值相应减少。这项研究还描述了铜金矿脉的矿石矿物组合/组合特征，以及微量元素和稀土元素的分布模式。西北-NOA、悬壁分支矿脉（HWBV）、主矿体（MOB）、脚壁分支矿脉（FWBV）和复活节矿脉一般由恩长石-吕宋岩-黄铁矿-黄铜矿-天王岩-四面体矿-碲矿-黝帘石组成。伴生的煤矸石矿物为无水石膏-天青石-方解石-石英。在不同铜金矿脉的元素分布中，可以观察到铜、砷和锑的值从东向西向西北-北向铜金矿脉下降。所观察到的蚀变和矿石矿物组合/关联的变化对蚀变带和铜金矿脉的元素值分布产生了很大影响。矿物组合/组合和元素分布模式的确定可为莱潘托型铜金矿床的勘探提供可能的指导和参考工具。
{"title":"Mineralogical attributes to the distribution of trace and rare earth elements in alteration zones and copper‐gold veins in the Lepanto copper‐gold deposit, Luzon, Philippines","authors":"Rene Juna R. Claveria","doi":"10.1111/rge.12330","DOIUrl":"https://doi.org/10.1111/rge.12330","url":null,"abstract":"In high sulfidation systems, acidic hydrothermal fluids can produce wide alteration zones with specific mineral assemblages/associations as well as identifiable and elemental distribution patterns. The Lepanto Cu‐Au deposit exhibits a consistent zonation pattern of silicic alteration near the Cu‐Au veins evolving outwards to advanced argillic and argillic alteration with chloritic alteration farthest from the vein. Recent exploration of high sulfidation Cu‐Au veins indicated the usefulness of mineralogical assemblages/associations and the complementing information provided by the elemental distribution patterns in the identification and characterization of the different alteration zones. In this study, I characterize the mineral assemblages/associations and interpret their occurrences in the different alteration zones of the Lepanto Cu‐Au deposit. An assemblage that is composed predominantly of chlorite‐epidote/clinozoisite‐calcite‐quartz‐pyrite represents the propylitic/chloritic alteration zone. The argillic alteration has a mineral association of smectite‐sericite‐chlorite‐epidote‐kaolinite‐quartz‐pyrite. The advanced argillic alteration zone has alunite‐kaolinite‐pyrophyllite‐diaspore‐sericite‐quartz‐pyrite as mineral association. In the silicic alteration zone, the mineral association is composed of quartz‐alunite‐diaspore‐anhydrite‐pyrite. Also presented are the distributions of trace and rare earth elements. In the distribution of trace and REEs across alteration zones, there is an observed increase of Te, Au, Mo, Cu, Sn, and Bi values from the chloritic to silicic alteration zones. A corresponding decrease of REE, LILE (Ba, Pb, Rb, K), HFSE (Ti, Nb, U, Th), Al, Na, Ca, Zn, Mn, Co and Cd values are observed. This study also characterizes the ore mineral assemblages/associations of the Cu‐Au veins as well as the distribution patterns of trace and rare earth elements. The Northwest‐NOA, hanging wall branch veins (HWBV), main ore body (MOB), foot wall branch veins (FWBV), and Easterlies are generally made up of enargite‐luzonite‐pyrite‐chalcopyrite‐tennantite‐tetrahedrite‐tellurides‐covellite. The associated gangue minerals are anhydrite‐gypsum‐alunite‐barite‐quartz. In the distribution of elements across the different Cu‐Au veins, there is an observed decrease of Cu, As, and Sb values from the Easterlies towards the Northwest‐NOA Cu‐Au veins. The observed variations in the alteration and ore mineral assemblages/associations have strongly influenced the distribution of elemental values in both alteration zones and Cu‐Au veins. The identification of mineralogical assemblages/associations and elemental distribution patterns may provide possible guides and reference tools in the exploration of Lepanto type Cu‐Au deposits.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573075","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}
Jing Ma, Jun You, Tao Hong, Jun Gao, Chu Wu, Xing‐Wang Xu, Qi Wu
The Xilekuduke porphyry Mo‐Cu deposit is located in the Altay‐East Junggar region of the Central Asian Orogenic Belt, northwest China. The orebodies occurring as vein type are host within the monzogranite and granite porphyry. Ore minerals include mainly molybdenite, pyrite, and chalcopyrite, whilst the major alteration include potassic, sericite, carbonate, and silicic. Mineralization can be divided into three stages: quartz‐K‐feldspar–polymetallic stage (Stage I), quartz‐polymetallic stage (Stage II), and quartz–calcite–pyrite (minor) stage (Stage III). Three types of fluid inclusion are present in the Mo‐Cu sulfide–calcite–quartz veins: CO2‐bearing (C‐type), aqueous (W‐type), and daughter mineral‐bearing (S‐type). Petrographic and microthermometric analyses of the fluid inclusions yielded homogenization temperatures for Stage I, II, and III to be 402–499°C, 214–391°C, and 136–254°C, respectively, with corresponding salinities of 39.2–59.6, 3.7–44.9 and 4.1–14.4 wt% NaCl equivalent. The δ18OH₂O and δD values of fluid inclusions in quartz are determined to be 5.3–6.0 ‰ and −76 to −60 ‰ (Stage I), 1.7–3.2 ‰ and −96 to −90 ‰ (Stage II), and −2.6 to −2.4 ‰ and −106 ‰ (Stage III), respectively. These results indicate that the primary ore‐forming fluids (stages I and II) were derived from granitic magma and were mixed with meteoric water in stage III. For the sulfide and sulfate (anhydrite), their δ34S values are of 0.4–5.8 ‰, 13.9–14.4 ‰, respectively, also that suggest a magmatic source. Fluid immiscibility, meteoric water interaction, and ore fluid‐wallrock interactions may have been critical for molybdenum precipitation.
{"title":"The formation mechanism of the Xilekuduke porphyry Mo‐Cu deposit, NW China, revealed by the fluid inclusions and H‐O‐S isotopes","authors":"Jing Ma, Jun You, Tao Hong, Jun Gao, Chu Wu, Xing‐Wang Xu, Qi Wu","doi":"10.1111/rge.12329","DOIUrl":"https://doi.org/10.1111/rge.12329","url":null,"abstract":"The Xilekuduke porphyry Mo‐Cu deposit is located in the Altay‐East Junggar region of the Central Asian Orogenic Belt, northwest China. The orebodies occurring as vein type are host within the monzogranite and granite porphyry. Ore minerals include mainly molybdenite, pyrite, and chalcopyrite, whilst the major alteration include potassic, sericite, carbonate, and silicic. Mineralization can be divided into three stages: quartz‐K‐feldspar–polymetallic stage (Stage I), quartz‐polymetallic stage (Stage II), and quartz–calcite–pyrite (minor) stage (Stage III). Three types of fluid inclusion are present in the Mo‐Cu sulfide–calcite–quartz veins: CO<jats:sub>2</jats:sub>‐bearing (C‐type), aqueous (W‐type), and daughter mineral‐bearing (S‐type). Petrographic and microthermometric analyses of the fluid inclusions yielded homogenization temperatures for Stage I, II, and III to be 402–499°C, 214–391°C, and 136–254°C, respectively, with corresponding salinities of 39.2–59.6, 3.7–44.9 and 4.1–14.4 wt% NaCl equivalent. The δ<jats:sup>18</jats:sup>O<jats:sub>H₂O</jats:sub> and δD values of fluid inclusions in quartz are determined to be 5.3–6.0 ‰ and −76 to −60 ‰ (Stage I), 1.7–3.2 ‰ and −96 to −90 ‰ (Stage II), and −2.6 to −2.4 ‰ and −106 ‰ (Stage III), respectively. These results indicate that the primary ore‐forming fluids (stages I and II) were derived from granitic magma and were mixed with meteoric water in stage III. For the sulfide and sulfate (anhydrite), their δ<jats:sup>34</jats:sup>S values are of 0.4–5.8 ‰, 13.9–14.4 ‰, respectively, also that suggest a magmatic source. Fluid immiscibility, meteoric water interaction, and ore fluid‐wallrock interactions may have been critical for molybdenum precipitation.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140069982","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}
Potential progenitors for W (±Sn) deposits include peraluminous granites of S-type affinity. The anatectic origin of such granites parental to W mineralization has received little attention. This study focuses on Balda Granite (BG), a peraluminous intrusion parental to W-rich ore bodies in the Sirohi region (NW India). We reflect upon the potential source for BG and investigate its anatectic origin through open-system phase equilibria modeling. On the prograde path, muscovite- and biotite-dehydration reactions at 675–745°C and 755–870°C yield ~10 and 13 wt.% melt, respectively. Si, K, Al, and Fe contents of the cumulative melt increased with progressive anatexis. Modeling results suggest high-T (>800°C) stability of the peritectic garnet, which is abundantly observed in the leucosome-dominated migmatitic patches. Cumulative melt extracted till 868°C was chosen to model the crystal fractionation along three polybaric gradients of 30, 45, and 60°C/kbar. As the modeled anatectic melt cooled, its peraluminosity and maficity decreased progressively. With the intermediate cooling gradient of 45°C/kbar, the melt achieved complete crystallization at ~7 km, the depth at which the BG had been emplaced and evolved into a W-rich residual (fractionated) model melt. In terms of peraluminosity, and major and trace element (Lu, Sc, Dy, Y, Yb) chemistry, the fractionated (residual) model melt compares well with BG. This study also models the W concentration in the anatectic melt during its generation and fractional crystallization. We argue for the origin of BG through high-T anatexis of Sirohi Group metapelites and cooling (and fractional crystallization) of the parent anatectic melt at the maximum gradient of 45°C/kbar. Thus, a high-T anatectic origin of granites parental to W deposits may be more prevalent than so far inferred.
W（±Sn）矿床的潜在原生体包括S型亲缘的过铝花岗岩。这类花岗岩是 W 矿化的母岩，但其寒武纪成因却很少受到关注。本研究的重点是 Balda 花岗岩（BG），它是印度西北部 Sirohi 地区富 W 矿体的亲铝侵入体。我们对 BG 的潜在来源进行了思考，并通过开放系统相平衡建模研究了它的无生界起源。在顺行路径上，675-745°C 和 755-870°C 温度下的黝帘石和生物岩脱水反应分别产生了 ~10 和 13 wt.% 的熔体。累积熔体中的硅、钾、铝和铁含量随着渐进式安山期而增加。建模结果表明，包晶石榴石具有高T（800°C）稳定性，这在以白云母为主的偏闪长岩斑块中大量存在。选择提取至 868°C 的累积熔体来模拟沿 30、45 和 60°C/kbar 三个多巴梯度的晶体分馏。随着建模的安山岩熔体冷却，其过铝度和黑云母度逐渐降低。在45°C/千巴的中间冷却梯度下，熔体在大约7千米处完全结晶，即BG的出露深度，并演化成富含W的残余（分馏）模型熔体。在过白度、主要元素和微量元素（Lu、Sc、Dy、Y、Yb）化学性质方面，分馏（残余）模型熔体与 BG 比较接近。这项研究还模拟了无极熔体在生成和分馏结晶过程中的 W 浓度。我们认为，BG 的起源是通过 Sirohi 组偏长岩的高 T 安山岩化和母体安山岩熔体在 45°C/kbar 的最大梯度下的冷却（和分馏结晶）。因此，W矿床母体花岗岩的高T安山岩起源可能比迄今推断的更为普遍。
{"title":"Insights into the anatectic origin of granites parental to tungsten mineralization: A case study from the trans-Aravalli terrane, NW India","authors":"Jitendra Kumar Roy, Aditya Naik, Sourabh Bhattacharya","doi":"10.1111/rge.12327","DOIUrl":"https://doi.org/10.1111/rge.12327","url":null,"abstract":"Potential progenitors for W (±Sn) deposits include peraluminous granites of S-type affinity. The anatectic origin of such granites parental to W mineralization has received little attention. This study focuses on Balda Granite (BG), a peraluminous intrusion parental to W-rich ore bodies in the Sirohi region (NW India). We reflect upon the potential source for BG and investigate its anatectic origin through open-system phase equilibria modeling. On the prograde path, muscovite- and biotite-dehydration reactions at 675–745°C and 755–870°C yield ~10 and 13 wt.% melt, respectively. Si, K, Al, and Fe contents of the cumulative melt increased with progressive anatexis. Modeling results suggest high-T (>800°C) stability of the peritectic garnet, which is abundantly observed in the leucosome-dominated migmatitic patches. Cumulative melt extracted till 868°C was chosen to model the crystal fractionation along three polybaric gradients of 30, 45, and 60°C/kbar. As the modeled anatectic melt cooled, its peraluminosity and maficity decreased progressively. With the intermediate cooling gradient of 45°C/kbar, the melt achieved complete crystallization at ~7 km, the depth at which the BG had been emplaced and evolved into a W-rich residual (fractionated) model melt. In terms of peraluminosity, and major and trace element (Lu, Sc, Dy, Y, Yb) chemistry, the fractionated (residual) model melt compares well with BG. This study also models the W concentration in the anatectic melt during its generation and fractional crystallization. We argue for the origin of BG through high-T anatexis of Sirohi Group metapelites and cooling (and fractional crystallization) of the parent anatectic melt at the maximum gradient of 45°C/kbar. Thus, a high-T anatectic origin of granites parental to W deposits may be more prevalent than so far inferred.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139752117","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}
María Florencia Márquez-Zavalía, Anna Vymazalová, Miguel Ángel Galliski, František Laufek, Marek Tuhý, Yasushi Watanabe, Heinz-Jürgen Bernhardt
The Restauradora vein, is one of the 20 veins of Capillitas (27°27′ S, 66°30′ W), an epithermal precious- and base-metal vein deposit belonging to the Farallón Negro Mining District, northwestern Argentina. One of the main minerals of the paragenesis of Restauradora vein is sphalerite, showing a large substitution of Zn by In and Cu with small participation of Cd and Fe; the fluctuating Zn composition ranges from 0.99 to 0.49 apfu, while In and Cu ranges (apfu) are: 0.22–0.27 and 0.21–0.25, respectively. Under the polarizing-light microscope, using reflected light, the optical properties are those of sphalerite, but with decreasing contents of Zn, especially when Zn is ≤0.60 apfu, a new variety differentiates from regular sphalerite and develops ribbons with paler colors, higher reflectance, softer relative hardness and no internal reflections. The main reflectance values of this In-Cu-rich sphalerite are (Rair, λ/nm): 20.55, 470; 19.43, 546; 19.02, 589; and 18.42, 650. The strongest five x-ray powder-diffraction lines of the synthetic analogue [d in Å (I) (hkl)] are: 3.173 (100) (111); 1.943 (54) (202); 1.657 (37) (113); 1.122 (22) (224); 1.261 (19) (133), the space group is F-43m, with a = 5.49692(10) Å, V = 166,100(10) Å3, Z = 4. Electron-microprobe analyses of the In-Cu-rich sphalerite grains (n = 10) give an average composition (wt%) of: S 29.51, Zn 31.03, In 24.89, Cu 13.49, Ga 0.96, Cd 0.54, Fe 0.05; the average (n = 7) chemical composition of the synthetic phase is: S 29.67, Zn 30.32, In 25.94, Cu 13.82. Despite of the differences, and given that Zn is the main cation and that the structure is the same as that of sphalerite, the mineral studied here is considered as the richest In-Cu variety of sphalerite in the world.
{"title":"Indium-copper-rich sphalerite from the Restauradora vein, Capillitas, Catamarca, Argentina","authors":"María Florencia Márquez-Zavalía, Anna Vymazalová, Miguel Ángel Galliski, František Laufek, Marek Tuhý, Yasushi Watanabe, Heinz-Jürgen Bernhardt","doi":"10.1111/rge.12325","DOIUrl":"https://doi.org/10.1111/rge.12325","url":null,"abstract":"The Restauradora vein, is one of the 20 veins of Capillitas (27°27′ S, 66°30′ W), an epithermal precious- and base-metal vein deposit belonging to the Farallón Negro Mining District, northwestern Argentina. One of the main minerals of the paragenesis of Restauradora vein is sphalerite, showing a large substitution of Zn by In and Cu with small participation of Cd and Fe; the fluctuating Zn composition ranges from 0.99 to 0.49 <i>apfu</i>, while In and Cu ranges (<i>apfu</i>) are: 0.22–0.27 and 0.21–0.25, respectively. Under the polarizing-light microscope, using reflected light, the optical properties are those of sphalerite, but with decreasing contents of Zn, especially when Zn is ≤0.60 <i>apfu</i>, a new variety differentiates from regular sphalerite and develops ribbons with paler colors, higher reflectance, softer relative hardness and no internal reflections. The main reflectance values of this In-Cu-rich sphalerite are (Rair, λ/nm): 20.55, 470; 19.43, 546; 19.02, 589; and 18.42, 650. The strongest five x-ray powder-diffraction lines of the synthetic analogue [<i>d</i> in Å (<i>I</i>) (<i>hkl</i>)] are: 3.173 (100) (111); 1.943 (54) (202); 1.657 (37) (113); 1.122 (22) (224); 1.261 (19) (133), the space group is <i>F</i>-43<i>m</i>, with <i>a</i> = 5.49692(10) Å, <i>V</i> = 166,100(10) Å<sup>3</sup>, <i>Z</i> = 4. Electron-microprobe analyses of the In-Cu-rich sphalerite grains (<i>n</i> = 10) give an average composition (wt%) of: S 29.51, Zn 31.03, In 24.89, Cu 13.49, Ga 0.96, Cd 0.54, Fe 0.05; the average (<i>n</i> = 7) chemical composition of the synthetic phase is: S 29.67, Zn 30.32, In 25.94, Cu 13.82. Despite of the differences, and given that Zn is the main cation and that the structure is the same as that of sphalerite, the mineral studied here is considered as the richest In-Cu variety of sphalerite in the world.","PeriodicalId":21089,"journal":{"name":"Resource Geology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139495944","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}
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