Pub Date : 2024-10-20DOI: 10.1016/j.oregeorev.2024.106297
Mingqian Wu , Xi Diao , Iain M. Samson , Xu Zheng
What role post-magmatic processes have played in the development and mineralization of rare-metal peraluminous granites and how important that role can be, are questions that researchers have been wrestling with for decades. The Yichun Li-Ta-Nb deposit is an example that has been the subject of such a debate. The granitic appearance of rocks, the inert nature of tantalum, and the scarcity of mineralization in country rocks have been taken to suggest that fluid overprints were limited to within the granites and were unimportant in rock- and ore-forming processes. In this study, the identification of two types of abundant Li- and Cs-rich pseudomorphs in both the topaz-lepidolite granite and overlying pegmatite, the only two mineralized units at Yichun, suggests that extensive metasomatism was involved in rock and ore formation. The textural and chemical similarities of lepidolite in comparable mineral assemblages from a variety of occurrences, including lepidolite in pseudomorphs, veins, and miarolitic cavities from both the topaz-lepidolite granite and pegmatite, suggest that all lepidolite at Yichun is metasomatic and largely inherited its chemical signatures from a magmatic-hydrothermal transitional fluid, rich in Li, Cs, and Ta, derived possibly from the Li-muscovite granite that lies beneath the topaz-lepidolite granite. We propose that this transitional liquid, composition of which lies between a silicate melt and aqueous fluid, was not in equilibrium with the original igneous mineralogy, thus bringing about significant metasomatism along its infiltration and evolution upwards. Variations in the trace-element composition of lepidolite likely reflect the influence on mineral compositions by precursor minerals. The ambiguous boundary between the topaz-lepidolite and Li-muscovite granites, combined with the intensely metasomatized nature of the former, is most consistent with the topaz-lepidolite granite being the extensively altered upper portion of the Li-muscovite granite, which is itself somewhat metasomatized. Although magmatic fractionation played a key role in the initial concentration of Nb, Li, and Ta in both granite and pegmatite formation, the Li-Ta-Nb-Cs mineralization and its host rocks were largely formed through magmatic-hydrothermal rejuvenation and re-enrichment.
后岩浆作用过程在稀有金属过铝花岗岩的发育和成矿过程中发挥了什么作用，以及这种作用的重要性有多大，这些都是研究人员几十年来一直在争论的问题。宜春锂-钽-铌矿床就是这样一个争论不休的例子。岩石的花岗岩外观、钽的惰性以及乡村岩石中矿化物的稀少都被认为表明，流体的叠加作用仅限于花岗岩内部，在岩石和矿石形成过程中并不重要。在本研究中，宜春仅有的两个成矿单元--黄玉-鳞片花岗岩和上覆伟晶岩中均发现了两种类型的富锂离子和铯离子假象体，这表明在岩石和矿石形成过程中存在广泛的变质作用。在各种矿点的可比矿物组合中，鳞片岩的纹理和化学成分都很相似，包括黄玉鳞片岩花岗岩和伟晶岩的假象、矿脉和混合岩洞中的鳞片岩、这表明宜春的所有鳞片岩都是变质岩，其化学特征主要来自岩浆-热液过渡液，富含锂、铯和钽，可能来自黄玉鳞片岩花岗岩下的锂锰花岗岩。我们认为，这种过渡液的成分介于硅酸盐熔体和水液之间，与原始火成岩矿物学不平衡，因此在其渗透和向上演化的过程中产生了显著的变质作用。鳞片岩痕量元素成分的变化很可能反映了前驱矿物对矿物成分的影响。黄玉鳞片花岗岩和锂锰花岗岩之间的边界模糊不清，再加上前者具有强烈的变质作用，这最符合黄玉鳞片花岗岩是锂锰花岗岩上部的广泛蚀变，而锂锰花岗岩本身也具有一定程度的变质作用。虽然在花岗岩和伟晶岩形成过程中，岩浆分馏对 Nb、Li 和 Ta 的初始富集起了关键作用，但锂-Ta-Nb-Cs 矿化及其母岩在很大程度上是通过岩浆-热液再富集和再富集形成的。
{"title":"Role of metasomatism in formation of the Yichun rare-metal deposit, China","authors":"Mingqian Wu , Xi Diao , Iain M. Samson , Xu Zheng","doi":"10.1016/j.oregeorev.2024.106297","DOIUrl":"10.1016/j.oregeorev.2024.106297","url":null,"abstract":"<div><div>What role post-magmatic processes have played in the development and mineralization of rare-metal peraluminous granites and how important that role can be, are questions that researchers have been wrestling with for decades. The Yichun Li-Ta-Nb deposit is an example that has been the subject of such a debate. The granitic appearance of rocks, the inert nature of tantalum, and the scarcity of mineralization in country rocks have been taken to suggest that fluid overprints were limited to within the granites and were unimportant in rock- and ore-forming processes. In this study, the identification of two types of abundant Li- and Cs-rich pseudomorphs in both the topaz-lepidolite granite and overlying pegmatite, the only two mineralized units at Yichun, suggests that extensive metasomatism was involved in rock and ore formation. The textural and chemical similarities of lepidolite in comparable mineral assemblages from a variety of occurrences, including lepidolite in pseudomorphs, veins, and miarolitic cavities from both the topaz-lepidolite granite and pegmatite, suggest that all lepidolite at Yichun is metasomatic and largely inherited its chemical signatures from a magmatic-hydrothermal transitional fluid, rich in Li, Cs, and Ta, derived possibly from the Li-muscovite granite that lies beneath the topaz-lepidolite granite. We propose that this transitional liquid, composition of which lies between a silicate melt and aqueous fluid, was not in equilibrium with the original igneous mineralogy, thus bringing about significant metasomatism along its infiltration and evolution upwards. Variations in the trace-element composition of lepidolite likely reflect the influence on mineral compositions by precursor minerals. The ambiguous boundary between the topaz-lepidolite and Li-muscovite granites, combined with the intensely metasomatized nature of the former, is most consistent with the topaz-lepidolite granite being the extensively altered upper portion of the Li-muscovite granite, which is itself somewhat metasomatized. Although magmatic fractionation played a key role in the initial concentration of Nb, Li, and Ta in both granite and pegmatite formation, the Li-Ta-Nb-Cs mineralization and its host rocks were largely formed through magmatic-hydrothermal rejuvenation and re-enrichment.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106297"},"PeriodicalIF":3.2,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535119","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}
Rapidly growing demand for cobalt and nickel in rechargeable battery industry promotes research on metallogenic theory of magmatic Cu-Ni-Co sulfide deposits. Xiarihamu Cu-Ni-Co deposit, one of the lately discovered Co-rich magmatic sulfide deposits in China, is typical of distribution in orogenic belts, rather than in divergent tectonic settings as many deposits of the same type. In-situ elemental and sulfur isotopic analyses of base metal sulfides (BMS; pyrrhotite, pentlandite, and chalcopyrite) from Xiarihamu were conducted in this study. The strongly negative correlation between Fe and Co + Ni reveals the major occurrence of Co and Ni as isomorphism states in pentlandite and pyrrhotite. The δ34S values of pentlandite and pyrrhotite generally increase with Co contents and Co/Ni ratios, indicating that the Co enrichment within BMS accompanied with enhanced contamination of crustal sulfur. Zinc, Cd, Sb, and Te are significantly and preferentially fractionated into intermediate sulfide solution (ISS) from which chalcopyrite exsolved. The Se contents and Se/S ratios of pentlandite and pyrrhotite in lherzolite/harzburgite are much higher than those of BMS from gabbro, which has systematically higher δ34S values. Combined with the partially overlapped Sb/Se and As/Se ratios of BMS from lherzolite and gabbro, as well as similar calculated R factors of ore-hosting peridotite and gabbro, it is proposed that the studied Xiarihamu gabbro was crystallized from a separate pulse of Co-Ni-enriched, Se-depleted and intensively contaminated mafic parent magma, rather than evolved from ultramafic magma through crystallization fractionation. The lack of olivine and spinel in gabbro also promoted more Co and Ni into sulfide liquid. Based on Se/Te ratios, the pentlandite and pyrrhotite from drill core XH1E01S was originated from sulfide liquid, which suffered higher degree of crystallization fractionation of monosulfide solution (MSS). While pentlandite and pyrrhotite that crystallized from less evolved parent sulfide liquid bear less cobalt, such as those collected from drill core XH1109. This study strengthens the potential importance of crustal contamination and crystallization fractionation of MSS from sulfide liquid during Co enrichment within BMS (pentlandite and pyrrhotite).
充电电池行业对钴和镍的需求快速增长，促进了对岩浆硫化铜镍钴矿床成矿理论的研究。夏日哈木铜镍钴矿床是最近在中国发现的富钴岩浆硫化物矿床之一，它典型地分布在造山带，而不像许多同类型矿床那样分布在分异构造环境中。本研究对夏利哈木的贱金属硫化物（BMS，黄铁矿、辉铜矿和黄铜矿）进行了原位元素和硫同位素分析。铁和 Co + Ni 之间的强烈负相关表明，Co 和 Ni 主要以同构态存在于戊铁矿和黄铁矿中。红柱石和黄铁矿的δ34S值一般随Co含量和Co/Ni比值的增加而增加，表明BMS内Co的富集伴随着地壳硫污染的增强。锌、镉、锑和碲被大量优先分馏到中间硫化物溶液（ISS）中，黄铜矿就是从中间硫化物溶液中溶解出来的。蛭石/哈兹堡垒岩中的辉铜矿和黄铁矿的硒含量和硒/硫比远远高于辉长岩中的BMS，而后者的δ34S值一直较高。结合蛭石和辉长岩中 BMS 的 Sb/Se 和 As/Se 比率部分重叠，以及托矿橄榄岩和辉长岩相似的 R 因子计算值，可以推测所研究的霞里哈木辉长岩是由富含 Co-Ni、Se 贫化和严重污染的黑云母岩浆的独立脉冲结晶而成，而不是由超黑云母岩浆通过结晶分馏演化而来。辉长岩中橄榄石和尖晶石的缺乏也促使更多的钴和镍进入硫化物液体中。根据Se/Te比，钻芯XH1E01S中的戊兰特石和黄铁矿来源于硫化液，而硫化液受到单硫化物溶液（MSS）的结晶分馏程度较高。而从演化程度较低的硫化母液中结晶出来的戊铁矿和黄铁矿所含的钴则较少，如从 XH1109 号钻探岩芯中采集到的戊铁矿和黄铁矿。这项研究加强了地壳污染和结晶分馏硫化物液中的单硫化物溶液在BMS（戊兰铁矿和黄铁矿）内富钴过程中的潜在重要性。
{"title":"The cobalt and nickel enrichment in base metal sulfides from the Xiarihamu Cu-Ni-Co deposit, China: Constrained by in-situ mineral geochemistry of sulfides","authors":"Shang Liu, Ya-Wen Bao, Ming-Jie Zhang, Xue-Jing Gan, Xi-Zheng Gong, Rong-Qiang Kang","doi":"10.1016/j.oregeorev.2024.106300","DOIUrl":"10.1016/j.oregeorev.2024.106300","url":null,"abstract":"<div><div>Rapidly growing demand for cobalt and nickel in rechargeable battery industry promotes research on metallogenic theory of magmatic Cu-Ni-Co sulfide deposits. Xiarihamu Cu-Ni-Co deposit, one of the lately discovered Co-rich magmatic sulfide deposits in China, is typical of distribution in orogenic belts, rather than in divergent tectonic settings as many deposits of the same type. <em>In-situ</em> elemental and sulfur isotopic analyses of base metal sulfides (BMS; pyrrhotite, pentlandite, and chalcopyrite) from Xiarihamu were conducted in this study. The strongly negative correlation between Fe and Co + Ni reveals the major occurrence of Co and Ni as isomorphism states in pentlandite and pyrrhotite. The δ<sup>34</sup>S values of pentlandite and pyrrhotite generally increase with Co contents and Co/Ni ratios, indicating that the Co enrichment within BMS accompanied with enhanced contamination of crustal sulfur. Zinc, Cd, Sb, and Te are significantly and preferentially fractionated into intermediate sulfide solution (ISS) from which chalcopyrite exsolved. The Se contents and Se/S ratios of pentlandite and pyrrhotite in lherzolite/harzburgite are much higher than those of BMS from gabbro, which has systematically higher δ<sup>34</sup>S values. Combined with the partially overlapped Sb/Se and As/Se ratios of BMS from lherzolite and gabbro, as well as similar calculated R factors of ore-hosting peridotite and gabbro, it is proposed that the studied Xiarihamu gabbro was crystallized from a separate pulse of Co-Ni-enriched, Se-depleted and intensively contaminated mafic parent magma, rather than evolved from ultramafic magma through crystallization fractionation. The lack of olivine and spinel in gabbro also promoted more Co and Ni into sulfide liquid. Based on Se/Te ratios, the pentlandite and pyrrhotite from drill core XH1E01S was originated from sulfide liquid, which suffered higher degree of crystallization fractionation of monosulfide solution (MSS). While pentlandite and pyrrhotite that crystallized from less evolved parent sulfide liquid bear less cobalt, such as those collected from drill core XH1109. This study strengthens the potential importance of crustal contamination and crystallization fractionation of MSS from sulfide liquid during Co enrichment within BMS (pentlandite and pyrrhotite).</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106300"},"PeriodicalIF":3.2,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535118","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}
The porphyry Cu-related intrusions commonly comprise multiple phases such as the large Nurkazgan porphyry Cu-Au deposit in Central Kazakhstan, hosted in the Karagandinsky dioritic to granitic intrusive complex. Here, SHRIMP and LA-ICP-MS zircon U-Pb dating on the multiple ore-bearing intrusions from this complex confirms a punctuated magmatic history distributed over 35 m.y., and marked by three episodic porphyry events rather than a single event, with the oldest event being the early granodiorite and quartz diorite porphyries at ca. 437–440 Ma, the second being the quartz diorite porphyry at 429.7 ± 2.1 Ma, and the last being the late granodiorite and quartz diorite porphyries at 402.8 ± 3.7 Ma and 402.0 ± 3.9 Ma, respectively. The mineralization is related to the two younger episodic intrusions of quartz diorite porphyry at ∼ 430 Ma and ∼ 402 Ma, respectively. SIMS U-Pb dating of hydrothermal, Cu-rich (up to 20.9 ppm) rutile from the breccia-type ores directly constrains the timing of porphyry mineralization at 428.9 ± 6.9 Ma, which is coincident with the emplacement age of the ∼ 430 Ma quartz diorite porphyry, and thus demonstrates this porphyry as a causative intrusion generating main-stage mineralization. This close genetic link is also supported by the chondrite-normalized REE patterns of rutile, which show remarkably similar light REE-enrichments and moderate negative Eu anomalies to those of the ∼ 430 Ma quartz diorite porphyry. A molybdenite sample obtained from the main-ore stage vein, however, has a Re-Os age of 418.6 ± 1.8 Ma, which is slightly younger than the U-Pb age determinations of rutile. This indicates that the Re-Os isotope system was disturbed by the second (post-ore) thermal event related to ∼ 402 Ma quartz diorite porphyry. In line with published data, this study suggests that the rutile U-Pb age in combination with its REE patterns can be a powerful tool to trace the causative porphyry. Moreover, the typical LREE-enriched REE patterns coupled with the high Cu anomalies, inherited from the causative porphyry and related exsolving fluids, can be as diagnostic proxies for distinguishing the porphyry Cu-related hydrothermal rutile from those formed in orogenic gold deposits. Based on these two geochemical discriminators and U-Pb ages, rutile can serve as unique fingerprints to help improve porphyry copper exploration in green field or covered terranes to complement detrital zircon fertility indicators.
与斑岩铜有关的侵入体通常由多个阶段组成，如位于哈萨克斯坦中部的大型 Nurkazgan 斑岩铜金矿床，就坐落在卡拉甘金斯基闪长岩至花岗岩侵入体复合体中。在这里，对这一复合体中的多个含矿侵入体进行的 SHRIMP 和 LA-ICP-MS 锆石 U-Pb 测定证实了一个分布于 35 m.y. 的点状岩浆史，其特征是三个偶发斑岩事件而非单一事件，最古老的事件是早期花岗闪长岩和石英闪长岩斑岩，时间约为 437-440 Ma.最古老的事件是约 437-440 Ma 的早期花岗闪长岩和石英闪长岩斑岩，第二个是 429.7 ± 2.1 Ma 的石英闪长岩斑岩，最后一个是分别为 402.8 ± 3.7 Ma 和 402.0 ± 3.9 Ma 的晚期花岗闪长岩和石英闪长岩斑岩。矿化与石英闪长岩斑岩的两个较年轻的偶发侵入体有关，时间分别为 ∼ 430 Ma 和 ∼ 402 Ma。从角砾岩型矿石中提取的热液富铜（高达百万分之 20.9）金红石的 SIMS U-Pb 定年直接确定了斑岩成矿的时间为 428.9 ± 6.9 Ma，这与∼ 430 Ma 的石英闪长岩斑岩的成岩年龄相吻合，从而证明了该斑岩是产生主要阶段成矿作用的成因侵入体。金红石的软玉归一化 REE 模式也证明了这种密切的遗传联系，该模式与 430 Ma∼ 石英闪长岩斑岩的轻度 REE 富集和中度负 Eu 异常极为相似。然而，从主矿阶段矿脉中获得的辉钼矿样品的Re-Os年龄为418.6 ± 1.8 Ma，比金红石的U-Pb年龄测定结果稍早。这表明，Re-Os同位素系统受到了与∼ 402 Ma石英闪长斑岩有关的第二次（矿石后）热事件的干扰。与已发表的数据一致，这项研究表明，金红石的U-Pb年龄与其REE模式相结合，可以成为追踪成因斑岩的有力工具。此外，典型的 LREE 富集 REE 模式与高铜异常（由成因斑岩和相关外溶解流体继承）可作为诊断代用指标，用于区分斑岩铜相关热液金红石与成因金矿床中形成的金红石。根据这两个地球化学判别因素和 U-Pb 年龄，金红石可以作为独特的指纹，帮助改进绿地或覆盖地层中的斑岩铜矿勘探，以补充碎屑锆石肥度指标。
{"title":"Hydrothermal rutile chemistry and U-Pb age fingerprinting of the formation of the giant Nurkazgan porphyry Cu-Au deposit, Central Kazakhstan","authors":"Haoxuan Feng , Reimar Seltmann , Ping Shen , Xiangkai Chu , Qingyu Suo , Eleonora Seitmuratova , Vitaly Shatov","doi":"10.1016/j.oregeorev.2024.106293","DOIUrl":"10.1016/j.oregeorev.2024.106293","url":null,"abstract":"<div><div>The porphyry Cu-related intrusions commonly comprise multiple phases such as the large Nurkazgan porphyry Cu-Au deposit in Central Kazakhstan, hosted in the Karagandinsky dioritic to granitic intrusive complex. Here, SHRIMP and LA-ICP-MS zircon U-Pb dating on the multiple ore-bearing intrusions from this complex confirms a punctuated magmatic history distributed over 35 m.y., and marked by three episodic porphyry events rather than a single event, with the oldest event being the early granodiorite and quartz diorite porphyries at ca. 437–440 Ma, the second being the quartz diorite porphyry at 429.7 ± 2.1 Ma, and the last being the late granodiorite and quartz diorite porphyries at 402.8 ± 3.7 Ma and 402.0 ± 3.9 Ma, respectively. The mineralization is related to the two younger episodic intrusions of quartz diorite porphyry at ∼ 430 Ma and ∼ 402 Ma, respectively. SIMS U-Pb dating of hydrothermal, Cu-rich (up to 20.9 ppm) rutile from the breccia-type ores directly constrains the timing of porphyry mineralization at 428.9 ± 6.9 Ma, which is coincident with the emplacement age of the ∼ 430 Ma quartz diorite porphyry, and thus demonstrates this porphyry as a causative intrusion generating main-stage mineralization. This close genetic link is also supported by the chondrite-normalized REE patterns of rutile, which show remarkably similar light REE-enrichments and moderate negative Eu anomalies to those of the ∼ 430 Ma quartz diorite porphyry. A molybdenite sample obtained from the main-ore stage vein, however, has a Re-Os age of 418.6 ± 1.8 Ma, which is slightly younger than the U-Pb age determinations of rutile. This indicates that the Re-Os isotope system was disturbed by the second (post-ore) thermal event related to ∼ 402 Ma quartz diorite porphyry. In line with published data, this study suggests that the rutile U-Pb age in combination with its REE patterns can be a powerful tool to trace the causative porphyry. Moreover, the typical LREE-enriched REE patterns coupled with the high Cu anomalies, inherited from the causative porphyry and related exsolving fluids, can be as diagnostic proxies for distinguishing the porphyry Cu-related hydrothermal rutile from those formed in orogenic gold deposits. Based on these two geochemical discriminators and U-Pb ages, rutile can serve as unique fingerprints to help improve porphyry copper exploration in green field or covered terranes to complement detrital zircon fertility indicators.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106293"},"PeriodicalIF":3.2,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535124","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}
Pub Date : 2024-10-18DOI: 10.1016/j.oregeorev.2024.106292
Daniel Patias , Renjie Zhou , Xin Wang , Jonathan C. Aitchison
Ophiolites provide important insights for understanding of subduction zones and forearc mantle-wedge geodynamics. Specifically, within the mantle section, podiform chromitites may record processes associated with development of highly depleted supra-subduction ophiolites, chromium mineralization and subsequent metasomatism. This study explores the first ever U-Pb isotope and trace-element data obtained from titanites in chromitites of the Dun Mountain ophiolite belt in New Zealand. Titanite is unusual in such geochemically depleted rocks and a low recovery rate attests to its rarity (ca. 190 grains from 100 kg of material from two chromitite samples). Results of U-Pb geochronology and geochemistry for the titanites constrain both the mid-Permian timing of chromitite crystallization (∼283 Ma) and later metasomatism (∼272 Ma). Older titanite grains are depleted in HFSE and have flat REE chondrite-normalized patterns reflecting a high-degree of partial melting in depths greater than the plagioclase stability field (>15 km). Younger titanites show enrichment in HFSE, depletion in LREE and negative Eu anomalies, revealing melt extraction at shallower depths (<15 km) that likely record refertilization of the mantle-wedge. Results highlight the potential of titanites in the acquisition of direct geochronological and geochemical constraints from rocks commonly devoid of minerals suitable for U-Pb dating.
{"title":"New approach to constraining Cr-mineralization and forearc processes: U-Pb dating and geochemistry of titanites in chromitites of the Dun Mountain ophiolite belt (New Zealand)","authors":"Daniel Patias , Renjie Zhou , Xin Wang , Jonathan C. Aitchison","doi":"10.1016/j.oregeorev.2024.106292","DOIUrl":"10.1016/j.oregeorev.2024.106292","url":null,"abstract":"<div><div>Ophiolites provide important insights for understanding of subduction zones and forearc mantle-wedge geodynamics. Specifically, within the mantle section, podiform chromitites may record processes associated with development of highly depleted supra-subduction ophiolites, chromium mineralization and subsequent metasomatism. This study explores the first ever U-Pb isotope and trace-element data obtained from titanites in chromitites of the Dun Mountain ophiolite belt in New Zealand. Titanite is unusual in such geochemically depleted rocks and a low recovery rate attests to its rarity (ca. 190 grains from 100 kg of material from two chromitite samples). Results of U-Pb geochronology and geochemistry for the titanites constrain both the mid-Permian timing of chromitite crystallization (∼283 Ma) and later metasomatism (∼272 Ma). Older titanite grains are depleted in HFSE and have flat REE chondrite-normalized patterns reflecting a high-degree of partial melting in depths greater than the plagioclase stability field (>15 km). Younger titanites show enrichment in HFSE, depletion in LREE and negative Eu anomalies, revealing melt extraction at shallower depths (<15 km) that likely record refertilization of the mantle-wedge. Results highlight the potential of titanites in the acquisition of direct geochronological and geochemical constraints from rocks commonly devoid of minerals suitable for U-Pb dating.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106292"},"PeriodicalIF":3.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535120","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}
Pub Date : 2024-10-18DOI: 10.1016/j.oregeorev.2024.106291
Haobin Niu , Saijun Sun , Binhui Zhang , Minhua Chen , Bin Zhang , Shenglin Lu , Junjie Zhang , Weidong Sun , Yanan Cong
The Nanyangtian scheelite deposit is located in the Nanwenhe-Song Chay dome (NSCD), southeastern Yunnan. This deposit has undergone four metallogenic stages and is characterized by several kilometers of bedded scheelite-bearing skarn (NYT-II stage), feldspar-bearing quartz veins (NYT-III stage), and sulfides (NYT-IV stage) in the Neoproterozoic schist and gneiss, all of which exhibit similar fold deformations. Throughout the stages, Th and salinity of fluids gradually decrease, weakly and positively correlating, representing a slow cooling process. NYT-I fluids (F-, H2O-rich and high T, p), as indicated by the plagioclase within feldspar-bearing quartz veins, may have directly evolved from a highly fractional residual melt or a salt-rich aqueous melt, signifying the magmatic-hydrothermal transition. From NYT-II to NYT-III fluids, a wider variation of δ18OH2O (−2.4 ∼ 5.1 ‰) to a narrow range of δ18OH2O (2.8 ∼ 5.1 ‰), and a narrow δ34S range (5.18 ‰ ∼ 8.62 ‰) also indicates that fluids may evolve from the relatively oxidized granitic magma. Furthermore, NYT-I fluids could extend throughout the entire fluid evolution, culminating in two diverse paths: one is a much purer magmatic water towards the NYT-III and NYT-IV fluids, and the other is a more meteoric water-dominated towards the NYT-II fluids. A lower water/rock ratio (W/R) existed in the NYT-II stage, leading to the formation of moderately oxidized Tungsten (W)-skarns and scheelites through the NYT-I salt-rich aqueous melts or their reactions with wall rocks in a stable environment. W/R ratios increased in the NYT-III stage, resulting in the formation of NYT-III feldspar-bearing quartz veins with CO2 generation and alkalinity enhancement. As oxidation diminished, fluids gradually evolved into the NYT-IV fluids, forming sulfides.
{"title":"Discrimination of two diverse fluid evolutions from the Nanyangtian scheelite deposit, southeastern Yunnan: Evidences from fluid inclusions and mineral geochemistry","authors":"Haobin Niu , Saijun Sun , Binhui Zhang , Minhua Chen , Bin Zhang , Shenglin Lu , Junjie Zhang , Weidong Sun , Yanan Cong","doi":"10.1016/j.oregeorev.2024.106291","DOIUrl":"10.1016/j.oregeorev.2024.106291","url":null,"abstract":"<div><div>The Nanyangtian scheelite deposit is located in the Nanwenhe-Song Chay dome (NSCD), southeastern Yunnan. This deposit has undergone four metallogenic stages and is characterized by several kilometers of bedded scheelite-bearing skarn (NYT-II stage), feldspar-bearing quartz veins (NYT-III stage), and sulfides (NYT-IV stage) in the Neoproterozoic schist and gneiss, all of which exhibit similar fold deformations. Throughout the stages, T<sub>h</sub> and salinity of fluids gradually decrease, weakly and positively correlating, representing a slow cooling process. NYT-I fluids (F-, H<sub>2</sub>O-rich and high T, <em>p</em>), as indicated by the plagioclase within feldspar-bearing quartz veins, may have directly evolved from a highly fractional residual melt or a salt-rich aqueous melt, signifying the magmatic-hydrothermal transition. From NYT-II to NYT-III fluids, a wider variation of δ<sup>18</sup>O<sub>H2O</sub> (−2.4 ∼ 5.1 ‰) to a narrow range of δ<sup>18</sup>O<sub>H2O</sub> (2.8 ∼ 5.1 ‰), and a narrow δ<sup>34</sup>S range (5.18 ‰ ∼ 8.62 ‰) also indicates that fluids may evolve from the relatively oxidized granitic magma. Furthermore, NYT-I fluids could extend throughout the entire fluid evolution, culminating in two diverse paths: one is a much purer magmatic water towards the NYT-III and NYT-IV fluids, and the other is a more meteoric water-dominated towards the NYT-II fluids. A lower water/rock ratio (W/R) existed in the NYT-II stage, leading to the formation of moderately oxidized Tungsten (W)-skarns and scheelites through the NYT-I salt-rich aqueous melts or their reactions with wall rocks in a stable environment. W/R ratios increased in the NYT-III stage, resulting in the formation of NYT-III feldspar-bearing quartz veins with CO<sub>2</sub> generation and alkalinity enhancement. As oxidation diminished, fluids gradually evolved into the NYT-IV fluids, forming sulfides.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106291"},"PeriodicalIF":3.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535123","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}
Pub Date : 2024-10-16DOI: 10.1016/j.oregeorev.2024.106281
Kunda Badhe , Pei Ni , Guo Guang Wang , Zheng Liu , Wensheng Li , Junying Ding , Junyi Pan
The Jiapigou auriferous belt in Jilin province has been recognized as substantial gold-producers in the North China Craton (NCC). Gold mineralization in this district mainly occurs in mineralized quartz veins and alteration zones, characterized by silicification, pyritization, and argillitization. The quartz veins contain three generations of mineralized quartz, namely, qtz1 (probably oldest), qtz2 (slightly younger), and qtz3 (probably youngest) were identified using SEM-CL. The fluid inclusions in all three generations of quartz are broadly of three types, viz., bi-phase Ia (H2O-CO2), tri-phase Ib (H2O-CO2-NaCl ± CH4), and II (H2O-NaCl).The micro-thermometric analysis of the type Ia and Ib fluid inclusion in qtz1 & qtz2 have aqueous-carbonic composition and exhibit a similar salinity of 1.1 to 7.8 wt% NaCl equivalent, whereas the homogenization temperature (Th) range varies from ∼237 to ∼350 °C. These ore-related fluid inclusions are of low to moderate salinity, and show mixture of CO2 and CH4. On the other hand, Type II fluid inclusions are dominant in qtz3. They have salinity of 3.2 to 12.7 wt% NaCl equivalent and homogenization temperature varying between 180 °C and 210 °C. These data indicate that the ore-forming fluid evolved from a CO2–H2O–NaCl ± CH4 system during the mineralization period.
The X-ray elemental maps of pyrite acquired using electron microprobe analysis (EPMA) show irregular zones of Co and Ni indicating two generations of pyrite. The early-stage pyrite which occupies core portion shows high Co and Ni, whereas the later-stage pyrite occupying rim has lower Co and Ni. The laser ablation-inductively coupled plasma-mass spectrometer (LA-ICPMS) analyses of pyrite has indicated that pyrite-1 is rich in Au + Ag + Se + Cu + Co + Ni, whereas, pyrite-2 has lower concentration of these elements. A positive correlation between Fe and other chalcophile elements reported here (i.e. Au + Ag + Se + Cu + Co + Ni), might be due to fluid-rock interaction resulting into a saturated fluid that subsequently precipitated along the microfractures within earlier-formed pyrite and quartz. The in-situ δ34S values in pyrite from Jiapigou deposits overlap in the range of +4.5 to +9.6 ‰, which is consistent with the ore-forming fluids of the crustal origin input during fluid-rock interaction. The systematic pyrite compositional observations and fluid inclusions study documented here to provide new insight into the process of ore formation for the Au enrichment in the Jiapigou deposit.
吉林省的贾皮沟金矿带被认为是华北克拉通（NCC）的重要产金区。该地区的金矿主要分布在矿化石英脉和蚀变带中，蚀变带的特征是硅化、黄铁矿化和磷酸盐化。石英脉中含有三代矿化石英，即 qtz1（可能是最古老的）、qtz2（稍年轻）和 qtz3（可能是最年轻的）。所有三代石英中的流体包裹体大致分为三种类型，即qtz1 & qtz2 中的 Ia 和 Ib 型流体包裹体的显微测温分析结果显示其成分为水碳酸，盐度为 1.1 至 7.8 wt% NaCl 当量，均化温度（Th）范围为 237 至 350 °C。这些与矿石有关的流体包裹体具有低到中等的盐度，并显示出二氧化碳和甲烷的混合物。另一方面，第二类流体包裹体在qtz3中占主导地位。它们的盐度在 3.2 至 12.7 wt% NaCl 当量之间，均化温度在 180 °C 至 210 °C 之间。利用电子微探针分析（EPMA）获得的黄铁矿 X 射线元素图显示，Co 和 Ni 呈不规则带状，表明黄铁矿有两代。占据核心部分的早期黄铁矿显示出较高的 Co 和 Ni，而占据边缘部分的晚期黄铁矿则显示出较低的 Co 和 Ni。黄铁矿的激光烧蚀-电感耦合等离子体质谱仪（LA-ICPMS）分析表明，黄铁矿-1 富含 Au + Ag + Se + Cu + Co + Ni，而黄铁矿-2 中这些元素的浓度较低。这里报告的铁和其他亲黄元素（即金+银+硒+铜+钴+镍）之间的正相关关系，可能是由于流体-岩石相互作用导致饱和流体，随后沿着早期形成的黄铁矿和石英内部的微裂隙沉淀下来。嘉皮沟矿床黄铁矿的原位δ34S值在+4.5至+9.6‰范围内重叠，这与流岩作用过程中输入的地壳源成矿流体一致。本文通过对黄铁矿成分的系统观察和流体包裹体的研究，对家皮沟矿床金富集的成矿过程有了新的认识。
{"title":"Fluid inclusion and pyrite geochemistry of the Jiapigou gold deposit, North China Craton: Implication for origin of orogenic gold deposit?","authors":"Kunda Badhe , Pei Ni , Guo Guang Wang , Zheng Liu , Wensheng Li , Junying Ding , Junyi Pan","doi":"10.1016/j.oregeorev.2024.106281","DOIUrl":"10.1016/j.oregeorev.2024.106281","url":null,"abstract":"<div><div>The Jiapigou auriferous belt in Jilin province has been recognized as substantial gold-producers in the North China Craton (NCC). Gold mineralization in this district mainly occurs in mineralized quartz veins and alteration zones, characterized by silicification, pyritization, and argillitization. The quartz veins contain three generations of mineralized quartz, namely, qtz1 (probably oldest), qtz2 (slightly younger), and qtz3 (probably youngest) were identified using SEM-CL. The fluid inclusions in all three generations of quartz are broadly of three types, viz., bi-phase Ia (H<sub>2</sub>O-CO<sub>2</sub>), tri-phase Ib (H<sub>2</sub>O-CO<sub>2</sub>-NaCl ± CH<sub>4</sub>), and II (H<sub>2</sub>O-NaCl).The micro-thermometric analysis of the type Ia and Ib fluid inclusion in qtz1 & qtz2 have aqueous-carbonic composition and exhibit a similar salinity of 1.1 to 7.8 wt% NaCl equivalent, whereas the homogenization temperature (Th) range varies from ∼237 to ∼350 °C. These ore-related fluid inclusions are of low to moderate salinity, and show mixture of CO<sub>2</sub> and CH<sub>4</sub>. On the other hand, Type II fluid inclusions are dominant in qtz3. They have salinity of 3.2 to 12.7 wt% NaCl equivalent and homogenization temperature varying between 180 °C and 210 °C. These data indicate that the ore-forming fluid evolved from a CO<sub>2</sub>–H<sub>2</sub>O–NaCl ± CH<sub>4</sub> system during the mineralization period.</div><div>The X-ray elemental maps of pyrite acquired using electron microprobe analysis (EPMA) show irregular zones of Co and Ni indicating two generations of pyrite. The early-stage pyrite which occupies core portion shows high Co and Ni, whereas the later-stage pyrite occupying rim has lower Co and Ni. The laser ablation-inductively coupled plasma-mass spectrometer (LA-ICPMS) analyses of pyrite has indicated that pyrite-1 is rich in Au + Ag + Se + Cu + Co + Ni, whereas, pyrite-2 has lower concentration of these elements. A positive correlation between Fe and other chalcophile elements reported here (i.e. Au + Ag + Se + Cu + Co + Ni), might be due to fluid-rock interaction resulting into a saturated fluid that subsequently precipitated along the microfractures within earlier-formed pyrite and quartz. The in-situ δ<sup>34</sup>S values in pyrite from Jiapigou deposits overlap in the range of +4.5 to +9.6 ‰, which is consistent with the ore-forming fluids of the crustal origin input during fluid-rock interaction. The systematic pyrite compositional observations and fluid inclusions study documented here to provide new insight into the process of ore formation for the Au enrichment in the Jiapigou deposit.</div></div>","PeriodicalId":19644,"journal":{"name":"Ore Geology Reviews","volume":"174 ","pages":"Article 106281"},"PeriodicalIF":3.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534980","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}
Pub Date : 2024-10-15DOI: 10.1016/j.oregeorev.2024.106280
Zhenzhong Xiang , Lin Ye , Chen Wei , Tao Wu , Shiyu Liu , Yusi Hu , Zhilong Huang , Sichen Liu , Minghong Zheng , Lin Du
<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
{"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":"174 ","pages":"Article 106280"},"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}
Pub Date : 2024-10-12DOI: 10.1016/j.oregeorev.2024.106259
Fernando Tornos , Carmen Conde , David Rodriguez , Dolores García , John M. Hanchar , Jesús García Nieto , Gonzalo Ares , Tobias E. Bauer , Luis Rodriguez Pevida
<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
{"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":"174 ","pages":"Article 106259"},"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}
Pub Date : 2024-10-11DOI: 10.1016/j.oregeorev.2024.106282
Liang Liu , Rui-Zhong Hu , Ya-Zhou Fu , Jie-Hua Yang , Mei-Fu Zhou , Wei Mao , Yan-Wen Tang , Alongkot Fanka , Zhen Li
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 εHf(t) 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 εHf(t) 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. < 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 syn-collisional crustal thickening in Paleo-Tethys and post-collisional extension-related settings in Neo-Tethys.
{"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 , Rui-Zhong Hu , Ya-Zhou Fu , Jie-Hua Yang , Mei-Fu Zhou , Wei Mao , Yan-Wen Tang , Alongkot Fanka , 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<sub>Hf</sub>(<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<sub>Hf</sub>(<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. < 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":"174 ","pages":"Article 106282"},"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}
Pub Date : 2024-10-11DOI: 10.1016/j.oregeorev.2024.106283
Xue-li Ma , Kai-tuo Shi , Ke-yong Wang , Chun-kit Lai , Rui Wang
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 (δ18OH2O = − 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.
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.
{"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 , Kai-tuo Shi , Ke-yong Wang , Chun-kit Lai , 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-H<sub>2</sub>O system. The microthermometric and H–O isotope data (δ<sup>18</sup>O<sub>H2O</sub> = − 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 (δ<sup>34</sup>S = − 2.9–3.8 ‰) and Pb (<sup>206</sup>Pb/<sup>204</sup>Pb = 17.954 − 18.492, <sup>207</sup>Pb/<sup>204</sup>Pb = 15.427 − 15.739, <sup>208</sup>Pb/ <sup>204</sup>Pb = 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":"174 ","pages":"Article 106283"},"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}
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