{"title":"上地壳岩浆过程对赛因达克斑岩铜矿床形成的制约:矿物地球化学的启示","authors":"","doi":"10.1016/j.lithos.2024.107829","DOIUrl":null,"url":null,"abstract":"<div><div>Upper crustal magmatic processes play a crucial role in linking the magmatic and hydrothermal systems of porphyry deposits, ultimately controlling the generation of ore-forming fluids. Understanding these processes within a magma chamber is essential for deciphering the formation of porphyry deposits. The Saindak deposit, a large porphyry Cu system in the western Chagai belt, features coeval ore-forming and barren magma pulses, providing key insights into the characterization of porphyry systems. In this study, detailed petrographic observations and geochemical analyses of amphibole, plagioclase, and apatite were conducted to unravel the magmatic evolution at Saindak. Based on textural relationships and crystallization sequences, three distinct populations of amphibole in the ore-forming magma were identified. These amphiboles record the entire fractional crystallization process of magma that initially emplaced at a depth of ∼5 km to the connected magma system at ∼2 km. The study of amphibole and apatite reveals that the fertile magma underwent large-scale fluid exsolution in an open system. The simultaneous and rapid depletion of Cu, Cl, S, and H<sub>2</sub>O in the magma indicates that Cl and S were highly partitioned into the exsolved fluid phase. These elements formed complexes, which effectively concentrated metals in the fluid. Conversely, the barren magma was characterized by either low metal content or limited fluid exsolution within the magma chamber. Overall, we reconstruct the upper crustal magmatic processes at Saindak and conclude that efficient extraction of Cu through fluid exsolution is the key to porphyry deposit formation.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Constraints of upper crust magmatic processes on the formation of Saindak porphyry Cu deposit: Insights from mineral geochemistry\",\"authors\":\"\",\"doi\":\"10.1016/j.lithos.2024.107829\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Upper crustal magmatic processes play a crucial role in linking the magmatic and hydrothermal systems of porphyry deposits, ultimately controlling the generation of ore-forming fluids. Understanding these processes within a magma chamber is essential for deciphering the formation of porphyry deposits. The Saindak deposit, a large porphyry Cu system in the western Chagai belt, features coeval ore-forming and barren magma pulses, providing key insights into the characterization of porphyry systems. In this study, detailed petrographic observations and geochemical analyses of amphibole, plagioclase, and apatite were conducted to unravel the magmatic evolution at Saindak. Based on textural relationships and crystallization sequences, three distinct populations of amphibole in the ore-forming magma were identified. These amphiboles record the entire fractional crystallization process of magma that initially emplaced at a depth of ∼5 km to the connected magma system at ∼2 km. The study of amphibole and apatite reveals that the fertile magma underwent large-scale fluid exsolution in an open system. The simultaneous and rapid depletion of Cu, Cl, S, and H<sub>2</sub>O in the magma indicates that Cl and S were highly partitioned into the exsolved fluid phase. These elements formed complexes, which effectively concentrated metals in the fluid. Conversely, the barren magma was characterized by either low metal content or limited fluid exsolution within the magma chamber. Overall, we reconstruct the upper crustal magmatic processes at Saindak and conclude that efficient extraction of Cu through fluid exsolution is the key to porphyry deposit formation.</div></div>\",\"PeriodicalId\":18070,\"journal\":{\"name\":\"Lithos\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2024-10-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Lithos\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0024493724003438\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Lithos","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0024493724003438","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Constraints of upper crust magmatic processes on the formation of Saindak porphyry Cu deposit: Insights from mineral geochemistry
Upper crustal magmatic processes play a crucial role in linking the magmatic and hydrothermal systems of porphyry deposits, ultimately controlling the generation of ore-forming fluids. Understanding these processes within a magma chamber is essential for deciphering the formation of porphyry deposits. The Saindak deposit, a large porphyry Cu system in the western Chagai belt, features coeval ore-forming and barren magma pulses, providing key insights into the characterization of porphyry systems. In this study, detailed petrographic observations and geochemical analyses of amphibole, plagioclase, and apatite were conducted to unravel the magmatic evolution at Saindak. Based on textural relationships and crystallization sequences, three distinct populations of amphibole in the ore-forming magma were identified. These amphiboles record the entire fractional crystallization process of magma that initially emplaced at a depth of ∼5 km to the connected magma system at ∼2 km. The study of amphibole and apatite reveals that the fertile magma underwent large-scale fluid exsolution in an open system. The simultaneous and rapid depletion of Cu, Cl, S, and H2O in the magma indicates that Cl and S were highly partitioned into the exsolved fluid phase. These elements formed complexes, which effectively concentrated metals in the fluid. Conversely, the barren magma was characterized by either low metal content or limited fluid exsolution within the magma chamber. Overall, we reconstruct the upper crustal magmatic processes at Saindak and conclude that efficient extraction of Cu through fluid exsolution is the key to porphyry deposit formation.
期刊介绍:
Lithos publishes original research papers on the petrology, geochemistry and petrogenesis of igneous and metamorphic rocks. Papers on mineralogy/mineral physics related to petrology and petrogenetic problems are also welcomed.