{"title":"白钨矿作为矽卡岩成矿多阶段成矿过程的微观纹理和地球化学示踪剂:华南新田岭W巨型矿床案例研究","authors":"","doi":"10.1016/j.gr.2024.08.010","DOIUrl":null,"url":null,"abstract":"<div><p>The Xintianling deposit is one of the largest skarn-type scheelite deposit in China. Recent discoveries of quartz-vein-type scheelite mineralization within the deposit have raised questions about its origin and the evolution of ore-forming fluids, hindering a comprehensive understanding of the ore-forming process. We investigate the microtextures, trace elements, and oxygen isotope compositions of scheelite from different stages in both skarn-type and quartz-vein-type W mineralizations. Combined with apatite geochemistry and U–Pb dating, we determine the timing of quartz-vein-type mineralization and the evolution of magmatic-hydrothermal system. Based on detailed petrological observation, three types (seven subtypes) of scheelite and two types of apatite are identified. The Mo contents and Eu/Eu* ratios of scheelite, along with the Ce/Ce* ratios of apatite indicate the oxygen fugacity of fluids during the skarn metallogenic episode is generally higher than that during the quartz-vein metallogenic episode. Furthermore, the Y/Ho ratios and REE patterns of scheelite indicate the presence of at least three significant stages of fluid influx and fluid-rock interactions throughout entire ore-forming process. The O isotope compositions of scheelite in the quartz-vein-type metallogenic episode reveal that the ore-forming fluids are originated from a magmatic source, and meteoric water was mixed into the system, leading to the precipitation of the latest stage of scheelite. The apatites closely coexist with scheelite, from the early and the late stages of quartz-vein metallogenic episode, yield consistent U–Pb ages within error of 160.4 ± 2.4 Ma and 158.4 ± 1.3 Ma, respectively, indicating a close genetic link between quartz-vein-type W mineralization and the fine-grained porphyritic biotite granite. Our study highlights the significance of pulsed fluid exsolution and the combined effects of multiple mechanisms, including fluid-rock interaction, fluid mixing, and physicochemical condition changes, in the formation of large W deposits.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":null,"pages":null},"PeriodicalIF":7.2000,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Scheelite as a microtextural and geochemical tracer of multistage ore-forming processes in skarn mineralization: A case study from the giant Xintianling W deposit, South China\",\"authors\":\"\",\"doi\":\"10.1016/j.gr.2024.08.010\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The Xintianling deposit is one of the largest skarn-type scheelite deposit in China. Recent discoveries of quartz-vein-type scheelite mineralization within the deposit have raised questions about its origin and the evolution of ore-forming fluids, hindering a comprehensive understanding of the ore-forming process. We investigate the microtextures, trace elements, and oxygen isotope compositions of scheelite from different stages in both skarn-type and quartz-vein-type W mineralizations. Combined with apatite geochemistry and U–Pb dating, we determine the timing of quartz-vein-type mineralization and the evolution of magmatic-hydrothermal system. Based on detailed petrological observation, three types (seven subtypes) of scheelite and two types of apatite are identified. The Mo contents and Eu/Eu* ratios of scheelite, along with the Ce/Ce* ratios of apatite indicate the oxygen fugacity of fluids during the skarn metallogenic episode is generally higher than that during the quartz-vein metallogenic episode. Furthermore, the Y/Ho ratios and REE patterns of scheelite indicate the presence of at least three significant stages of fluid influx and fluid-rock interactions throughout entire ore-forming process. The O isotope compositions of scheelite in the quartz-vein-type metallogenic episode reveal that the ore-forming fluids are originated from a magmatic source, and meteoric water was mixed into the system, leading to the precipitation of the latest stage of scheelite. The apatites closely coexist with scheelite, from the early and the late stages of quartz-vein metallogenic episode, yield consistent U–Pb ages within error of 160.4 ± 2.4 Ma and 158.4 ± 1.3 Ma, respectively, indicating a close genetic link between quartz-vein-type W mineralization and the fine-grained porphyritic biotite granite. Our study highlights the significance of pulsed fluid exsolution and the combined effects of multiple mechanisms, including fluid-rock interaction, fluid mixing, and physicochemical condition changes, in the formation of large W deposits.</p></div>\",\"PeriodicalId\":12761,\"journal\":{\"name\":\"Gondwana Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":7.2000,\"publicationDate\":\"2024-08-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Gondwana Research\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1342937X24002521\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gondwana Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1342937X24002521","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
新田岭矿床是中国最大的矽卡岩型白钨矿床之一。最近在该矿床中发现的石英脉型白钨矿化现象引发了人们对其成矿起源和成矿流体演化的疑问,阻碍了对成矿过程的全面了解。我们研究了矽卡岩型和石英脉型白钨矿化不同阶段的白钨矿的微量成分、微量元素和氧同位素组成。结合磷灰石地球化学和U-Pb年代测定,我们确定了石英脉型成矿的时间和岩浆-热液系统的演化过程。根据详细的岩石学观察,确定了三种类型(七个亚型)的白钨矿和两种类型的磷灰石。白钨矿的 Mo 含量和 Eu/Eu* 比值以及磷灰石的 Ce/Ce* 比值表明,矽卡岩成矿期流体的氧富集度普遍高于石英脉成矿期。此外,白钨矿的Y/Ho比率和REE模式表明,在整个成矿过程中至少存在三个重要的流体流入和流体与岩石相互作用阶段。石英脉型成矿事件中白钨矿的O同位素组成显示,成矿流体来源于岩浆源,陨石水混入系统,导致了白钨矿最新阶段的沉淀。在石英脉成矿早期和晚期,与白钨矿紧密共生的磷灰石的U-Pb年龄一致,误差分别为160.4±2.4Ma和158.4±1.3Ma,表明石英脉型W矿化与细粒斑状生物花岗岩之间存在密切的遗传联系。我们的研究强调了脉冲流体外溶解的重要性,以及流体与岩石相互作用、流体混合和物理化学条件变化等多种机制在形成大型W矿床过程中的综合作用。
Scheelite as a microtextural and geochemical tracer of multistage ore-forming processes in skarn mineralization: A case study from the giant Xintianling W deposit, South China
The Xintianling deposit is one of the largest skarn-type scheelite deposit in China. Recent discoveries of quartz-vein-type scheelite mineralization within the deposit have raised questions about its origin and the evolution of ore-forming fluids, hindering a comprehensive understanding of the ore-forming process. We investigate the microtextures, trace elements, and oxygen isotope compositions of scheelite from different stages in both skarn-type and quartz-vein-type W mineralizations. Combined with apatite geochemistry and U–Pb dating, we determine the timing of quartz-vein-type mineralization and the evolution of magmatic-hydrothermal system. Based on detailed petrological observation, three types (seven subtypes) of scheelite and two types of apatite are identified. The Mo contents and Eu/Eu* ratios of scheelite, along with the Ce/Ce* ratios of apatite indicate the oxygen fugacity of fluids during the skarn metallogenic episode is generally higher than that during the quartz-vein metallogenic episode. Furthermore, the Y/Ho ratios and REE patterns of scheelite indicate the presence of at least three significant stages of fluid influx and fluid-rock interactions throughout entire ore-forming process. The O isotope compositions of scheelite in the quartz-vein-type metallogenic episode reveal that the ore-forming fluids are originated from a magmatic source, and meteoric water was mixed into the system, leading to the precipitation of the latest stage of scheelite. The apatites closely coexist with scheelite, from the early and the late stages of quartz-vein metallogenic episode, yield consistent U–Pb ages within error of 160.4 ± 2.4 Ma and 158.4 ± 1.3 Ma, respectively, indicating a close genetic link between quartz-vein-type W mineralization and the fine-grained porphyritic biotite granite. Our study highlights the significance of pulsed fluid exsolution and the combined effects of multiple mechanisms, including fluid-rock interaction, fluid mixing, and physicochemical condition changes, in the formation of large W deposits.
期刊介绍:
Gondwana Research (GR) is an International Journal aimed to promote high quality research publications on all topics related to solid Earth, particularly with reference to the origin and evolution of continents, continental assemblies and their resources. GR is an "all earth science" journal with no restrictions on geological time, terrane or theme and covers a wide spectrum of topics in geosciences such as geology, geomorphology, palaeontology, structure, petrology, geochemistry, stable isotopes, geochronology, economic geology, exploration geology, engineering geology, geophysics, and environmental geology among other themes, and provides an appropriate forum to integrate studies from different disciplines and different terrains. In addition to regular articles and thematic issues, the journal invites high profile state-of-the-art reviews on thrust area topics for its column, ''GR FOCUS''. Focus articles include short biographies and photographs of the authors. Short articles (within ten printed pages) for rapid publication reporting important discoveries or innovative models of global interest will be considered under the category ''GR LETTERS''.