Long Zhang, Xianzhi Pei, Yongbao Gao, Zuochen Li, Ming Liu, Yongkang Jing, Yuanwei Wang, Kang Chen, Nan Deng, Yi Zhang, Junwei Wu
{"title":"中国北柴达木盆地交乐寺 NYF伟晶岩的地球化学、矿物学和地质年代学","authors":"Long Zhang, Xianzhi Pei, Yongbao Gao, Zuochen Li, Ming Liu, Yongkang Jing, Yuanwei Wang, Kang Chen, Nan Deng, Yi Zhang, Junwei Wu","doi":"10.3390/min14080805","DOIUrl":null,"url":null,"abstract":"A significant amount of pegmatite has been discovered on the northwest margin of the Qaidam basin. Among this, the Jiaolesayi pegmatite, located in the northwestern margin of the Quanji Massif (Oulongbuluke micro-continent), shows rare element mineralization potential. Detailed field investigations, along with mineralogical, geochemical, and zircon U-Pb geochronological studies, were carried out on the pegmatite. The results show that the Jiaolesayi pegmatite is syenite, without obvious compositional zoning in the outcrop. It exhibits a peraluminous, high-K calc-alkaline nature with strong depletions in Eu, Sr, Ba, Ti, and P, and high contents of Nb, Ta, Y, Ti, U, Th, and heavy rare earth elements (HREEs), which are primarily concentrated in allanite-(Ce), euxenite-(Y), limonite, thorite, and zircon. The geochemical and mineralogical features of the syenite pegmatite indicate it belongs to the euxenite-type in the rare element class (REE) of the NYF family, with the characteristic accessory mineral being euxenite-(Y). Its 10,000 Ga/Al ratios (2.46 to 2.96), Zr + Nb + Ce + Y contents (998 to 6202 ppm), Y/Nb ratios (0.62 to 0.75), and Yb/Ta ratios (0.80 to 1.49) show an affinity with A1-type granite. Zircons from the syenite sample yielded a weighted mean 206Pb/238U age of 413.6 ± 1.4 Ma, while the elevated U and Th concentrations in the zircons and Th/U ratios (0.04 to 0.16) suggest the possible influence of hydrothermal processes in the late-stage fractional crystallization. In the context of the regional tectonic evolution, the syenite pegmatite may have formed from a basic alkaline magma derived from an OIB-like melt with minor crustal contamination, under the post-collisional extension setting.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.2000,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Geochemistry, Mineralogy, and Geochronology of the NYF Pegmatites, Jiaolesayi, Northern Qaidam Basin, China\",\"authors\":\"Long Zhang, Xianzhi Pei, Yongbao Gao, Zuochen Li, Ming Liu, Yongkang Jing, Yuanwei Wang, Kang Chen, Nan Deng, Yi Zhang, Junwei Wu\",\"doi\":\"10.3390/min14080805\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"A significant amount of pegmatite has been discovered on the northwest margin of the Qaidam basin. Among this, the Jiaolesayi pegmatite, located in the northwestern margin of the Quanji Massif (Oulongbuluke micro-continent), shows rare element mineralization potential. Detailed field investigations, along with mineralogical, geochemical, and zircon U-Pb geochronological studies, were carried out on the pegmatite. The results show that the Jiaolesayi pegmatite is syenite, without obvious compositional zoning in the outcrop. It exhibits a peraluminous, high-K calc-alkaline nature with strong depletions in Eu, Sr, Ba, Ti, and P, and high contents of Nb, Ta, Y, Ti, U, Th, and heavy rare earth elements (HREEs), which are primarily concentrated in allanite-(Ce), euxenite-(Y), limonite, thorite, and zircon. The geochemical and mineralogical features of the syenite pegmatite indicate it belongs to the euxenite-type in the rare element class (REE) of the NYF family, with the characteristic accessory mineral being euxenite-(Y). Its 10,000 Ga/Al ratios (2.46 to 2.96), Zr + Nb + Ce + Y contents (998 to 6202 ppm), Y/Nb ratios (0.62 to 0.75), and Yb/Ta ratios (0.80 to 1.49) show an affinity with A1-type granite. Zircons from the syenite sample yielded a weighted mean 206Pb/238U age of 413.6 ± 1.4 Ma, while the elevated U and Th concentrations in the zircons and Th/U ratios (0.04 to 0.16) suggest the possible influence of hydrothermal processes in the late-stage fractional crystallization. In the context of the regional tectonic evolution, the syenite pegmatite may have formed from a basic alkaline magma derived from an OIB-like melt with minor crustal contamination, under the post-collisional extension setting.\",\"PeriodicalId\":18601,\"journal\":{\"name\":\"Minerals\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.2000,\"publicationDate\":\"2024-08-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Minerals\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.3390/min14080805\",\"RegionNum\":4,\"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":"Minerals","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3390/min14080805","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
摘要
在柴达木盆地西北缘发现了大量伟晶岩。其中,位于泉吉丘陵(乌隆布鲁克微大陆)西北缘的焦勒萨依伟晶岩显示出稀有元素成矿潜力。对该伟晶岩进行了详细的野外调查以及矿物学、地球化学和锆石 U-Pb 地质年代研究。研究结果表明,焦勒寺伟晶岩为正长岩,在露头处没有明显的成分分带。其性质为过铝质、高K钙碱性,Eu、Sr、Ba、Ti 和 P 元素严重贫化,Nb、Ta、Y、Ti、U、Th 和重稀土元素(HREEs)含量较高,主要富集于绿帘石(Ce)、紫帘石(Y)、褐铁矿、透辉石和锆石中。正长岩伟晶岩的地球化学和矿物学特征表明,它属于 NYF 族稀有元素类(REE)中的埃克森岩型,其特征附属矿物为埃克森岩(Y)。其 10,000 Ga/Al 比率(2.46 至 2.96)、Zr + Nb + Ce + Y 含量(998 至 6202 ppm)、Y/Nb 比率(0.62 至 0.75)和 Yb/Ta 比率(0.80 至 1.49)显示与 A1 型花岗岩相近。从正长岩样品中提取的锆石的加权平均 206Pb/238U 年龄为 413.6 ± 1.4 Ma,而锆石中 U 和 Th 的浓度以及 Th/U 比值(0.04 至 0.16)的升高则表明在晚期分块结晶过程中可能受到热液过程的影响。从区域构造演化的角度来看,正长岩伟晶岩可能是在碰撞后的延伸环境下,由类似于 OIB 熔体的碱性碱性岩浆形成的,其中有少量地壳污染。
Geochemistry, Mineralogy, and Geochronology of the NYF Pegmatites, Jiaolesayi, Northern Qaidam Basin, China
A significant amount of pegmatite has been discovered on the northwest margin of the Qaidam basin. Among this, the Jiaolesayi pegmatite, located in the northwestern margin of the Quanji Massif (Oulongbuluke micro-continent), shows rare element mineralization potential. Detailed field investigations, along with mineralogical, geochemical, and zircon U-Pb geochronological studies, were carried out on the pegmatite. The results show that the Jiaolesayi pegmatite is syenite, without obvious compositional zoning in the outcrop. It exhibits a peraluminous, high-K calc-alkaline nature with strong depletions in Eu, Sr, Ba, Ti, and P, and high contents of Nb, Ta, Y, Ti, U, Th, and heavy rare earth elements (HREEs), which are primarily concentrated in allanite-(Ce), euxenite-(Y), limonite, thorite, and zircon. The geochemical and mineralogical features of the syenite pegmatite indicate it belongs to the euxenite-type in the rare element class (REE) of the NYF family, with the characteristic accessory mineral being euxenite-(Y). Its 10,000 Ga/Al ratios (2.46 to 2.96), Zr + Nb + Ce + Y contents (998 to 6202 ppm), Y/Nb ratios (0.62 to 0.75), and Yb/Ta ratios (0.80 to 1.49) show an affinity with A1-type granite. Zircons from the syenite sample yielded a weighted mean 206Pb/238U age of 413.6 ± 1.4 Ma, while the elevated U and Th concentrations in the zircons and Th/U ratios (0.04 to 0.16) suggest the possible influence of hydrothermal processes in the late-stage fractional crystallization. In the context of the regional tectonic evolution, the syenite pegmatite may have formed from a basic alkaline magma derived from an OIB-like melt with minor crustal contamination, under the post-collisional extension setting.
期刊介绍:
Minerals (ISSN 2075-163X) is an international open access journal that covers the broad field of mineralogy, economic mineral resources, mineral exploration, innovative mining techniques and advances in mineral processing. It publishes reviews, regular research papers and short notes. Our aim is to encourage scientists to publish their experimental and theoretical results in as much detail as possible. There is no restriction on the length of the papers. The full experimental details must be provided so that the results can be reproduced.