刘军平, 胡绍斌, 田素梅, 卢晓萍, 孙柏东, 俞赛赢, 朱勋早, 孙鹏, 王晓峰. 2019: 滇西南涧地区无量山岩群变质英安岩锆石U-Pb年龄及其构造意义. 地质通报, 38(8): 1327-1334.
    引用本文: 刘军平, 胡绍斌, 田素梅, 卢晓萍, 孙柏东, 俞赛赢, 朱勋早, 孙鹏, 王晓峰. 2019: 滇西南涧地区无量山岩群变质英安岩锆石U-Pb年龄及其构造意义. 地质通报, 38(8): 1327-1334.
    LIU Junping, HU Shaobin, TIAN Sumei, LU Xiaoping, SUN Baidong, YU Saiying, ZHU Xunzao, SUN Peng, WANG Xiaofeng. 2019: U-Pb ages of zircon from metamorphic dolomite of the Wuliangshan Rock Group in Nanjian area, western Yunnan, and its tectonic significance. Geological Bulletin of China, 38(8): 1327-1334.
    Citation: LIU Junping, HU Shaobin, TIAN Sumei, LU Xiaoping, SUN Baidong, YU Saiying, ZHU Xunzao, SUN Peng, WANG Xiaofeng. 2019: U-Pb ages of zircon from metamorphic dolomite of the Wuliangshan Rock Group in Nanjian area, western Yunnan, and its tectonic significance. Geological Bulletin of China, 38(8): 1327-1334.

    滇西南涧地区无量山岩群变质英安岩锆石U-Pb年龄及其构造意义

    U-Pb ages of zircon from metamorphic dolomite of the Wuliangshan Rock Group in Nanjian area, western Yunnan, and its tectonic significance

    • 摘要: 滇西南涧-云县一带广泛出露的无量山岩群是一套与三江特提斯造山带密切相关的中低变质沉积岩夹火山岩系,其形成时代、沉积充填序列及大地构造属性一直存在争议。出露于南涧县公郎乡一带的无量山岩群发育有厚数厘米的变质英安岩夹层。对变质英安岩进行LA-ICP-MS锆石U-Pb定年,分别获得428.7±8.7Ma的岩浆结晶年龄和338~387Ma、250.5±8.1Ma、146.0±6.0Ma的变质年龄。认为无量山岩群原始沉积岩形成于志留纪,在古特提斯洋俯冲过程中,经历古生代造弧而发生区域变质作用,在白垩纪受热事件影响而发生热变质作用;同时还获得2034±22Ma、1140±16Ma、731±15Ma及469~522Ma的单颗粒锆石年龄,这些年代峰值与整个扬子陆块西缘获得的前寒武纪、古生代构造热事件年龄及分布特征基本可以对比;记录了Columbia、Rodinia和Gondwana超大陆的形成与裂解过程。

       

      Abstract: The Wuliangshan Rock Group, which is widely exposed in the Nanjian-Yunxian area of western Yunnan, is a set of low and medium metamorphic sedimentary rocks intercalated with volcanic rocks closely related to the Sanjiang Tethys orogenic belt. Its formation age, sedimentary filling sequence and tectonic attributes have been controversial. The Wuliangshan Rock Group, exposed in Gonglong County and Nanjian County, has a metamorphic ananite intercalation several centimeters thick. The zircon U-Pb LAICP-MS dating of the metamorphic andesite Sample was carried out, and the magmatic crystallization age of 428.7±8.7Ma and the metamorphic age of 338~387Ma, 250.5 ±8.1Ma and 146.0 ±6.0Ma were obtained respectively. It is considered that the original sedimentary rocks of the Wuliangshan Rock Group were formed in Silurian and experienced regional metamorphism in the Palaeozoic arc forming process during the Paleo-Tethys Ocean subduction and thermal metamorphism in the Cretaceous period due to thermal events. At the same time, the single grain ages of 2034±22Ma, 1140±16Ma, 731±15Ma and 469~522Ma were obtained, which can be compared with the Precambrian, Paleozoic tectonic caloric event ages and distribution characteristics obtained from the western margin of the Yangtze block. It underwent the formation and breakup of Columbia, Rodinia and Gondwana supercontinent.

       

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