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东昆中构造混杂岩带主要由构造混杂岩块、古老基底岩系及原地沉积岩系组成,前人对其做了大量的研究。都兰县清水泉地区的东昆中构造混杂岩带中出露了一套变质沉积地层,作为清水泉蛇绿构造混杂岩的基质岩系,研究其形成时代、构造归属以及沉积物源,对于了解东昆中构造混杂岩带的时代归属及构造演化具有重要的意义。通过对变质沉积岩的碎屑锆石LA-ICP-MS U-Pb同位素年代学研究,获得碎屑锆石年龄范围为1847~437Ma,可进一步划分为1847~1729Ma、1 558~1400Ma、1 295~1 112Ma、965~749Ma、552~437Ma 5个年龄段。通过年代学、岩相学和区域对比研究,将浅变质沉积岩的形成时代限定为(490±2.6)~(427±4)Ma,为早古生代,归属于下古生界纳赤台群,同时进一步限定东昆中构造混杂岩带的基本构造格架形成于早古生代末期。
The structure of the complex karst belt in East Kunming consists mainly of tectonic mélanges, ancient basement rocks and in-situ sedimentary rocks, and a large number of studies have been done by them. A set of metamorphic sedimentary strata was exposed in the East Kunqu mid-structural mélange belt in Qingshuiquan area of Dulan County as a matrix rock series of ophiolite-type mélanges in Qingshui spring. Its formation age, tectonic belts and source of sediments were studied. It is of great significance to know the age and tectonic evolution of the tectonic melange belt in East Kunming. According to the U-Pb dating of detrital zircons from detrital sedimentary rocks, the detrital zircon ages range from 1847 to 437Ma, which can be further divided into 1847-1729Ma, 1558-1400Ma, 1295 ~ 1 112Ma, 965 ~ 749Ma, 552 ~ 437Ma 5 age groups. By means of geochronology, petrography and regional contrast study, the forming age of the shallow metamorphic sedimentary rocks is limited to (490 ± 2.6) ~ (427 ± 4) Ma, which belongs to the Early Paleozoic and belongs to the Lower Paleozoic Najiatai Group The basic tectonic framework that further restricted the formation of melange zones in East Kunlun was formed in the late Paleozoic.