【摘要】 本文采用LA-ICP-MS方法对东昆仑东端温泉地区含榴辉岩的副片麻岩和花岗片麻岩进行了锆石U-Pb年代学研究。副片麻岩中锆石的年龄范围为2400⁴30Ma,峰值范围为2000¹200Ma,其中检测出少量新元古代（1.0⁰.9Ga）和早古生代（430Ma）的变质锆石,进一步限定了原岩的最早沉积时代为中元古代末期-新元古代早期(Pt_2-3),指示该沉积岩经历了新元古代早期和志留纪的变质作用。花岗片麻岩的原岩时代为900Ma,1件样品的锆石ε_Hf（t）值为-7.0⁺5.5,多数为负值,单阶段亏损地幔模式年龄为1.83¹.25Ga,指示它们主要是古老地壳（可能为金水口岩群变沉积岩）熔融的产物。新元古代早期的岩浆-变质事件与全球Rodinia超大陆的形成有关。虽然副片麻岩锆石只给出少量早古生代志留纪变质的信息,考虑到片麻岩中的榴辉岩形成于早古生代（450⁴30Ma）及邻区柴北缘高压-超高压变质带的演化历史,推测该地区片麻岩也经历了早古生代榴辉岩相变质作用,片麻岩与榴辉岩为原地关系。根据柴达木盆地南北两侧相似的早期构造演化可以推测柴达木盆地基底演化与其类似,至少经历了新元古代和早古生代两期构造活动,并非是元古代以来的稳定克拉通。更多还原

【Abstract】 The geochronology of the detrital zircons of the eclogite-hosting paragneiss and granitic orthogneiss in the Wenquan region,eastern part of the East Kunlun Mountains was studied by using LA-ICP-MS method in this paper. The ages of the detrital zircons of the paragneiss vary in a range of 2400 430 Ma,with a peak age value range from 2000 Ma to 1200 Ma,and minor metamorphic zircons of 1. 0 0. 9 Ga（Neoproterozoic） and 430 Ma（Early Paleozoic） also found,implying that the protolith of the paragneiss deposited from Late Mesoproterozoic to Early Neoproterozoic(Pt_2-3) and underwere metamorphism in Early Neoproterozoic and Silurian. Zircons of the granitic orthogneiss yield magmatic crystallization ages at 900 Ma,with ε_Hf（t） values of zircons from one sample varying from-7. 0 to + 5. 5,but most of them showing negative values,and their tDMvalues from 1. 8 Ga to 1. 3 Ga,demonstrating that the granites sourced mainly from the older basement melting（maybe metasediments from the Jinshuikou Group）.The Neoproterozoic magmatic and metamorphic events should be related to the formation of global Rodinia supercontinent. Although only minor zircons of the paragneiss contain the information of an Early Paleozoic metamorphic event,we infer this gneiss experienced Early Paleozoic eclogite-facies metamorphism,linking that the paragneisses bearing the eclogite formed in Early Paleozoic（450 ⁴30 Ma） as well as the in situ relationship between the gneiss and the eclogite,and tectonic evolution of HP-UHP belt in northern margin of the Qaidam Basin（QB）. Base on similar tectonic histories of both the southern and northern margins of the QB,we speculate that the basement of the QB suffered Neoproterozoic and Early Paleozoic tectonic events,and the basement itself was not a stable craton scince Proterozoic.更多还原