%0 Journal Article
%T U-Pb zircon dating constraints on formation time of Qilian high-grade metamorphic rock and its tectonic implication<br>U-Pb zircon dating constraints on formation time of Qilian high-grade metamorphic rock and its tectonic implications
%A XU WangChun
%A ZHANG HongFei
%A LIU XiaoMing
%A <br>XU
%A WangChun
%A ZHANG
%A HongFei
%A LIU
%A XiaoMing
%J 科学通报(英文版)
%D 2007
%I 
%X In order to constrain the formation time of high-grade metamorphic rocks in the Qilian Mountains, U-Pb zircon dating was carried out by using LA-ICPMS technique for a paragneiss of the Hualong Group in the Qilian Mountains basement series and a weakly foliated granite that intruds into the Hualong Group. Zircons from the paragneiss consist dominantly of detrital magma zircons with round or sub-round shape. They have 207Pb/206Pb ages mostly ranging from 880 to 900 Ma, with a weighted mean age of 891 ±9 Ma, which is interpreted as the magma crystallization age of its igneous provenance and can be taken as a lower age limit for the Hualong Group. Magma crystallization age for the weak-foliated granite is 875±8 Ma, which can be taken as an upper age limit for the Hualong Group. Accordingly, the formation time of the Hualong Group is constrained at sometime between 875 and 891 Ma. A few zircons from both paragneiss and weak-foliated granite display old inherited ages of 1000 to 1700 Ma and young metamorphic ages of Early Paleozoic. The zircon age distribution pattern confirms that the Qilian Mountains and the northern margin of Qaidam Basin had a united basement, with geotectonic affinity to the Yangtze Block. The results also reveal that sediments of the Hualong Group formed by rapid accumulation due to rapid crustal uplift-erosion. This process may result from intensive Neoproterozoic orogenesis due to assembly of the suppercontinent Rodinia. Supported by the National Natural Science Foundation of China (Grant Nos. 40234052 and 40521001) and Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0441)
%K zircon U-Pb age
%K high-grade metamorphic rock
%K geotectonic affinity
%K Qilian Mountains<br>祁连山
%K 高级变质岩
%K 形成时间
%K U-Pb锆测年
%K 地质构造
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=01BA20E8BA813E1908F3698710BBFEFEE816345F465FEBA5&cid=96E6E851B5104576C2DD9FC1FBCB69EF&jid=DD6615BC9D2CFCE0B6F945E8D5314523&aid=9103E5B5D832F5D809539A9CFF83F833&yid=A732AF04DDA03BB3&vid=286FB2D22CF8D013&iid=E158A972A605785F&sid=20ADD38F841C6A4B&eid=E49BED2EA9A8956B&journal_id=1001-6538&journal_name=科学通报(英文版)&referenced_num=3&reference_num=38