Age of Anzishan granulites in the Mianxian-Lueyang suture zone of Qingling orogen:With a discussion of the timing of final assembly of Yangtze and North China craton blocks  

作　　者：ZHANG Zongqing ZHANG Guowei TANG SuohaiV XU Jifeng YANG Yongcheng WANG Jinhui 

机构地区：[1]Institute of Geology,Chinese Academy of Geosciences,Beijing 100037,China [2]Department of Geology,Northwest University,Xi’an 710069,China [3]Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China [4]Shaanxi Institute of Regional Geology and Mineral Resources,Xian-yang 712000,China

出　　处：《Chinese Science Bulletin》2002年第22期1925-1930,共6页

基　　金：The work was supported by the National Natural Science Foundation of China(Grant Nos.40072071and 49732080).

摘　　要：Many granulite blocks have been recently dis-covered in the Anzishan area, Mianxian County, ShaanxiProvince, in the central segment of the Manxian-Lueyangsuturc zone. Sm-Nd isochron and 40 Ar39 Ar ages of mineralsamples of granulites from this area are reported in the note.The granulite mineral samples give a Sm-Nd isochron age oft=(206 ± 55) Ma (2σ), with INd = 0.51302±7(2σ) and MSWD =1.6, and a biotite 40Ar/39 Ar plateau age of (199.7±l.7) Ma(2σ). The formation and uplift of the granulites were relatedto subduction of the Yangtze block beneath the SouthQinling microcontinent and their collision and the finalamalgamation of the Yangtze and Sino-Korean craton blocksin the Indosinian, and their age is consistent with or close tothose of the Dabie ultrahigh-pressure and high-pressuremetamorphic rocks, so have great tectonic significance.Many granulite blocks have been recently discovered in the Anzishan area, Mianxian County, Shaanxi Province, in the central segment of the Mianxian-Lueyang suture zone. Sm-Nd isochron and 40Ar/39Ar ages of mineral samples of granulites from this area are reported in the note. The granulite mineral samples give a Sm-Nd isochron age of t=(206 ±55) Ma (2σ), with INd = 0.51302±7(2σ) and MSWD = 1.6, and a biotite 40Ar/39Ar plateau age of (199.7±1.7) Ma (2σ). The formation and uplift of the granulites were related to subduction of the Yangtze block beneath the South Qinling microcontinent and their collision and the final amalgamation of the Yangtze and Sino-Korean craton blocks in the Indosinian, and their age is consistent with or close to those of the Dabie ultrahigh-pressure and high-pressure metamorphic rocks, so have great tectonic significance.

关 键 词：isotope GEOCHRONOLOGY GRANULITE QINLING orogen. 

分 类 号：P588[天文地球—岩石学]