Paleoproterozic ～2.0Ga Meta-Granite in the Liangcheng Area, Inner Mongolia: Constraint on Regional Ultra-High Temperature Metamorphism
详细信息
- 责任者：Zhang Huafeng (School of Earth Sciences and Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Luo Zhibo
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(7)
- 关键词：变花岗岩 ; apogranite ; 超高压变质作用 ; ultrahigh pressure metamorphism ; 内蒙古 ; Inner Mongolia
- 页码：p.2391-2404
- 图表：5 illus., 4 tables, 76 refs.
- 分类号：0802
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The Liangcheng area is located in the central-north of the North China Craton (NCC),easternmost portion of the khondalite belt,in which voluminous Paleoproterozoic meta-granites are exposed and can be divided into three groups of monzogranite (Ⅰ),anatectic granite (Ⅱ) and charnockite(Ⅲ) in terms of geology and mineralogy.Our focus is on the Group Ⅰ which is dominated by mineral assemblages of plagioclase,K-feldspar,quartz,biotite,and garnet.In terms of mineral assemblages and geology,they are distinctive from the ca.1.93Ga anatectic granites (Group Ⅱ) which were generated by partial melting of the khondalite.LA-ICP-MS zircon U-Pb dating showed that the Group Ⅰ were emplaced approximately ～ 2.0Ga ago and metamorphosed at 1.95 ～ 1.90Ga ago,with magmatic zircons being crystallized at 856 ～ 964℃ (averaged 912℃) and 861 ～ 900℃ of the metamorphic zircons.The results indicate that the Liangcheng meta-granite (Group Ⅰ),together with wall rocks of the khondalite series,were metamorphosed at 1.95 ～ 1.90Ga ago,under ultra-high temperature.In situ Lu-Hf isotopic compositions of zircon,integrated with whole rock Nd isotopes and geochemistry,suggest that the Liangcheng 2.0Ga meta-granite was not S-type granite and dominantly generated by partial melting of the Archean and Paleoproterozoic lower crust.