Genesis of excess argon in phengite and significance of ^(40)Ar-^(39)Ar age spectra for omphacite:A case study on UHP eclogite of South Dabie Terrain,China  

作　　者：WANG Songshan, GE Ningjie, SANG Haiqing & QIU Ji1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2. Department of Earth and Space Science, University of Science and Technology of China, Hefei 230026, China Correspondence should be addressed to Wang Songshan 

出　　处：《Chinese Science Bulletin》2000年第15期1345-1351,共7页

摘　　要：The Ar-Ar dating of phengite and omphacite in ultrahigh-pressure (UHP) eclogite of Bixiling and Hengchong in the South Dabie Terrain shows that the content range of excess argon is as high as (0.4-1.3)×10 8 mol· g 1. The genesis of the excess argon is discussed. The Ar-Ar age spectra of omphacite could not support the opinion that the UHP metamorphism occurred in Caledon epoch and pre-Caledon epoch.The Ar-Ar dating of phengite and omphacite in ultrahigh-pressure (UHP) eclogite of Bixiling and Hengchong in the South Dabie Terrain shows that the content range of excess argon is as high as (0.4-1.3)×10 8 mol· g 1. The genesis of the excess argon is discussed. The Ar-Ar age spectra of omphacite could not support the opinion that the UHP metamorphism occurred in Caledon epoch and pre-Caledon epoch.

关 键 词：SOUTH DABIE TERRAIN ultrahigh-pressure metamorphics PHENGITE OMPHACITE excess argon. 

分 类 号：P597[天文地球—地球化学]