New ^(40)Ar/^(39)Ar Results to the Avanavero Dolerite,Guiana Shield in the Roraima State,Brazil  

作　　者：Gabriela Perlingeiro Umberto G.Cordani 

机构地区：[1]University of Queensland(Australia) [2]University of Sao Paulo and Paulo Vasconcelos,University of Queensland

出　　处：《地学前缘》2009年第S1期207-207,共1页Earth Science Frontiers

摘　　要：⁴⁰Ar/³⁹Ar dating of plagioclases,pyroxene or/and amphibole of separated grains from Avanavero Dolerite located in the Guiana Shield,in Roraima State,Brazil yield plateau ages ranging from 1840±50 Ma to 1179±10 Ma.The highest ages are interpreted to represent the emplacement of dolerites within the sandstones ofRoraima Supergroup,while the younger results reveal partial argon loss during the cooling history of the samples related to a large

关 键 词：⁴⁰Ar/³⁹Ar GEOCHRONOLOGY Avanavero DOLERITE Guiana SHIELD Roraima 

分 类 号：P597.3[天文地球—地球化学]