Deformation and Metamorphism Sequence of Bikou Terrane in the Northwest Margin of Yangtze Plate: Implications for Extension Collapse and Transition of Songpan-Garze Orogenic Belt

详细信息   

• 责任者：Liu He (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Yan Danping
• 刊名：Acta Geologica Sinica
• 出版年：2008
• 卷期：82(4)
• 关键词：变质作用 ; metamorphism ; 变形 ; deformation ; 扬子地台 ; Yangtze Platform
• 页码：p.464-474
• 图表：3 illus., 7 tables, 2 plates，43 refs.
• 分类号：0300
• issnNo：ISSN0001-5717
• isbnNo：CN11-1951/P

摘要

///The Bikou terrane lies at the junction of Qinling orogenic belt, Songpan-Garze orogenic belt and Yangtze Plate.Three tecton-stratigraphic units have been identified within this terrane: 1) the Neoproterozoic basement complex, composed mainly of volcanic rocks of Bikou Group and turbidite of Hengdan Group, has weak deformation in the core but strong ductile shear deformation along the margin; 2) the Paleozoic middle ductile slab is composed of Silurian-Devonian mylonite and phyllonite, in which develops three stages of foliations (S1,S2,S3).The middle ductile slab underwent metamorphism of mid-greenschist facies; and 3)  the Mesozoic sedimentary cover, including Triassic Guanjiagou Formation to the north of Bikou terrane and Jurassic-Cretaceous in some small areas, is characterized by brittle fault and fracture belt without metamorphism.