Early Cretaceous Extension of the Yiwulüshan Metamorphic Core Complex
详细信息
- 责任者：Li Gang (College of Earth Sciences ; Jilin University ; Changchun 130061 ; China) ; Xu Zhongyuan
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(3)
- 关键词：变质核杂岩 ; metamorphic core complexes ; 伸展作用 ; extension ; 辽宁 ; Liaoning Province
- 页码：p.938-952
- 图表：illus., 1 table, 46 refs.
- 分类号：0802
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The deformation and distribution of tectonites along the Waziyu detachment fault and ductile shear zone in the lower footwall are analyzed by detailed field observations and laboratorial analysis.Based on the analyses of macroscopic deformation,microstructure and lattice preferred orientation of quartzs,we make sure that the evolution of the Early Cretaceous extension has the transition from the brittle-ductile deformation in high-greenschist faces to brittle deformation in low-greenschist faces,which shows the uplifting from shallow crust to near-surface.Analysizing the evolutionary processes of the Early Cretaceous extension combine the 40Ar/39Ar isotope ages of muscovites and other chronological dating in the ductile shear zone with characteristics of strata in the superposed extensional basin.The results support that the extension occurred at 132～117Ma and the deformation intensity was weakened gradually,moreover,the active period was longer in the north than in the south.The shear motion sense in the Yiwulüshan area and the movement of the Pacific Plate and the Izanagi Plate in the different Mesozoic periods suggest the Mesozoic extension of the Yiwulüshan area were controlled by the drifting of plates in the Western Pacific.
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