摘要
造山带的伸展作用大致可以分为两种类型:(1)喜马拉雅型伸展,伸展限于上地壳,表现为规模有限的伸展断层,发生于俯冲—碰撞阶段;(2)科迪勒拉型伸展,整个地壳发生伸展,涉及拆离断层、沉积盆地、变质核杂岩的形成,发生于碰撞后阶段。对加厚地壳的热力学模拟,可以解释造山带挤压终止到伸展开始的时序与岩浆活动的关系。喜马拉雅型伸展伴随高压变质作用,并使变质岩系近等温减压;科迪勒拉型伸展与高温变质作用关系密切,伴随花岗质岩体的侵位,并使变质岩系近等温减压之后近等压冷却。
Extension of orogen may be roughly devided into two types: The first is Himalaya type-extension, which mainly consists of extensional faults of limited scale within the upper crustal level and occurred in subduction-collision stage. The second is Cordillera type-extension , which involves extension of the whole crust with development of detachment, sedimentary basins and metamorphic core complexes and occurred in post-collision stage. It is possible to explain relationship between magmatic activity and timing from the end of compression to the onset of extension in orogen through thermodynamic modelling of the thickened crust. Himalaya type - extension accompanied high-pressure metamorphism and caused isothermal decompression p-T-t paths. Cordillera type has a close relationship with high-temperature metamorphism and accompanied the emplacement of granitoid, giving rise to isothermal decompression and then isobaric cooling p-T-t paths.
出处
《地质科技情报》
CAS
CSCD
北大核心
1992年第3期10-18,共9页
Geological Science and Technology Information
关键词
褶皱带
伸展作用
地壳
演化
orogen, himalaya type-extension, cordillera type-extension, metamorphicm, p-T-t paths
