摘要
1994年完成的大别造山带深地震测深剖面（全长420km）穿越了华北地块，大别造山带和扬子地块三个构造单元．获得了垂向成层、横向分块的地壳纵、横波速度结构．结合地质、地球化学研究成果，大别山地壳可分为三层：上地壳是多重叠覆的构造岩石层，中地壳为韧性变形层，下地壳整体成分偏酸性．大别山地表及浅部的超高压变质岩石具有典型的薄皮构造特征．本文提出大别山不同期双向俯冲造山模式和超高压变质岩石的反向加楔退拔折返机制；大别山腹地至今仍保留6-8km厚的山根．
Seismic sounding data along a 420km long profile was collected in 1994. From north to south the profile goes across three tectonic units, namely North China Block,Dabieshan Orogenic Belt and Yangtze Block. By forward modeling, a vertically layered and laterally blocked crust velocity model as well as its Poisson's ratio section was obtained. According to the seismic experiment associated with geological and geochemical research, the following inferences are drawn. The crust can be divided into three layers. The upper crust exhibits a multiple napped-sheets structure and the middle crust ductile deformed layers. The lower crust of the Dabieshan Belt appears to be acidic in composition as a whole. The Debieshan's UHP metamorphic rocks are characterized by a typical thin skin sheet structure. Anasynchronous dual subduction mountain-building model and opposite wedging and drawing exhumation machanism of the UHP rocks are suggested. It is quite evident that there exists a mountain root of about 6-8km thick under the Dakieshan mountain.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第3期349-361,共13页
Chinese Journal of Geophysics
基金
地质矿产部"八五"深部地质专项资助!85-06-217
关键词
大别造山带
超高压质带
地壳速度结构
动力学
Debieshan orogenic belt, UHP belts, Seismic sounding, Crust velocity levels, Dynamics.
