摘要
大别山造山带之所以成为造山带研究热点,是因为出露了世界上面积最大的以柯石英榴辉岩(见封3照片1)(Xu Z.Q.1987,Wang X.et al.1989.Okay et al.1989)和含金刚石榴辉岩(Xu S.T.et al.1992)为代表的超高压(UHP)
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 crust seismic velocity model of vertical layering and horizontal blocks as well as a Poisson's ratio section were obtained. From 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 nappe-sheets structure and, the middle-lower crust, ductile deformed layers. The lower crust of the Dabieshan Belt appears to be acidic in composition as a whole. The Dabieshan'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 6-8 km deep under the Dabieshan mountain.
出处
《中国地质》
CAS
CSCD
1997年第1期32-37,共6页
Geology in China
基金
地矿部"八五"深部地质研究专项
