大别造山带上部地壳结构的有限差分层析成像

将有限差分层析反演方法用于大别造山带人工地震测深剖面上部地壳初至波的走时层析成像，得到这一剖面上部地壳横向不均匀结构图像表明，在南大别地区的超高压变质带发现榴辉岩相岩石，其下方3km深度以内的基底仍具有大陆地壳构造中正常的结晶基底速度（6．00km／s左右）；北大别地区在整个上地壳保持正常的速度，而在超高压带下方3km深度以下为6．20-630km／s的相对高速异常区，这一现象可能与超高压变质岩的含量增大有关．同时还表明，南大别和北大别之间至少在上地壳已有明显差异，它们之间的水吼一五河断裂可能是大别造山带内部的主要构造分界线．

FINITE-DIFFERENCE TOMOGRAPHY OF UPPER CRUSTAL STRUCTURE IN DABIESHAN OROGENIC BELT

The finite-difference inversion method is used to the tomography of travel time of the first arrival in upper crust on the deep seismic sounding profile across the Dabieshan orogenic belt. The lateral inhomogeneous structure of upper crust shows that although the ecologite rocks were discoveried in the south-Dabie ultra-high pressure (UHP) metamorphic belt, the basement above the depth of 3km has the normal velocity of the crystalline basement in the continental crust (6.00km / s). The normal velocity is retained in the whole upper crust of the north-Dabie area. However,there is a relative high velocity anomaly region beneath the depth 3km in the UHP area, which may related to the medium with high-content UHP rock, and the significant difference betWeen the north-Debie and south-Dabie exists in upper crust at least. Therefore, the Shuihuo-Wuhe fault, the boundary between the north and south-Debie, may be the major tectonic boundary inside the Debieshan orogenic belt.