混合网格方法在巴巴多斯增生复合体热演化有限元模拟中的应用

THERMAL MODELING OF THE BARBADOS ACCRETIO-NARY COMPLEX BY FINITE ELEMENT METHODOF MlXED GRIDS

为研究巴巴多斯增生复合体构造热演化的过程，采用空间坐标系和质点坐标系相结合的方法，在处理构造运动和变形的平流热效应时，并用变网格法及固定网格中的迎风法，成功地对该区域进行了二维有限单元法热模拟。计算结果表明，巴巴多斯增生复合体前弧下存在较高孔隙压力（约为岩体压力值的０．８）和一定摩擦生热（等效摩擦系数约为０．１７），俯冲沉积物压密和脱水排出的水沿脱顶断层从变形前锋流出是解释该区地热特征的必要条件。

In order to study the thermal evolution of the Barbados accretionary complex,spatial coordinate and material coordinate are combined to handle the problem ofadvective heat transfer produced by tectonic movements. Upwind method is used inspatial coordinate of fixed grids, while grids are changing with deformation in materialcoordinate. Two-dimensional finite element modeling indicates that beneath the forearcof the prism, relatively high pore pressure (about 0.8 of lithostatic pressure) and small,but not negligible friction (effective friction of 0.17) may exist. Flow of fluid fromcompacted and dehydrated subducted sediments along the decollement to thedeformation front is critical for interpretation of the local heat flow pattern.