利用重力资料推算沉积盆地的基底密度

在大陆架上的沉积盆地,自由空间重力异常往往反映基底的起伏。因此,利用地震剖面把基底以上的物质层划分为不同密度的层、块,分别用二维多边形近似表示。计算所有这些多边形引起的重力值,可求出基底以上物质层引起的重力异常。根据此异常和实际观测的重力异常之差,即可推算沉积盆地内的基底密度分布。

Reckoning the density of the basement rook of sedimentary basin by gravity data

The gravity anomaly of free-space field generally indicates the ba-sement undulation in the sedimentary basin on continental shelf.We can divide the sedimentation overlying the basement into different density bands by adopting seismic section and approximately express them as 2-D polygons. The gravity anomaly caused by the sedimentation overlying the basement can be obtained by calculating the overall gravity anomaly of all polygons. Finally, the density distribution of the basement rock in this sedimentary basin can be deduced using the difference between the calculated gravity anomaly of the overlying sediment of the basement and the measured value.