Reconstruction of sedimentary basins formed on ductile substrata

Abstract

A simple reconstruction technique for sedimentary basins formed on ductile substrata is introduced. This technique is based on backstripping method and assumes the preservation of bed lengths. First, a seismic section for a sedimentary basin is interpreted and converted into a depth section. The interpreted horizons are divided by tick marks, from the basin axis out toward the basin margins, into a number of equally-spaced line segments. Then, each sediment layer is removed by moving the tick marks on the lower boundary of the layer to the corresponding tick marks on the upper boundary, thereby preserving the bed lengths. Decompaction correction is made to add the amount of expansion after removal of each sediment layer. The seafloor or bathymetry is adjusted after decompaction correction. Backstripping, decompaction correction, and seafloor adjustment are repeated until the deepest sediment layer is left in the basin. This technique is applicable to the analysis of monotonously subsiding basins formed by withdrawal of ductile substrata. It may also be applicable, to a limited extent, to intracratonic basins with simple subsidence histories.