DEFORMATION AND DIAPIRISM OF SOFT STRATA IN THE YELLOW RIVER DELTA

Diapir bodies are distributed in the lower slope of the abandoned delta lobe in the north of the Yellow River delta, the formation mechanism of which is related to the marine erosion and greatly different from that in the Mississippi delta. The interpretation of a typical sub-bottom profile reveals that the diapir of the Yellow River delta resulted from the interior deformation of soft prodelta layers at the delta front. The special stratification structure leads to the existing of a low-pressure zone on the soft layers, which contributes partly to the protuberant topography of the upper prodelta. After the river channel shifted, the discharging center of pressure was generated from the seabed erosion, on which the diapir came into being. As the seabed erosion rate decreases, the diapir shrinks gradually and disappears finally due to the erosion. The deformation of the soft strata and diapir will do great harm to the marine engineering especially in the delta region with such special stratification structures.