Sediment transport over the continental slope offshore northern Israel: an analysis by means of electron microscopy

Abstract

Seven subsamples from cores collected from the continental terrace offshore northern Israel were examined by TEM and SEM. These samples represent different sedimentary environments. The most homogeneous sample was subjected to various stresses, the highest corresponding to the overburden loading of a 1000-m-thick sedimentary column. The TEM photomicrographs were quantitatively analyzed using computerized methods. Detrital clay domains, mostly smectite, constitute up to 70% of the sediment bulk. Highly compacted silt-sized argillaceous clasts, lumps consisting of very dense, yet discernible clay domains and varying quantities of quartz grains and skeletal carbonate particles are randomly interspersed within the clay matrix. The clayey platelets and the argillaceous clasts are of east and north African origin, mostly transported by the Nile River, and in part by dust storms. The lumps originate from stiff, overconsolidated subbottom sediments detached and transported downslope by slumping. Current-transported quartz grains and skeletal debris from the continental shelf are mixed with these sediments. The analysis of the TEM and SEM photomicrographs supports the model of sediment dispersal patterns offshore northern Israel which was evaluated from radiographic studies of the cores and other data.