Growth Structures and Unconformities in the Upper Evaporites, Red Sea

This chapter shows seismic reflection images of the Red Sea. In these images, the top of the evaporites is marked by a prominent reflection called 'S'. Deep-seismic images show the evaporites to be either massive or layered. The former are suspected to represent massive halite deposits, while the latter represent halite interlayered with anhydrite and shale, as found at the deep sea drilling sites in the Red Sea. Evaporite reflections within and around the anticline vary in dip. This is evidence that the evaporites were mobile during deposition, as well as after deposition. On the right around shot point (SP) 400, dipping evaporite reflections beneath S show that the S reflection is locally an unconformity. Such flat unconformities in evaporites in the Mediterranean have been interpreted as due to surf erosion when the sea level was depressed and such areas were in the littoral zone, in contrast with more rugged unconformities indicating fluvial erosion.