Keynote Speech: Prof. J. Fred Read (Virginia Tech, USA)

Carbonate platform types relevant to the Jurassic-Cretaceous passive margins of the region include homoclinal ramps, with uniform gentle slopes on the deep ramp of 0.1 degree to a few degrees, along with low energy, distally steepened ramps, in which the gently sloping deep ramp distally steepens (up to several degrees) into the basin, and rimmed margins, characterized by reefal rims and steeper marginal slopes. Modern analogs for interiors of the immense, relatively flat topped platforms that typify the Arabian Peninsula are lacking. Differentiation of the platform interiors generated large intrashelf basins and source rocks in silled, stratified settings, bordered by basinward prograding ramp systems. Low sedimentation rate in platform interiors, differential subsidence and siliciclastic poisoning all may have played a role in formation of the intrashelf basins.