Abstract
The events which affected the Iranian sector of the Southern Tethyan margin of the Arabian continent during the Cretaceous differed from those that took place in Oman, although they were clearly related to them. Extensional faulting, parallel to the shelf margin, commenced locally in the Cenomanian and culminated later in the Cretaceous with the expulsion of mantle material to the surface. This engulfed the shelf edge before gliding southwestwards over a complementary intra-shelf basin. These events took place progressively later towards the north-west, and are interpreted as an unsuccessful attempt to develop a spreading axis along the continental margin. They were followed by a return to shelf sedimentation at the southern edge of Tethys, which closed finally in the early Miocene. It is suggested that the Oman and Iranian sectors of the Arabian margin were offset some 300 km by a north-south transform fault, and that the differences between the two regions were therefore due to attempted spreading in different tectonic environments in the late Cretaceous.