The Makran accretionary wedge:: sediment thicknesses and ages and the origin of mud volcanoes

The crust of the Arabian Plate below the Oman Abyssal Plain subducts to the north under the Eurasian continent, thereby building the Makran accretionary wedge. Within the thick sediments entering the subduction zone, a major unconformity was identified on reflection seismic profiles, In this paper we discuss the regional extent and age of this unconformity M(akran) separating a lower, shale and sand dominated deep sea sequence M1 of assumed Cretaceous to Early Neogene age from the overlying Upper Miocene to Recent clastic sequence M2. The mud-prone sediments of sequence M1 are interpreted to represent the main decollement of the Makran accretionary wedge. They are also regarded as the main source for rising mud diapirs and mud volcanoes along imbricated thrusts and anticlinal structures within the Makran wedge. This is supported by interpreted seismic offshore profiles and by biostratigraphic onshore investigations of mud material. (C) 2002 Elsevier Science B.V. All rights reserved.