DISCOVERY OF THE PALAEO-INDUS DELTA-FAN COMPLEX

The Indus River carries sediments from the western Himalaya and deposi ts some of these as channel and floodplain sediments or molasse, The r est of its load forms the Indus delta at the margin of the Indian Ocea n. The Indus delta passes some of its sediments to be deposited as Ind us submarine fan turbidites. Thus, as elsewhere, Himalayan molasse, de lta, and fan deposition are related in time and space, However, when w e examine fluvial and marine age-range data of the older Indus deposit s, in terms of this sedimentary assemblage, a major portion of its mar ine record is missing. The oldest known molasse along the Indus suture zone, and in the foredeep are middle Eocene and late Palaeocene in ag e, respectively. A recent synthesis of sedimentation in the northern I ndian Ocean, however, shows that turbidite sedimentation started aroun d early Miocene in the modern Indus fan, and even later in the Bengal fan. Where are the Palaeogene Indus delta and fan sediments? We sugges t herein that these are preserved as the Palaeogene siliciclastic Khoj ak Formation in the Katawaz Basin and eastern Makran.