Morpho-acoustic and sedimentologic characteristics of the Indus Fan

The upper Indus Fan is characterized by an average 1:500 gradient, channels with 100 m high levees, several continuous subbottom reflectors on 3.5-kHz records, and generally fine-grained sediments. Multichannel seismics show the levee complexes typified by overlapping wedge-shaped reflection sets and channel axis by high-amplitude discontinuous reflections. The middle fan has 1:500-1:1000 gradients and channels with similar to 20 m high levees. The lower fan has gradients less than 1:1000, channels with 8-20 m high levees, few or no subbottom reflectors on 3.5 kHz records, and high sand content. Besides the dominant unchannelized turbidity currents, channelized and overbank flows also played a significant role in the sedimentation of the lower fan.