Why does sediment on the floor of the Arabian Basin become thinner toward the south?

The sediment on the floor of the Arabian Basin becomes thinner toward the south primarily because the basin's floor is covered by a massive alluvial fan known as the Indus Cone. This feature is formed by sediments deposited by the Indus River, which originate in the north and decrease in thickness as they extend southward.12

While sediment thickness in the northern part of the basin reaches approximately 8,200 feet (2,500 metres), it tapers to about 1,600 feet (500 metres) in the south.2