EROSIONAL MARKS ON CONSOLIDATED BANKS AND SLUMP BLOCKS IN THE RUPEN RIVER, NORTH-WEST INDIA

Erosional marks, including grooves, current crescents and flutes, are present on banks and slump blocks of the Rupen River on the semi-arid plains of north-west India. The channel has a width:depth ratio of 6, and is incised up to 8 m through well consolidated, fine-grained aeoli an sediment dated at approximate to 20-60 ka. Pedogenic carbonate nodu les embedded in the channel walls have localized scour, and reworked c arbonate particles probably promoted corrasion during strong seasonal flow. Similar erosional marks are apparently scarce on modern river ba nks, and a distinctive combination of conditions, including a consolid ated substrate and strong flow in a confined channel, is probably requ ired for their generation and preservation on channel walls and on slu mp blocks.