PALEODRAINAGE PATTERNS ON THE CHUKCHI SHELF, NORTHWEST ALASKA

CHIRP subbottom data collected from the Chukchi shelf offshore of northwest Alaska reveal extensive paleodrainage networks that incised the margin during sea level lowstands. These channels are cut into folded Cretaceous bedrock strata and likely represent multiple sea level cycles. Several large incised valleys, 10s of km wide and up to 50m deep, as well as numerous smaller, individual channels have been identified. Possible sources of fluvial input include drainage from the Hope Valley to the south, as well as several smaller rivers on the northwest Alaskan coast such as the Utukok, Kokolik, Kukpowruk, and Kuk Rivers. This new data provides insight into paleodrainage patterns, as well as potential inputs from glacial meltwater and iceberg discharge derived from the northwest Alaskan margin. The large size of many of the channels and valleys implies there may have been higher discharge from the northwest margin than is observed in the present day. In addition, increasing evidence suggests that glaciation across the region, both on land and in ice shelves, may have been larger than previously thought.