. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . 50 _l ••••••••••• ••••••• Kilometers •• • !*fll*t •«•• ••••••••••••••• ••••••••••• •**•••• ••••••••••••*•••• j_ ± Figure 15-la. Cross-hatched area of Fig. 15-1, showing closely spaced sampling grid offshore at Nome. 15-4). These geologic hazards may pose problems for the future development of offshore resources in Norton Basin. SEDIMENTARY PROCESSES Yukon Delta processes The Yukon River drains an area a little less than 900,000 km^, providing a water discharge of approxi- mately 6,000 m^
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . 50 _l ••••••••••• ••••••• Kilometers •• • !*fll*t •«•• ••••••••••••••• ••••••••••• •**•••• ••••••••••••*•••• j_ ± Figure 15-la. Cross-hatched area of Fig. 15-1, showing closely spaced sampling grid offshore at Nome. 15-4). These geologic hazards may pose problems for the future development of offshore resources in Norton Basin. SEDIMENTARY PROCESSES Yukon Delta processes The Yukon River drains an area a little less than 900,000 km^, providing a water discharge of approxi- mately 6,000 m^/sec and a sediment load of 70-90 million mt per year (Dupr6 and Thompson 1979, Cacchione and Drake 1979a). The sediment load, almost 90 percent of all sediment entering the Bering Sea, is composed mainly of very fine sand and coarse silt with very little clay. The Yukon Delta plain, like many deltas, is fringed by prograding tidal flats and distributary mouth bars. The delta front and prodelta are offset from the prograding shoreline by a broad platform (referred to as a subice platform) 30 km at its widest reach. This platform appears to be related to the presence of shorefast ice that fringes the delta for half the year. The term "delta front" describes the relatively steep margin of the offshore delta environment charac- terized by rapid deposition of sediment in water 2-10 m deep. The prodelta, an area of extremely gentle slopes, marks the distal edge of the deltaic sediments extending as far as 100 km offshore. Processes on the Yukon Delta and offshore operate under seasonal regimens (Dupr^ and Thompson 1979). The ice-dominated regimen begins with freeze-up in late October or November. Shorefast ice extends 10-40 km offshore, where it terminates in a series of pressure ridges and shear zones formed by the interaction of
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