Abstract: Variations in Coastal Environments and Beach Morphology of Northern Alaska

E. H. Owens

The characteristics of beach environments on the North Slope of Alaska from Cape Thompson to Demarcation Point are identified in terms of (1) the barrier systems, (2) the variability of barrier and beach morphology, and (3) the variability of energy levels. The Beaufort Sea coast has three distinct barrier systems that have irregular plan forms, rarely have dunes, and are washed over during storms. These are in marked contrast to the three major cape systems and the Point Hope foreland on the Chukchi coast, where the barriers are continuous, straight, and have low dunes in the backshore. The differences are related directly to variations in both the frequency and magnitude of peaks in the wave-energy spectrum. Longshore sediment-transport processes on the Chukchi Sea coast are more continuous during the open-water season, whereas energy levels are both lower and more variable on the Beaufort Sea coast. Superimposed on the regional-scale variability between these two coastal environments is a change in morphologic characteristics eastward from Cape Thompson that is related to a progressive decrease in wave-energy levels. Beach morphology changes from a profile with a single, simple berm to a more complex series of three or more ridges formed by wave or ice action. The continuous littoral transport during op n water changes to a series of pulses, related to periods of higher energy conditions, resulting in an increase in beach perturbations eastward. A model relates littoral energy levels to variations in beach and barrier morphology.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC