Marine Platform of Probable Sangamon Age, and Associated Terrace Deposits, Cape Thompson Area, Northwestern Alaska

Abstract

Reports geomorphic studies, as part of the US Atomic Energy Commission's investigations in this area 1958-1962. A coastal terrace, observed and measured along a 20-mi section crossing Ogotoruk Creek, is described and its origin, age, and morphology discussed. The feature is complex, consisting of a marine platform planed across bedrock, overlying marine and beach deposits, and a depositional upper surface of nonmarine sediments which coincides in area and configuration with the platform, possibly as a result of factors unique to polar areas. The marine platform and gravels record the last high stand of sea level, 28-40 ft above the present, which occurred about 38,000 yr ago. Other evidence in the area indicates still higher seas in earlier times.