Arctic ocean geophysical studies: Chukchi Cap and Chukchi abyssal plain

Abstract

A bathymetric chart of the Chukchi Cap region was compiled with soundings obtained from Fletcher's Ice Island (T-3), as well as from other ice stations and from U.S. Navy icebreakers. New details of the Chukchi Cap are shown, including two submarine troughs on the southwest side. West of the Chukchi Cap, a small abyssal plain was found with a depth of 2230 m. This abyssal plain is connected through an abyssal gap with the deeper Canada Abyssal Plain.The prominent magnetic anomaly discovered during the drift of Station Charlie was crossed more recently by T-3 and by aeromagnetic flights. The continuity of the anomaly along the western and northern sides of the Chukchi Cap was further established by the new measurements. An interpretation was made of the anomaly as an expression of induced magnetization in basement rocks. The interpretation shows a basement ridge beneath the anomaly maximum at the edge of the Chukchi Cap. The Cap itself is interpreted as being underlaid by a 12 km thickness of sediments. Both magnetic and gravity data were used for an interpretation of total crustal thickness along the same section. Crustal thickness ranges from 18−12km beneath the Chukchi Cap to 32 km beneath the large basement ridge.