A bathymetric chart of the Chukchi Cap region was compiled with soundings obtained from Fletchers 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. 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. Crustal thickness ranges from 18 12 km beneath the Chukchi Cap to 32 km beneath the large basement ridge. During April and May, 1962, ice vibrations in the frequency range from 0.1 to 100 cps were measured aboard drifting ice island yARLIS II in the central Arctic Ocean.
Semi-annual technical summary rept. 1 Jan-30 Jun 65,