Arctic Geophysics

Abstract

The modern phase of geophysical research began at Barrow in 1944 with exploration of Naval Petroleum Reserve No.4. The asymmetric sedimentary basin below the Arctic coastal plain was discovered and defined, using gravity, magnetic and seismic methods. A regional gravity survey, which revealed a large negative Bouguer anomaly over the Brooks Range, was extended seaward and indicated an extension of the Range beneath the Chukchi Sea to join with the Chukchi-Anadyr fold belt of Siberia. A marine geophysical program began on drifting station ARLIS II in 1961 and continued on T-3 ice island, to study configuration and sedimentation of the Arctic Basin floor drifting over the Lomonosov Ridge, Alpha Cordillera, Wrangel Abyssal Plain and Siberia Abyssal Plain. Experiments were run to measure seismic noise on the ocean floor, modified gravity waves were interpreted as ocean swell modified by the influence of the pack ice. Since 1963, using a precision depth recorder, soundings from T-3, other drifting stations and nuclear submarines form the basis for present concepts of Arctic Ocean shape and structure. The Arctic Mid-Ocean Ridge is seismically active and along it sea-floor spreading is believed to be taking place at present. More geophysical data are needed to decide the merit of this concept.