Geological and geophysical investigations of the crustal structure and geological processes of the Victoria Land basin and the Iselin Bank areas

The geological structure and processes of parts of the Ross Sea continental shelf and margin was investigated via the USGS research ship S.P.LEE. The geological structure was investigated from the surface sediments to the deep crustal structure and tectonic history of the Victoria Land basin (a major sedimentary basin underlying the western Ross Sea) and the Iselin Bank. The nature of the continent -ocean boundary of the western Ross Sea was investigated with a wide range of geophysical and geological techniques used including multichannel seismic reflection data (2.350 kilometers), sonobuoy seismic (39 stations), high resolution seismic reflection (1,850 kilometers), 3.5 kilohertz and 12 kilohertz bathymetry (4,500 kilometer), magnetic gradiometer (3,100 kilometers) and gravity data (3,950 kilometers). Sampling operations included 3 meter gravity coring (15 cores from 10-258 cm in length), chain bag dredgin (two stations with excellent recovery) and measuring heat flow (3 sites). A detailed high-resolution seismic-reflection survey of an area of irregular seafloor bathymetry was also conducted. During the cruise, analytical measurements of organic gas concentrations and sediment shear strength were routinely made on the gravity cores immediately after core recovery. Thermal conductivity determinations were also done on cores from heat flow stations.