Vertical Structure of Near-Surface Sediments in the Central Parts of the Yaghan and Scan Basins (Scotia Sea)

Resumo

The structure of the sediment sequence of the Scotia Sea is the basis for reconstructing the geological history of the development of its floor in the late Quaternary. One of the most important elements of the floor of the southern Scotia Sea is the Scan Basin, the formation of which played a substantial role in the breakup of the American–Antarctic continental bridge that connected the Bruce and Discovery banks. By now, the main parameters of the sediment sequence in the Scan Basin have been reconstructed, but the literature reflects the lack of data on the upper part of the section. On an observation profile, the Spanish R/V Hesperides, using a TOPAS PS 18/40 high-resolution seismic profiler, distinguished three beds in the central part of the basin. The total mean thickness of the first reflector is 3.7 ms; the second, 2.3 ms; and the third, 1.8 ms. The beds have a relatively consistent thickness and are distinctly traced along the profile. The literature data on the sedimentation parameters make it possible to estimate the total mean deposition time for the first bed of 133 ka; the second, 84 ka; and the third, 64 ka; the total mean sediment accumulation time for all three beds is 281 ka.