Physical properties of late Quaternary marine sediments along the southern Argentine margin

Variations of the physical properties of late Quaternary seafloor sediments reflect changes in their lithologies, accumulation/consolidation histories, and the environmental processes that influence these sediments. Physical property variations also determine the characteristics of acoustic reflections observed on high-resolution seismic profiles of the seabed. During oceanographic cruise TN-372 aboard the RV Thomas G. Thompson, a suite of forty-two gravity and piston cores were collected from the southern Argentine margin. Their physical properties (i.e., bulk density, water content, compressional wave velocity, and magnetic susceptibility) were determined using a multi-sensor core logger. Several representative cores were subsequently split, allowing their sediments to be described and scanning XRF elemental data to be obtained. Discrete samples were taken from the cores and their grain size distributions, calcium carbonate contents, and oxygen isotope ratios were determined. Here we present characterizations of the interrelationships among the physical and lithologic properties of the sediments in this suite of cores, together with their spatial distributions along the southern Argentine margin and their temporal distributions during the late Quaternary. The expression of these property variations on high-resolution seismic profiles is assessed. Results provide fundamental information about the sediments accumulating along the margin and essential ground-truthing of the geological/environmental significance of high-resolution seismic reflectors. They set the stage for further investigations of how marine geological processes and ocean circulation along the continental margin vary in conjunction with glacial-interglacial fluctuations of climate and sea level.