We investigate an extensive (> 11000 km) set of high quality seismic reflection profiles from the Argentine continental margin. The profiles show a significant contourite system formed by the interaction of northward flowing Antarctic water masses and southward flowing North Atlantic Deep Water (NADW). Here we present preliminary results from the southern part of the continental margin (42o-50o S) where we focus on a set of 50 km wide terraces on the slope and rise separated by contouritic channels. An initial age frame was developed by mapping regional reflectors and seismic units known from previous studies. The sedimentary layer between regional reflectors AR 4 and AR 5 spanning roughly the time interval from the Eocene/Oligocene boundary to the early middle Miocene thickens towards the East forming a giant buried drift and also towards the West building plastered drifts below the Piedra Buena Terrace. In contrast to this the sediments of late Miocene to recent age are very thin or completely eroded over the Piedra Buena terrace but form drifts at the Valentin Feilberg terrace that can be divided into subunits whose reflections show good lateral continuity. With an age of 15 Ma for reflector AR5 the average sedimentation rate since the middle Miocene is estimated to be > 10 cm/ka.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 3: Lessons from the Past > WP 3.2: Tectonic, Climate and Biosphere Development from Greenhouse to Icehouse