In February-March 2007 PMGE, VNIIOkeangeologia and AWI conducted a joint geophysical survey in the area between the Prydz Bay and the southern Kerguelen Plateau (SKP) using two research vessels. Totally 5 000 km of MCS, gravity and magnetic profiles, 37 OBS records (along two N-S oriented MCS lines) and about 8000 km of detailed helicopter magnetic lines (in two local corridors centered on MCS-OBS profiles) have been acquired. Additionally two-ship (long-aperture) seismic experiment has been carried out along the 72.7E MCS-OBS line. Conducted investigations enabled definition crustal characteristics of this region, mapping principal tectonic provinces and features and development a seismic stratigraphy model. Major preliminary outcomes of the study are following: 1) the COB off Prydz Bay is marked by emplacements of mantle rocks into the lower crust (incomplete mantle unroofing) and is located 20-70 km southward of the prominent linear magnetic anomaly (Mac. Robertson Coast Anomaly); this anomaly might reflect a more active melt production during initial emplacement of the Kerguelen Plume into the oceanic lithosphere; 2) oceanic crust between 68E and 76E shows symmetric consequences of M-series magnetic anomalies with proposed extinct spreading centers implying paleoridge jumps; the SKP was probably isolated from India margin during this event and is underlain by extended continental crust; 3) flat-lying terrace with thickened (10-11 km) magmatic crust was recognized around the major morphological elevation of the SKP.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > MAR2-Palaeo Climate Mechanisms and Variability