THE EQUATORIAL ATLANTIC MIDOCEAN CHANNEL - AN ULTRA-HIGH-RESOLUTION IMAGE OF ITS BURIAL HISTORY BASED ON TOPAS PROFILES

Multibeam bathymetric and ultra high-resolution seismic data reveal th at the distal course of the Equatorial Atlantic Mid-Ocean Channel (EAM OC) extends further east and south than was previously known, and is c ontrolled by the presence of morphologic highs related to the Fernando de Noronha Fracture Zone. The distal course of the EAMOC is buried by sediments, and does not have bathymetric expression on the seafloor. The channel fill consists of three seismic sequences, suggesting that the recent geological evolution of the channel is composed of successi ve phases of decreasing sedimentary activity that finally resulted in its complete burial. Tectonic and volcanic activity related to the Fer nando de Noronha Fracture Zone and Ridge, together with the effect of strong pulses of the Antarctic bottom water current during the upper P liocene are suggested to have contributed to the progressive burial an d the final abandonment of the EAMOC.