A possible giant multiringed impact crater off the Patagonian coast

JULIO GRATTON

Tandil

Congreso; AFA 2014; 2014

Asociación Física Argentina

The Permian-Triassic (P-T) transition occurred some 252 My ago and is associated with the largest known extinction in which 95% of marine species disappeared. Its cause is still a motive of controversy. Several researches have suggested that it was a consequence of the eruption of the Siberian Traps (ST) that occurred at approximately the same time. On the other hand many authors believe it is due to a giant impact. The Bedout structure near Australia has been suggested as a possible candidate. However the evidence is scarce and the size of this structure in not sufficiently large to justify magnitude of the P-T extinction. The Araguainha crater in Brazil is of the adequate age but its size ( 40 km) is obviously too small. No important Ir anomaly is associated to the P-T transition, but this does not rule out the impact of a stony or a cometary body. We shall discuss the possibility of a giant impact off the Patagonian coast that produced a multiringed structure some 1200 km in diameter, that is of the right size and age to produce the P-T extinction.