NEW EVIDENCE OF EROSION ON DEEP OCEAN FLOOR

In 1958, the system of deep sea channels in Theta Gap linking the Biscay and Iberian abyssal plains surveyed and their mode of formation was deduced largely from their morphology (Laughton, 1960). In 1960 a further and more detailed study was made of the head of the southern interplain channel, where dredge hauls, cores and bottom photographs were taken. In 1966 the head of the channel was crossed by four seismic reflection profiles. An analysis of the echo-sounding profiles in the detailed survey area showed pronounced benches on the cliffs of the channel, which have been correlated with sub-bottom strata revealed by the seismic profiles, indicating that the channel has been produced by erosion. Further evidence of erosion has come from the photographs on the cliffs which show evidence of slumping, eroded cliffs and steep slopes. © 1968.