Southern Australian submarine canyons: Their distribution and ages

Abstract

A study of available echo sounding data, coupled with a recent Precision Depth Recorder section along the continental slope, has enabled detailed plotting of submarine canyon axes along the continental margin of southern Australia. Groups of large submarine canyons are confined to the continental slope in areas of shallow basement rock, opposite on-shore areas of Cambrian to Precambrian rocks. Areas of Tertiary basin development, both on-shore and on the continental shelf, lack a development of major submarine canyons on adjacent continental slopes. Relics of Early Tertiary or pre-Tertiary large-scale drainage systems on the ancient land surface of the Great Plateau, of southwestern Australia, may be related to the large submarine canyons. Results of the study indicate at least an Early Tertiary age for initial sub-aereal cutting of heads of the large canyons. Smaller canyons, occurring on slope areas in the vicinity of Tertiary basins, may be related to Pleistocene low sea level stands.