Sediment distribution in the Coral Sea

Analysis of reflection profiles and sonobuoy data from the Coral Sea show that an erosion surface was cut into the Queensland plateau during the Early Tertiary, implying that the Coral Sea basin was in existence at this time. The plateau subsided about 1500 meters during Late Tertiary and Pleistocene times, and a system of normal faults resulted in the formation of the grabenlike trough now separating the plateau from the mainland. The edge of the plateau facing the basin probably was not faulted or seriously deformed at this time. The oldest sediments in the Coral Sea basin are acoustically transparent, predate the erosion surface, and rest directly on basement. They are covered and partly scoured by a thick sequence of turbidites. These older turbidites may be derived from the planation of the Queensland plateau, whereas the younger turbidites are from the Fly River in New Guinea. The Papuan plateau may represent an outer barrier ridge filled to sill depth by Fly River turbidites.