Crustal structure across the Tasman Sea

Abstract

Abstract A crustal section across the Tasman Sea between latitudes 31° S and 35° S has been obtained by interpreting continuous gravity measurements with the aid of previous seismic measurements. A quasi‐continental type of crust exists under the Dampier Ridge (crustal thickness 20 km), Lord Howe Rise (26 km), West Norfolk Ridge (21 km), and Norfolk Ridge (21 km). The crust beneath the New Caledonia Basin is of oceanic type (9 km). Short wavelength gravity and magnetic anomalies over Lord Howe Rise, West Norfolk Ridge, and Norfolk Ridge suggest that dense, magnetic, intrusive rocks occur within or beneath a thin (< 1 km) sediment cover. The thickness of the sediments in the centre of the New Caledonia Basin is about 1 km and increases to about 2 km at the foot of the Lord Howe Rise and about 3 km at the foot of the West Norfolk Ridge.