The bedrock topography of the botany basin, New South Wales

Abstract

Abstract The bedrock topography of the Botany Basin has been determined from seismic‐sparker records made in Botany Bay and Bate Bay, and from seismic‐refraction and gravity measurements on the Kurnell Peninsula. Supplementary information has been obtained from boreholes both on land and in the sea. The Cooks and Georges Rivers formerly constituted the main drainage of the Basin and flowed generally southeastwards (beneath the present Kurnell Peninsula) and joined the Port Hacking River east of Cronulla. The depth of the bedrock channel of the former Georges River is 75–80 m b.s.l. at Taren Point, 90–95 m beneath the Kurnell Peninsula and 110–115 m at its junction with the Port Hacking River channel. The bedrock channel of the former Cooks River is about 30 m b.s.l. at Kyeemagh, its present entrance to Botany Bay, and it joined the Georges River at a location now 90 m b.s.l. beneath the Kurnell Peninsula. A second drainage system existed in the north and east of Botany Bay and generated the present mouth ...