SANDS OF THE SYDNEY BASIN

Unlike the quartz-lithic sediments of the Terrigal Formation that came from the New England Fold Belt, Hawkesbury Sandstone contains much more quartz-rich sediment. It is a much more massive sandstone formation than the lower (earlier) Terrigal Formation. It was previously assumed that the sediments came from the Lachlan Fold belt to te south-west, but it has been hypothesised that the Hawkesbury Sandstone sediments may have been deposited by a very large river originating in Antarctica when Australia was closer to the south pole. Due to the arrangement of the continents, the same sediment may have been deposited in Western Australia and India. Hawkesbury sandstone can be found in the Sydney region, the Bouddi Peninsula and west of Brisbane Water, but it has been eroded away further north.