The sedimentary framework of Moreton Bay, Queensland

Abstract

Moreton Bay occupies an area of 540 sq miles on the south-east Queensland shelf, and is bordered on the east by high barrier islands. It is divisible into a deep northern sector and a narrower southern region in which numerous small sand islands occur. Unusually vigorous tidal activity has resulted in tidal deltas and sand ridges on the northern and eastern margins. The main sedimentary pattern in the Bay has been determined by the Mesozoic and Cainozoic history of the region, particularly the tectonic and eustatic variation. At the present time, the main sediment source is from the shelf and barrier islands where ancient dune deposits are "feeding" the Bay. The main contribution from the western land mass is mud, which is largely restricted to the western part of the Bay. Relict coral reefs and existing coral communities contribute to a carbonate facies which is very restricted in distribution. The main movement of sediment is by tidal currents which are most effective on the eastern side of the Bay where the sediment is predominantly quartz sand.