NOTE ON THE SEDIMENTS AND HYDROLOGY OF GULF OF CARPENTARIA, AUSTRALIA

The Gulf of Carpentaria is a large embayment less than 70 m deep on Au stralia's remote northern coastline. This paper, which describes aspec ts of its hydrology and variation in sediment types, is part of a larg er study of the size and distribution of commercial fish resources of the gulf. Much of the data on the hydrology and sediments were collect ed during a gulf-wide survey in November and December 1990. Waters in the central part of the gulf were found to be vertically stratified, w ith bottom temperatures just below 25-degrees-C and surface temperatur es around 30-degrees-C. The waters to the north of the gulf remained w ell mixed, presumably because of greater tidal mixing through the Torr es Strait. In contrast to water temperature, salinity was relatively u niform throughout the water column: between 35 and 36. In depths below 20 m, there was a clear trend in sediment grain size, from sediments of >80% >63 mum (sandy) in the south-eastern gulf to sediments of >80% <63 mum (muddy) in the north-west. A second muddy zone was also evide nt in the coastal zone (<20 m) in sheltered embayments or adjacent to rivers.