Note on the sediments and hydrology of the Gulf of Carpentaria, Australia

Abstract

The Gulf of Carpentaria is a large embayment less than 70 m deep on Australia's remote northern coastline. This paper, which describes aspects of its hydrology and variation in sediment types, is part of a larger study of the size and distribution of commercial fish resources of the gulf. Much of the data on the hydrology and sediments were collected during a gulf-wide survey in November and December 1990.

Waters in the central part of the gulf were found to be vertically stratified, with bottom temperatures just below 25°C and surface temperatures around 30°C. The waters to the north of the gulf remained well mixed, presumably because of greater tidal mixing through the Torres Strait. In contrast to water temperature, salinity was relatively uniform 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 pm (sandy) in the south-eastern gulf to sediments of > 80% < 63µm (muddy) in the north-west. A second muddy zone was also evident in the coastal zone (<20 m) in sheltered embayments or adjacent to rivers.