SEDIMENT LOADS IN AN AUSTRALIAN DUST STORM - IMPLICATIONS FOR PRESENT AND PAST DUST PROCESSES

On 1 December 1987 a dust storm driven by a strong cold front entrained soil from 100,000 to 200,000 km(2) of the Simpson Desert, Channel Country and semi-arid woodlands of Western Queensland for eighteen hours. Between 6.3 and 5.5 million t of soil with average particle sizes of 6.75 to 10.5 mu m, were lost from the dust source, 3.4 to 1.9 million t was lost off the Australian continent, and from this some 3 to 1.7 million t might have traversed the Tasman sea towards New Zealand. A mathematical model is used to estimate dust lost from the region. This approach provides estimates of Total Suspended Particulate (TSP) that are within a factor of 3 of observations. From statistics of the frequencies of dust storms 3.8 to 6.8 million t of dust per year is estimated to fall into the South Pacific and contribute to marine sediments. These are the largest estimates of soil loss by wind in Australia and support quantitatively earlier hypotheses of the significance of dust processes in the evolution of the Australian landscape.