Australian meteorites
Abstract
Meteorites are an unique source of information about the earliest history of the Solar System. Since the first recorded discovery of a meteorite in 1854 near Cranbourne, Victoria, a total of 277 distinct and authenticated meteorites have been recorded in Australia. The material, including 13 observed falls, comprises 195 stones (ten achondrites, 183 chondrites and two unclassified stones), 68 irons, 13 stony-irons and one meteorite of unknown class. One hundred and forty one meteorites are known from Western Australia, 50 from South Australia, 47 from New South Wales, 14 from Queensland, 11 from the Northern Territory, ten from Victoria and four from Tasmania. A low ratio of falls to finds (1:20) compared with other countries (e.g., USA 1:7) reflects Australias sparse population. However, normalised to population density, the rate of recovery of meteorites (falls + finds) in Australia exceeds that of most other countries of similar size and range of climatic conditions. More than 50% of documented meteorites from Australia have been recovered from Western Australia, 28% coming from the Nullarbor Region including many rare types. Excluding Antarctica, the Nullarbor Region has proved to be one of the most prolific areas in the world for meteorite finds. As in Antarctica, the frequency of meteorite types in the population of meteorites so far collected from the Nullarbor Region is depleted in irons, and may differ from that in the rest of the world. The climatic, physiographic and human factors that contribute to the recovery of meteorites in Australia are examined. Terrestrial ages of meteorites from the arid zone of Australia may help to provide a chronology for recent palaeoclimatic events.
