Australia: The Land Where Time Began |
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Meteorite Impacts - Astroblemes An origin as a meteorite impact has been ascribed to many of the structures that have been observed around the world, often with lakes in them, that have characteristics such as essentially round craters or depressions, some with raised rims, some with a central rise of various heights. The diameters of such structures range from metres to kilometres. Some, such as the Sikhote Alin impact in Siberia in 1947 was observed falling to earth. A number of minerals associated with high temperature and high pressure, such as coesite, stishovite and iridium are present, as well as structures such as shatter cones, shock lamellae in quartz, glass, breccias, etc. A number of structures that have been determined to be craters of extraterrestrial origin, such as the Henbury Craters, to the southwest of Alice Springs, Northern Territory, Lake Acraman in the Gawler Ranges of South Australia, and the Wolfe Creek Crater in the north of Western Australia. Debris from the Gawler Ranges Volcanic Suite has been found in the Flinders Ranges, having been scattered there as ejecta of the Acraman impact that was deposited in the seas and sediments that formed the Flinders Ranges, about 300 km east of the impact site. Located 26 km south of Queenstown, west central Tasmania, the Darwin Crater lacks the characteristic physiographic features of impact craters, though it is roughly circular, and it is associated with Darwin glass that is believed to have resulted from the heat of impact. Located 160 km west of Alice Springs, Gosses Bluff is one of the best known Australian impact craters.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |