Located approximately 130 kilometres south of Alice Springs, in Australia's Northern Territory Outback, lay a collection of 12 craters scattered over an area of about one square kilometre. The craters range in size - anything from 6 to 146 meters in diameter, and were created by the impact of a meteorite upon the earth's crust many millennia ago. It is a very impressive sight.
Although the craters had been known of by the local residents for a great many years, they were not truly explored until May 1931, when R.A. Alderman and his assistant, Bedford organised several small parties of scientific researchers to examine the craters and recover any traces of materials remaining from the meteorites. Large quantities of the meteor's fragments were removed from the area, and over the years, especially since the Henbury Craters became a tourist attraction, the site has been almost completely stripped of fragments. As a result of this, the Australian Government has closed most of the area - and the collecting of any fragments by non-authorised persons is strictly prohibited.
Native Australian legend says that the craters were formed during a 'fiery explosion', and the site is known to the Aboriginal people as 'Chindu chinna waru chingi yabu', or 'Sun walk fire devil rock'. When taking into consideration the history and age of the native Australian race, it is quite possible that Henbury was a witnessed fall.
Through scientific research, it is said that the meteorite 'weighed several tonnes and, accelerating to over 40,000km per hour, disintegrated before impact, hence the number of craters formed by the fragments'. The fragments are extremely heavy and consist mainly of the metals iron (90%) and nickel (8%). Over 1200 kilograms of iron meteorite fragments have so far been recovered from the site and surrounding areas - the largest salvaged piece weighed it at over 100 kilograms.
In 1922, the Henbury craters were among the first in Australia to be recognised as being of impact origin. Studied extensively in the 1960's by the United States Geological Survey as a training area for the Apollo program, they now have the title of being Australia's most studied impact craters.
Access to the craters is via a '4WD track' from Stuart Highway, and although the site is now a conservation reserve, the area is so remote and infrequently visited, that the Nothern Territory Tourist Board advise;
'......4WD Track: Rate medium-good. Area: Remote not frequently visited. Any geological research will need permission from the National Parks and Wildlife Service in the Northern Territory. Aboriginal Heritage issues may also need to be considered. Work: All work in the area must have adequate communications facilities and emergency procedures in place. Safety: Two vehicles in the party is advisable. Water is probably the main survival issue. Nearest medical facility is Alice Springs. Overall: Risk is medium.'
For the many people that enjoy geology, the information that I have researched quotes;
'The geology is of great interest, although well studied. The bedrock consists of weathered, gently dipping Neoproterozoic shales and thin sandstones covered by a veneer of pediment gravels. Formation of the crater rims during impact is well exposed. Craters 3 and 4 have attracted particular interest, as they are the only terrestrial craters to show analogues to lunar rays in their ejecta patterns. The main unknown features of the geology are the timing of the impact, although more accurate dating using thermoluminescence and cosmogenic isotopes is a distinct possibility. Detailed regolith mapping also has not been carried out.'
http://www.marssociety.org.au/jnt-db/Australia-NT_S-Henbury.html
http://www.s-d-g.freeserve.co.uk/craters.html
http://www.abc.net.au/science/k2/trek/4wd/Over11.htm
http://www.flash.net/~meteors/Henbury.htm