Henbury (meteorite)
Coordinates: 24 ° 34 ′ 22.9 ″ S , 133 ° 8 ′ 52.3 ″ E
Henbury is a group of twelve confirmed and several unconfirmed meteorite impact structures located approximately 120 kilometers southwest of Alice Springs in the Northern Territory , Australia . The largest of the Henbury craters is 157 meters in diameter. The arrangement of the impact structures and the distribution of the meteorite fragments along a 6 km long axis indicate a successive fragmentation of the meteoroid along its trajectory until shortly before the impact of the main crater-forming masses.
Discovery and early exploration
The time of the impact of a medium-sized iron meteorite ( middle octahedrite , group IIIAB) is dated 4200 ± 1900 years ago , i.e. in the Holocene . The crater field was first mentioned in 1899 in the correspondence of the founder of the Henbury Cattle Station, Walter Parke, with the well-known anthropologist Frank J. Gillen. The first scientific description was in 1931 by Professor Arthur Alderman of Adelaide University. In Alderman's report, radial ejection structures were described for the first time, as they were previously only known from impact structures on the moon. In 1931 and 1932 two expeditions followed under the direction of Robert Bedford from Kyancutta. During the first expedition around 200 kg of meteorite fragments were recovered. The majority of these were shrapnel , i.e. H. Fragments of the masses destroyed during the impact and ejected from the craters. In 1932 Bedford excavated the smaller impact craters. In crater no. 13, which is called "Discovery Crater" in later publications, Bedford found several heavily corroded iron masses with a total weight of ~ 200 kg at a depth of around two meters. In addition, Bedford discovered a stray field from further meteorite fragments that extended 1 to 5 km northeast of the actual crater field. These were not impact shrapnel, but meteorites with clear ablation features, i.e. H. individual flight history. A total of ~ 1350 individual masses were recovered by Alderman and Bedford, of which Bedford's share was a little over 425 kg. Bedford later sent much of his records and finds to the British Museum in London.
Determination of the flight direction
While research in the subsequent period was almost exclusively based on the position and arrangement of the impact structures in the reconstruction of the impact, the position and orientation of the ejection material, but above all the distribution of the meteorite fragments, remained almost unnoticed. The flight direction of the Henbury Boliden was therefore given solely on the basis of the size distribution of the individual structures in the crater field until the 1990s with west-south-west to east-north-east. Today we know that this theory can be ruled out due to the main direction of the crater shrapnel being ejected to the west and south-west. The scattered field documented by Bedford in 1932 and by McColl in 1997 with hundreds of smaller individual masses with individual ablation history in the northeast of the impact structures also contradicts this theory. It was not until 2012 that Buhl & McColl was able to provide clear evidence of the flight direction of the Henbury Boliden from east-north-east to west-south-west, taking into account all available data.
Cultural meaning
According to reports from prospector JM Mitchell, this formation is called Chindu chinna waru chingi yaku in Aboriginal culture , which translates as "sun goes fire devil's rock" - this would be an indication that the fall and explosion of the meteorite was observed. However, according to Alderman and Bedford, the origin of the Henbury crater structures is unknown to local Aboriginal tribes. In the center of the crater field is now an Aboriginal sanctuary recognized by the administration of the Henbury Conservation Reserve. The Australian anthropologist Duane W. Hamacher points in this context to a taboo of the tribal elders, which forbids them from sharing the legends associated with the Aboriginal shrines with Europeans.
Tourist development
Since the craters collect the rare rain in the outback from time to time , they also serve as an important source of water. The main craters have been protected as a nature reserve since 1934. Today's Henbury Meteorites Conservation Reserve has existed since 1983 and, in addition to the 12 impact structures, also includes most of the meteorite stray field in the northeast of the crater. Despite their short distance from the well-known Uluṟu, by Australian standards, the craters were of little tourist relevance for many years, as they are off the usual tourist routes in the outback and can only be reached via the unpaved Ernest Giles Road . The flow of visitors is now growing, with over 25,000 tourists visiting the place every year.
See also
credentials
- ↑ Archive link ( Memento from September 27, 2007 in the Internet Archive )
literature
- Arthur R. Alderman: The meteorite craters at Henbury . In: Nature no. 3240, vol. 128, December 5, 1931.
- Arthur R. Alderman: The meteorite Craters at Henbury, Central Australia . In: Mineralogical Magazine, vol. 23 (March), London 1932.
- Robert Bedford: Surface markings of the Henbury meteorites . In: Nature, vol. 133, April 14, 1934.
- Paul W. Hodge: The Henbury meteorite craters . In: Smithsonian Contributions to Astrophysics, vol. 8, no.8, Washington 1965.
- Svend Buhl, Don McColl: Henbury Craters & Meteorites - Their Discovery, History and Study . Edited by S. Buhl, Meteorite Recon, Hamburg 2012, ISBN 978-3-00-039026-5
