Wednesday, 24 June 2009

Cranbourne Meteorites

The first meteorite discovered in the Cranbourne region was in 1853. The first time they came to the public notice was in 1854 at the Melbourne Exhibition when a horseshoe was exhibited made from a specimen of iron from Western Port. This iron turned out to have come from the Cranbourne No. 1 meteorite. Another crop of iron (Cranbourne No.2) had also been discovered 6km from the first however it wasn’t until 1860 that the two outcrops of ‘iron’ were identified as meteorites. This publicity bought to life another meteorite which had been unearthed in 1857. This meteorite is known as Cranbourne No. 3. These meteorite discoveries created interest overseas partly due to their size, and were reported in scientific papers.

We will look at the meteorites in detail. Cranbourne No. 1, weighs 3,550kg is now housed at the National History Museum in London. It has been in England since 1865 when it was acquired by the British Museum. It was found around Craigs Road in Devon Meadows.

Cranbourne No.1 or No.2, being unearthed in 1862. Photographs by Richard Daintree, held at the State Library of Victoria.

Cranbourne No. 2 weighs 1,525 kg and is at the Melbourne Museum, though it was initially purchased by the British Museum for £300 in 1862. Colonial scientists strongly protested at the loss to England of both these meteorites and so Cranbourne No.2 was returned to Melbourne. It had been discovered in Clyde at the property owned by James and Charlotte Lineham. In an article (reproduced below) in the Pakenham Gazette on October 3rd 2001, there was an interview with two great grandchildren of James and Charlotte, Glenda Tait and Jean Hermon, who remembered stories their grandmother Susanah Beazley (nee Lineham) told of the meteorite Grandma said the meteor was worshipped by the Aborigines who came to the property and that it was special to them and they cried when they saw it being taken away.

Cranbourne No.3 was discovered in 1857 and was 6.8kg. It was found on the same farm as Cranbourne No.1 and had been broken in two, one part being used as a kitchen hob. Unfortunately both pieces are now lost. Cranbourne No.4 is 1270 kgs and Cranbourne No.5 weighs 356 kg. They are both at the Melbourne Museum and were both unearthed in separate locations in 1923 in the Devon Meadows area between Browns Road and North Road.

Cranbourne No.6 was discovered in Pakenham, west of the Toomuc Creek, during works connected to the widening of the Princes Highway, in 1928 and weighs 40.5 kg. Numbers 7 & 8 were both discovered in 1923, in the same paddock as No.5 and weigh 153 kg and 23.6 kgs respectively. Numbers 4, 5, 6 and 8 are at the Melbourne Museum and no.7 is at the University of Melbourne.

No.9 was discovered in 1876 in a railway cutting about three kilometres east of the Beaconsfield Railway station and weighs 75 kg. It was broken up into samples which are now at various Institutions around the world. Cranbourne No.10 was found at Langwarrin in 1886, by a farmer ploughing his field. No.11 was discovered two kilometres north of Pearcedale in 1903. No.10 is 914 kg in weight and is at the Melbourne Museum and No. 11 is at the National Museum in Washington, and weighs 762 kg.

Number 12 was also found in Pearcedale, in 1927 though it was not identified as a meteorite until 1982. This 23 kg piece is on display at the City of Casey Civic Centre at Narre Warren. The last and thirteenth meteorite was found on a market garden at Clyde, and weighs 85 kg. The farmer had being working around this rock for years, but it was only dug up and identified as a meteorite in 2008. Though he could have sold it for a large sum of money, he generously donated it to the Melbourne Museum and it is now on display at the Casey RACE Leisure Centre at Cranbourne.

This map, showing the locations of the Meteorite finds, is reproduced from a tourist brochure produced by the Shire of Cranbourne to promote their Meteorite display on the South Gippsland Highway in Cranbourne. Click on image to enlarge it.

Most of these meteorites were discovered by chance, mostly by farmers ploughing their paddocks. The Meteorites were all located in a straight line, except for the slight deviations of No.6 and No.11, and are 21 kilometres apart (see map above). There are no large craters, such as the one at Wolfe Creek in Western Australia, as the Cranbourne Meteorites impacted at a low angle on swampy or sandy ground. Our meteorites are iron of the Octahedrite type, the most common type of iron meteorite and are some of the heaviest in the world. For more scientific information on the Meteorites follow this link to the City of Casey website. They have reproduced a report from the 1982 Australian Gem and Treasure Hunter Yearbook by William Cappadonna. I also googled “Cranbourne meteorites” and came across an interesting report (citation below) where the Cranbourne No.1 meteorite was used to test the theory that there was water on the moon. The actual experiment involved comparing the akaganeite which formed on the meteorite to akaganeite taken from rocks collected by Apollo 16 from the moon. The Cranbourne Meteorites are of international importance and I wonder how many other meteorites may still lie undiscovered in our area?

The article referred to is Experiments on the stability of FeOOH on the surface of the moon by Lawrence A. Taylor and Jacqueline C. Burton. Published in Meteoritics, v.11, no.3, September 30 1976.

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