Meteorites Rare In New Zealand

Press, Volume CVIII, Issue 31802, 5 October 1968, Page 5

Meteorites Rare In New Zealand

‘Contributed by the Canterbury Museum)

Rumours of meteorites are common, but actual specimens are rare, and only five meteorites have been recorded from New Zealand.

In these days of space research meteorites are being studied intensively because these missiles from outer space are, as yet, the only samples of the solar system from beyond the earth that can be handled and studied like ordinary rocks. There are two main types of meteorites: the iron meteorites or “irons” consisting mainly of nickel-iron alloys; and the stony meteorites or “stones” consisting largely of silicate minerals and not very different in composition from volcanic rocks on earth. Stony meteorites are thought to be about ten times more common than irons: but irons are more common in museums as they are easily recognised as meteorites. Irons are rarer in Europe, Asia and Africa where the working of iron has been known since prehistoric times and many iron meteorites must have been converted into weapons and tools. Occasionally meteorites are seen to fall. It has been estimated that about 500 hit the earth each year, but since over 70 per cent of the surface is covered by water some 350 of these will probably fall in the sea. The recovery of meteorites is very slow. In the years between 1800 and 1960 about 670

meteorites which were seen to fall have been collected—an average of only 4 per year. New Zealanders are a bit better than average in finding meteorites. About 1700 meteorites have been found in the world—3o for every million square miles of land. New Zealand's total of 5 is a score of about 50 per million square miles. The French and Germans appear to be champions with scores of about 280 per million square miles, whereas the Chinese have the very poor score of less than two meteorites per million square miles. One meteorite has been recovered after having been seen to fall in New Zealand. At 12.30 p.m. on November 26, 1908, people living at Mokoia, a small wayside station near Hawera, were startled by a series of loud explosions like a volley of rifle shots.

Those outside saw a bright flash shoot across the sky leaving a thin white cloud. A fir tree was found to have been splintered and at the foot of 'the tree, in an Ilin crater, were found two darkcoloured stony fragments weighing together lOjlb. This Mokoia meteorite, which was presented to the Wanganui Museum, is unusual in that it contains compounds of carbon and hydrogen.

Closelv Studied

Over the last few years It has been closely studied, along with the other 24 carbonaceous meteorites known, as some scientists suspect that the hydrocarbons may be derived from some sort of extra-terrestrial life.

Of the other New Zealand meteorites one was found about 1863 near Masterton, one near Invercargill in 1879. and another at Morven in South Canterbury in 1925. The latest find was brought to the Canterbury Museum in 1954 by Mr L. F. Blatcn: it had been found about 1952 at View Hill, near Oxford, by Mr C. C. Anderson. This 741 b rust-covered ; meteorite is the only “iron' known from New Zealand. It was studied by Dr Michael Frost, formerly of the University of Canterbury but now at the British Museum (Natural History), and whose report was published in the "Museum Records” last year. He found that the meteorite contained 8.2 per cent nickel and a cut and polished surface, etched with acid, clearly showed the characteristic criss-cross Widmanstatten pattern produced by crystals of nickel-iron alloys. On Display This meteorite is now on display in the Von Haast Hall of Geology at the Canterbury Museum. Rumours of meteorites are common; it Is seldom that specimens brought to a museum prove to be genuine meteorites. Furnace slag, fragments of cast iron, or natural concretions of various sorts are sometimes mistaken for meteorites. But, in a hope that a sixth New Zealand meteorite will be found before long, specimens thought to be meteorites will always be welcomed lat the museum.—D.R.G.