IMCA Insights – November 2009

IMCA Insights – November 2009
The World's Largest Meteorites
by Norbert Classen

The largest meteorites found are usually irons. This is due to the fact that iron meteorites are more stable compared to stony or stony-iron meteorites. The latter two types of meteorites often break up into many pieces upon entering the atmosphere, creating the most impressive phenomenon known as a meteorite shower. Moreover, they suffer from the effects of ablation much more than irons during their passage through the atmosphere. Finally, large iron blocks seem to be much more resistant to the severe effects of terrestrial weathering.

With an estimated mass of over 60 tons the Hoba iron is by far the largest known meteorite (as a single piece). It was found on a farm near Grootfontein in the Otjozondjupa Region of Namibia in the early 20th century, and it still resides at its find location today. It has been declared a National Monument by the Government of Southwest Africa (now Namibia) in 1955.

The 60 ton plus Hoba iron meteorite at its find location in Namibia
(Photo © Gábor Ámon)

The following list shows the top twelve of the largest iron meteorites - the real giants over 10 tons. Please note that this list doesn't display the total known weight of each distinct fall, but rather the weights of the largest individuals that have been recovered from each fall.

Meteorite	Find	Class	Weight°
Hoba	Namibia, 1920	IVB	60.00
Campo del Cielo (El Chaco)	Argentina, 1969	IAB	37.00
Cape York (Ahnighito)	Greenland, 1894	IIIAB	30.87
Armanty	China, 1898	IIIE	28.00
Bacubirito	Mexico, 1863	UNG	22.00
Cape York (Agpalilik)	Greenland, 1963	IIIAB	20.10
Mbosi	Tanzania, 1930	UNG	16.00
Campo del Cielo	Argentina, 2005	IIIAB	14.85
Willamette	USA, 1902	IIIAB	14.14
Chupaderos I	Mexico, 1852	IIIAB	14.11
Mundrabilla I	Australia, 1966	IAB	12.40
Morito	Mexico, 1600	IIIAB	10.10
° weight estimates given in metric tons

The largest known stony-iron meteorite is a relatively new Russian find from 2007, a huge 2.7 ton individual of the Seymchan pallasite. I had the pleasure to see this mass at the Ste. Marie aux Mines Mineral Show, Alsace, France, in 2008 - a real sight to behold.

The 2.7 ton Main Mass of Seymchan at the Ste. Marie Show 2008
(Photo © Hanno Strufe)

The following list shows the top six of the largest stony-iron meteorites, all pallasites. Please note once more that this list doesn't display the total known weight of each distinct fall, but rather the weights of the largest individuals that have been recovered from each fall.

Meteorite	Find	Class	Weight°
Seymchan	Russia, 2007	Pallasite	2.70
Huckitta	Australia, 1937	Pallasite	1.41
Fukang	China, 2000	Pallasite	1.00
Esquel	Argentina, 1951	Pallasite	0.75
Krasnojarsk	Russia, 1749	Pallasite	0.70
Brenham	USA, 2005	Pallasite	0.65
° weight estimates given in metric tons

The final list below shows the top five of the largest stony meteorites, all but one ordinary chondrites and all representing witnessed falls. Please note again that this list doesn't display the total known weight of each distinct fall, but rather the weights of the largest individuals that have been recovered from each fall.

Meteorite	Fell	Class	Weight°
Jilin	China, 1976	H5 Chondrite	1.77
Norton County	USA, 1948	Aubrite	1.07
Long Island*	USA, 1891	L6 Chondrite	0.56
Paragould	USA, 1930	LL5 Chondrite	0.37
Bjurböle*	Finland, 1899	L/LL4 Chondrite	0.33
° weight estimates given in metric tons * these are broken individuals - not preserved

For further reference, much more information, and some great photos of the individual masses of the largest iron meteorites, see a more detailed list of the largest meteorites, compiled by IMCA Member Mike Jensen.