World Library  
Flag as Inappropriate
Email this Article

Meteorite fall statistics

Article Id: WHEBN0006043399
Reproduction Date:

Title: Meteorite fall statistics  
Author: World Heritage Encyclopedia
Language: English
Subject: Meteorites, Meteorite falls, Refractory (planetary science), CI1 fossils, Chinguetti meteorite
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Meteorite fall statistics

Meteorite fall statistics are frequently used by planetary scientists to approximate the true flux of meteorites on the Earth. Meteorite falls are those meteorites that are collected soon after being witnessed to fall, whereas meteorite finds are discovered at a later time. Although there are 30x more finds than falls, their raw distribution of types does not accurately reflect what falls to Earth. The reasons for this include:

  1. Some meteorite types are easier to find than others
  2. Some meteorite types are degraded by weathering more quickly than others
  3. Some meteorites, especially iron meteorites, may have been collected by people in the past who recognized them as being unusual and/or useful, thereby removing them from the scientific record
  4. Many meteorites fall as showers of many stones, but when they are collected long after the event it may be difficult to tell which ones were part of the same fall
  5. Many meteorites are found by people who sell meteorites... valuable, rare types become known to science quickly, while those of low value may never be described.

There have been many attempts to correct statistical analyses of meteorite finds for some of these effects, especially to estimate the frequency with which rare meteorite types fall. For example, there are over 100 known lunar meteorite finds, but none has ever been observed to fall. However, for abundant types, meteorite fall statistics are generally preferred.

These statistics are current through June 9, 2012.

Statistics by material

For most meteorite falls, even those that occurred long ago or for which material has never received complete scientific characterization, it is known whether the object was a stone, stony iron, or iron meteorite. Here are the numbers and percentages of each type, based on literature data.[1][2][3]

Material Number %
Iron meteorites 49 4.4%
Stony-iron meteorites 11 1.0%
Stony meteorites 1042 94.6%
Total 1102 100.0%

Statistics by major category

The traditional way of subdividing meteorites (see Meteorites classification) is into irons, stony-irons, and two major groups of stony meteorites, chondrites and achondrites. For some of the less-studied stony meteorite falls, it is not known whether the object is chondritic; thus the number of meteorites that can be so grouped is 4% lower than shown above. These numbers are shown in the next table. One could make a slight correction for the undercounting of stony meteorites (e.g., the percentage of irons would decrease by a 0.2%), but this was not done.

Category Number %
Irons 49 4.6%
Stony irons 11 1.0%
Achondrites 86 8.2%
Chondrites 915 86.2%
Total 1062 100.0%

Statistics by meteorite group

Probably the most useful statistical breakdown of meteorite falls is by group, which is the fundamental way that meteorites are classified. About 5% of the meteorites in the table just above have not been sufficiently classified to allow them to be put into such groups. Again, a small adjustment could be made to the percentages to correct for this effect, but it does not greatly change the results. Note that a number of meteorite groups are only represented by a small number of falls; the percentages of falls belonging to these groups have a large uncertainty.

Group N %
Iron meteorites
IAB complex 10 1.0%
IC 0 0.0%
IIAB 6 0.6%
IIC 0 0.0%
IID 3 0.3%
IIE 2 0.2%
IIF 1 0.1%
IIG 0 0.0%
IIIAB 11 1.1%
IIIE 0 0.0%
IIIF 0 0.0%
IVA 4 0.4%
IVB 0 0.0%
Ungrouped 4 0.4%
Stony Iron meteorites
Mesosiderite 7 0.7%
Pallasite 4 0.4%
Group N %
Achondrites
Acapulcoite 1 0.1%
Lodranite 1 0.1%
Angrite 1 0.1%
Aubrite 9 0.9%
Diogenite 11 1.2%
Eucrite 34 3.4%
Howardite 16 1.6%
Brachinite 0 0.0%
Ureilite 6 0.6%
Winonaite 1 0.1%
Ungrouped 2 0.2%
Lunar 0 0.0%
Martian 5 0.5%
Group N % Class total
Chondrites
CB 1 0.1% Carbonaceous:
4.4%
CH 0 0.0%
CI 5 0.5%
CK 2 0.2%
CM 15 1.5%
CO 6 0.6%
CR 2 0.2%
CV 7 0.7%
C ungrouped 6 0.6%
EH 8 0.8% Enstatite:
1.6%
EL 8 0.8%
H 339 33.8% Ordinary:
80.0%
H/L 1 0.1%
L 371 37.0%
L/LL 9 0.9%
LL 82 8.2%
R 1 0.1% Other:
0.2%
K 1 0.1%
Grand Total: 1003 meteorites

Statistics by country

Country N
Afghanistan 1
Algeria 7
Angola 3
Argentina 24
Armenia 2
Australia 16
Austria 4
Azerbaijan 2
Bangladesh 8
Belarus 3
Belgium 3
Bosnia and Herzegovina 1
Brazil 22
Bulgaria 6
Burkina Faso 8
Burma 3
Cambodia 2
Cameroon 3
Canada 16
Central African Republic 1
Chad 1
Chile 1
China 58
Colombia 1
Congo - Dem. Rep. 5
Costa Rica 1
Croatia 4
Country N
Czech Republic 15
Denmark 4
Ecuador 1
Egypt 2
Estonia 3
Ethiopia 5
Finland 5
France 63
Germany 32
Ghana 1
Greece 1
Hungary 6
India 127
Indonesia 16
Iran 2
Iraq 2
Ireland 6
Italy 31
Japan 42
Jordan 1
Kazakhstan 6
Kenya 4
Latvia 4
Lebanon 1
Lesotho 1
Libya 1
Lithuania 4
Madagascar 1
Country N
Malawi 5
Mali 2
Mauritania 3
Mauritius 1
Mexico 19
Mongolia 4
Morocco 6
Namibia 2
Netherlands 4
New Caledonia 1
New Zealand 1
Niger 9
Nigeria 14
Norway 9
Pakistan 15
Papua New Guinea 2
Paraguay 1
Peru 1
Philippines 4
Poland 11
Portugal 6
Romania 7
Russia 47
Rwanda 1
Saudi Arabia 4
Serbia 4
Slovakia 3
Country N
Slovenia 2
Somalia 2
South Africa 21
South Korea 3
South Sudan 3
Spain 23
Sri Lanka 1
Sudan 7
Swaziland 1
Sweden 9
Switzerland 4
Syria 1
Tanzania 8
Thailand 3
Tunisia 5
Turkey 12
Turkmenistan 2
Uganda 5
Ukraine 32
United Kingdom 18
United States 146
Uzbekistan 2
Venezuela 2
Vietnam 3
Western Sahara 3
Yemen 2
Zambia 1
Zimbabwe 2
Grand Total: 1103 meteorites

Statistics by continent and time

Epoch Europe Asia North
America
Africa South
America
Oceania Total
Pre-1400 1 1 2
15th century 4 4
16th century 2 2
17th century 9 3 12
18th century 25 3 28
1800–1820 31 7 3 1 42
1821–1840 26 11 9 1 1 48
1841–1860 42 15 12 1 70
1861–1880 47 36 14 6 4 1 108
1881–1900 36 27 20 7 2 92
1901–1920 27 55 21 10 4 2 119
1921–1940 38 55 32 17 14 5 161
1941–1960 27 27 18 31 12 3 118
1961–1980 19 42 22 29 8 3 123
1981–2000 12 49 19 24 4 2 110
2001- 11 15 12 16 7 2 63
Total 357 346 121 144 53 20 1102

See also

References

  1. ^ Meteoritical Bulletin Database
  2. ^ The NHM Catalogue of Meteorites
  3. ^ MetBase
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.