Meteorites and Their Properties

V. Frequency of Falls

Most meteorites that have fallen to the Earth (~93%) are chondrites or achondrites (stony meteorites). A smaller fraction of them are iron meteorites (~6%), or pallasites and mesosiderites (stony-iron meteorites; ~1%) (4).

A statistical study of the rates of meteorite falls (5) suggests approximately 17 meteorites >0.1 kilograms (0.22 pounds) in size fall in Arizona, or an area of equal size, each year. Two to three of these samples weigh >1 kilograms (2.2 pounds) and are about the size of your fist. A meteorite weighing >10 kilograms (22 pounds) falls every 2 to 3 years. Thus, from the turn of the century, approximately 240 meteorites >1 kilograms in size are believed to have fallen in Arizona. Since Father Kino first arrived in the Tucson area (1687), approximately 790 meteorites >1 kilograms in size are believed to have fallen in Arizona. Of this large number of meteorites, only 32 have been recovered, and only 1 of these (the Holbrook meteorite) was observed to fall (2).

In comparison, 153 meteorites have been found in New Mexico, 3 of which were observed falling. Seventy of these samples were collected within Roosevelt County, where a special set of circumstances has preserved and concentrated a large number of meteorites.

It should be clear from these numbers that most meteorites that fall are not found, and very few are actually observed hitting the ground. Thus, there are many meteorites in Arizona waiting for some curious soul to take notice.

List of Arizona Meteorites

County Type of
and Year

Bagdad Mohave Iron Found 1959
Canyon Diablo Coconino Iron Found 1891
Cat Mountain Pima OC Found 1980-82
Cave Creek Santa Cruz OC Found 1992
Clover Springs Gila MES Found 1954
Coon Butte Coconino OC Found 1905
Cottonwood Yavapai OC Found 1955
El Mirage Maricopa Iron Found 1972
Gold Basin Mohave OC Found 1995
Greaterville Pima OC Found 1995
Gun Creek Gila Iron Found 1909
Hassayampa Maricopa OC Found 1963
Hickiwan Pima OC Found 1974
Holbrook Navajo OC Fell 1912
Kofa Yuma Iron Found 1893
Maricopa Maricopa OC Found 1980
Navajo Apache Iron Found 1921
Pima County Pima Iron Found 1947
Ryan Field Pima OC Found 1982
San Francisco Mtns Coconino? Iron Found ~1920
Seligman Coconino Iron Found 1949
Silver Bell Pima Iron Found 1939
Southern Arizona ? Iron Found 1947
Snyder Hill Pima OC Found 1994
Tucson Pima? Iron Found 1850
Udall Park Pima OC Found 1985
Wallapai Mohave Iron Found 1927
Weaver Mtns Maricopa Iron Found 1898
Wickenburg Maricopa OC Found 1940
Wikieup Mohave OC Found 1965
Willcox Playa Cochise OC Found 1979
Winona Coconino AC Found 1928

* CC = carbonaceous chondrite, OC = ordinary chondrite, EC = enstatite chondrite, MES = mesosiderite, AC = unusual achondrite.
Found sometime before this year
Rediscovered in a prehistoric stone cist in 1928

(4) Harvey and Cassidy (1989) Meteoritics, v. 24, pp. 9-14.

(5) Halliday and others (1989) Meteoritics, v. 24, pp. 173-178.

Next: The appearance of a freshly-fallen meteorite [En Español]

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