Meteorites with clasts of more than one type ofĪlteration are designated with the range of alteration The initial letter designation for ordinaryĬhondrites, "O", is usually deleted. Most common meteorite from observed falls-73.5%. Plagioclase, and occasional olivine (EH). H indicates high metallic ironĪnd L indicates low metallic iron. Here is a diagram from Weisberg showing petrologic types for each group:Į stands for Enstatite. Impact melting is notĬonsidered a proper basis for type 7 classification.įuture research is expected to clear up this issue. Previously described as type 7 are either type 6 or are impact melts. No firm agreement among meteorite researchers on theĭefinition of type 7 chondrites. Here is a table from Weisberg indicating the criteria for petrologic type" Chondrites of Petrologic Type 3 are referred to as "unequibrated" because of their lack of metamorphism. A lack of numericĭesignation means that no alteration designation has beenĪssigned. Aĭesignation of 1 indicates that chondrules have been Three indicate increasing aqueous alteration. A designation of 7 indicatesĬomplete obliteration of chondrules. Numbers greater than 3 indicate increasing Number refers to the alteration of the chondrules. 82 percent ofĬlassified chondrites are given a number designation to catagorized their "petrologic type." The To link to an article on the Nature and Origin ofĬlose-up picture of chondrules. Chondrites are believed to be among the oldest
MeteoriteĬatalogs and information pages for specific meteorites.)ĭistinguishing Features/ Chondrule Characterĭiameter of 1 mm) of formerly melted minerals that haveĬome together with other mineral matter to form a solid On a mineral name you will be linked to the Meteorite Mineral Pictures of meteorites or to explanatory material. Harry McSween, Weisberg, and other sources as noted, I have constructed the following table is from information adaptedįifth edition, by Monica Grady, The Handbook of Iron Meteoritesīy Vagn Buchwald, (University of California Press, 1975), and Meteorites and Their Parent Planets by Click on the diagrams for a larger image.
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