A eucrite achondrite from the Millbillillie meteorite shower.
An achondrite[1] is a stony meteorite that does not contain chondrules.[2][3] It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies.[4][5] As a result, achondrites have distinct textures and mineralogies indicative of igneous processes.[6]
Achondrites account for about 8% of meteorites overall, and the majority (about two-thirds) of them are HED meteorites, possibly originating from the crust of asteroid 4 Vesta. Other types include Martian, Lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of e.g. the Fe/Mn chemical ratio and the 17O/18O oxygen isotope ratios, thought to be characteristic "fingerprints" for each parent body.[7]
^Etymology: from the prefix a- (privative a) and the word chondrite.
^Recommended classifications: Eucrite-pmict
^Achondrite, Encyclopædia Britannica
^Sahijpal, S.; Soni, P.; Gagan, G. (2007). "Numerical simulations of the differentiation of accreting planetesimals with 26Al and 60Fe as the heat sources". Meteoritics & Planetary Science. 42 (9): 1529–1548. Bibcode:2007M&PS...42.1529S. doi:10.1111/j.1945-5100.2007.tb00589.x.
^Gupta, G.; Sahijpal, S. (2010). "Differentiation of Vesta and the parent bodies of other achondrites". J. Geophys. Res. Planets. 115 (E8). Bibcode:2010JGRE..115.8001G. doi:10.1029/2009JE003525. S2CID 129905814.
^Mason, B. (1962). Meteorites. New York: John Wiley.
^Mittlefehldt, David W.; McCoy, Timothy J.; Goodrich, Cyrena Anne; Kracher, Alfred (1998). "Non-chondritic Meteorites from Asteroidal Bodies". Reviews in Mineralogy and Geochemistry. 36 (1): 4.1–4.195.
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been...
Primitive achondrites are a subdivision of meteorites. They are classified on the same rank (historically called "Class") and lying between chondrites...
the IAB group/complex. IAB meteorite – an iron meteorite and primitive achondrite of the IAB group/complex. IB meteorite – an iron meteorite group now part...
meteorites are a clan (subgroup) of achondrite meteorites. HED stands for "howardite–eucrite–diogenite". These achondrites came from a differentiated parent...
Aubrites are a group of meteorites named for Aubres, a small achondrite meteorite that fell in 1836 in Aubres near Nyons, France. They are primarily composed...
primitive achondrites or as asteroidal achondrites. Like all primitive achondrites, they have similarities with chondrites and achondrites. Brachinites...
Lodranites are a small group of primitive achondrite meteorites that consists of meteoric iron and silicate minerals. Olivine and pyroxene make up most...
group with <5 members) Achondrites Primitive achondrites Acapulcoite group Lodranite group Winonaite group Asteroidal achondrites HED meteorite clan (possibly...
Acapulcoites are a group of the primitive achondrite class of stony meteorites. The acapulcoites are named after the only specimen of the group, with a...
group of primitive achondrite meteorites. Like all primitive achondrites, winonaites share similarities with chondrites and achondrites. They show signs...
Vesta and are part of the HED meteorite clan. They are the most common achondrite group with over 100 meteorites found. Eucrites consist of basaltic rock...
melting and impact events and are grouped with the primitive achondrites and the achondrites. Iron meteorites are derived from planetary cores of asteroids...
homes were built in Tataouine. On June 27, 1931, a meteorite of unusual achondrite type and green color impacted at Tataouine; about 12 kg of fragments were...
and nickel content. Non-metallic meteorites that lack chondrules are achondrites, which are believed to have formed more recently than chondrites. There...
Angrites are a rare group of achondrites consisting mostly of Al-Ti bearing diopside, hedenbergite, olivine, anorthite and troilite with minor traces...
into a thin fusion crust, which on most meteorites is black (on some achondrites, the fusion crust may be very light-colored). On stony meteorites, the...
about 1000 °C. A geological name for ureilite would be olivine-pigeonite achondrite. Compared to most other meteorites, ureilites tend to have a high percentage...
Alexandra Range in Antarctica. Compositional type Stony Type Achondrite Class Asteroidal achondrite Clan HED meteorite Parent body 4 Vesta Total known specimens...
accessible to scientists, in the form of over 1200 HED meteorites (Vestan achondrites), giving insight into Vesta's geologic history and structure. NASA Infrared...
Mittelfehldt D (1996). "Mineralogy of carbonaceous chondrite clasts in HED achondrites and the moon". Meteoritics & Planetary Science. 31 (4): 518–537. Bibcode:1996M&PS...
Lunar meteorite (Lunaite) — Clan — Lunar meteorite Allan Hills 81005 Type Achondrite Subgroups Highland breccia Mare basalt Parent body Moon Total known specimens...
called chondrites. Stony meteoroids without these features are called "achondrites", which are typically formed from extraterrestrial igneous activity;...
Johnstown Diogenite. Type Achondrite Structural classification Igneous rocks of plutonic origin Class Asteroidal achondrite Clan HED Parent body 4 Vesta...
meteorites according to their overall composition and a group of primitive achondrites because of silicate inclusions that show a strong affinity to winonaites...
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