eucrite

{{Short description|Achondritic stony meteorite}}

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{{Infobox meteorite subdivision

|Subdivision = Group

|Name = Eucrite

|Alternative_names =

|Image = Meteor Stonařov u Jihlavy.jpg

|Image_caption = Stannern eucrite, found in the Czech Republic.

|Image_alt_text =

|Compositional_type = Stony

|Type = Achondrite

|Class = Asteroidal achondrite

|Clan = HED meteorite

|Group =

|Subgroups = {{Plainlist|

• Non-cumulate eucrites
• Main series eucrites
• Stannern trend eucrites
• Nuevo Laredo trend eucrites
• Cumulate eucrites
• Polymict eucrites

}}

|Structural_classification =

|Parent_body = 4 Vesta and others

|Composition = Basaltic rock, mostly Calcium-poor pyroxene, pigeonite, and Calcium-rich plagioclase (anorthite)

|Petrologic_type =

|Number_of_specimens = >100

|TKW =

|Image2 = Eucrite GRA98033.jpg

|Image2_caption = GRA98033 a brecciated eucrite about 5 cm across, found in the Graves Nunataks region of Antarctica.

|Image2_alt_text =

}}

Eucrites are achondritic stony meteorites, many of which originate from the surface of the asteroid 4 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 from the crust of 4 Vesta or a similar parent body. They are mostly composed of calcium-poor pyroxene, pigeonite, and calcium-rich plagioclase (anorthite).B. Mason: Meteorites. John Wiley, New York 1962.

Based on differences of chemical composition and features of the component crystals, they are subdivided into several groups:Mittlefehldt, McCoy, Goodrich and Kracher: Non-chondritic Meteorites from Asteroidal Bodies, In: Reviews in Mineralogy Vol. 36, Planetary Materials, Mineralogical Society of America, 1998.

• Non-cumulate eucrites are the most common variety and can be subdivided further:
• Main series eucrites formed near the surface and are mostly regolith breccias lithified under the pressure of overlying newer deposits.
• Stannern trend eucrites are a rare variety.
• Nuevo Laredo trend eucrites are thought to come from deeper layers of 4 Vesta's crust, and are a transition group towards the cumulate eucrites.
• Cumulate eucrites are rare types with oriented crystals, thought to have solidified in magma chambers deep within 4 Vesta's crust.
• Polymict eucrites are regolith breccias consisting of mostly eucrite fragments and less than one part in ten of diogenite. They are less common.