Eucrite
Eucrite
Achondritic stony meteorite
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.
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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).[1]
Based on differences of chemical composition and features of the component crystals, they are subdivided into several groups:[2]
- 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.