Angrite (Evolved) Meteorites for Sale

Angrite (Evolved)

Type of evolved achondrite meteorite that represent some of the earliest stages of asteroidal differentiation and magmatism (~4.56 Ga) in our solar system. Angrites are named for the Angra dos Reis meteorite, which fell in Rio de Janeiro, Brazil, in early 1869. They are basaltic (mafic) rocks, often containing porous areas and many round vesicles (small cavities) with diameters up to 2.5 cm. Angrites are the most ancient igneous rocks known, with crystallization ages of around 4.55 Ga. They are thought to have formed on one of the earliest differentiated asteroids. By comparing the reflectance spectra of the angrites to that of several main belt asteroids, two potential parent bodies have been identified: 289 Nenetta and 3819 Robinson.

Angrites are composed mainly of augite (Wo>50; “fassaite”), olivine (Fa10-100) that exsolved into the solid solutions of monticellite-kirschsteinite and forsterite-fayalite, plagioclase (An100) and troilite.

The 53Mn-53Cr chronometer has been used successfully to date the magmatic events of many of the volcanic angrites, but dating of angrites with a more extensive thermal history (e.g. plutonic angrites) yields younger ages.

Content above used with permission from J. H. Wittke.

 

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