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A chondrule (from Ancient Greek χόνδρος chondros, grain) is a round grain found in a chondrite. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids .
A chondrite / ˈ k ɒ n d r aɪ t / is a stony (non-metallic) meteorite that has not been modified by either melting or differentiation of the parent body. [a] [1] They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids.
The chondrule size is only about 0.15 mm on average. They are all of petrologic type 3. Famous CO chondrite falls: Ornans; Kainsaz; Warrenton; Moss; Famous finds:
Primitive achondrites are a subdivision of meteorites.They are classified on the same rank (historically called "Class") and lying between chondrites and achondrites.They are called primitive because they are achondrites that have retained much of their original chondritic properties.
Chondrule glass: Altered or absent: Mostly altered, some preserved: Clear, isotropic: Devitrified: Absent Metal: Maximum Ni content – <20% Taenite minor or absent >20% kamacite and taenite in exsolution relationship Sulfides: Mean Ni content – >0.5% <0.5% Overall Texture: No chondrules: Sharp chondrule boundaries: Some chondrules can be ...
The tiny mass of asteroids may be partly due to inefficient chondrule formation beyond 2 AU, or less-efficient delivery of chondrules from near the protostar. [35] Also, impacts controlled the formation and destruction of asteroids, and are thought to be a major factor in their geological evolution.
E-type chondrites are among the most chemically reduced rocks known, with most of their iron taking the form of metal or sulfide rather than an oxide. They tend to be high in the mineral enstatite (MgSiO 3), from which they derive their name. [1]
However, most LL chondrites have been thermally metamorphosed to petrologic types 5 and 6, meaning that their minerals are homogeneous in composition and chondrule borders are difficult to discern. This, together with the low content of metal, led the 19th century mineralogist Tschermak to determine that they formed a transitional stage between ...