Silicated Iron-Nickel meteorites are very rare and important because their silicates match up with the also-rare primitive achondrites like Winonaite (same oxygen and Mo isotope profiles and minerology). Matching up with Winonaite means that this IAB NWA 5549 originated from the same parent body. Winonaites came from closer to the surface and NWA 5549 from deep in the core of the yet-to-be discovered planetesimal body.
Recent research (below) indicate that the planetoid had differentiated into four layers, with a molten iron core, but it then suffered a massive collision destroying the entire parent body to its molten core (the metal matrix of this specimen). The bulk of the material reassembled into a large asteroid, ending its magmatic evolution and preserving the type of differentiation processes that occurred on accreting asteroids in the early Solar System
The Winonaites show that the parent body was affected by impacts that formed breccias of different lithologies. Later these breccias were heated and Ar-Ar radiometric ages have constrained the metamorphism on the parent body to between 4.40 and 4.54 billion years. The parent body also reached temperatures where partial melting took place. Cosmic ray exposure ages show that the meteorites took about 20 to 80 million years to reach earth.
This specimen has been polished and etched showing many silicate inclusions in the iron-nickel fields. The silicate inclusions are chondritic in chemical composition but being recrystallized makes them an achondrite.
Silicated Iron (IAB-MG)
Found 2008 in Algeria
1,252gm, 9” x 10” x 3/16”
The largest slice of this beautiful voyager from outer space.
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