Fig. 5: Proposed formation history of the Chelyabinsk meteorite.
From: Ancient and recent collisions revealed by phosphate minerals in the Chelyabinsk meteorite
Schematic view of collisions affecting the source material of Chelyabinsk on the LL parent body. Early radiogenic metamorphism gives way to cooling of the parent body. A primary collision locally produces shock melt at the surface of the asteroid, which cools relatively quickly (shock-induced features incompletely annealed during post-shock thermal metamorphism). A later spalling event is then needed to liberate the Chelyabinsk material from the LL parent body, and may be responsible for late Pb loss and lower intercept ages.
