Theory 17/Meteoritics
Chondrules Freeze on a Ratio
The claim
Chondrule texture is set by the ratio of cooling rate to nucleation rate rather than by peak temperature, so the same peak produces different textures.
01The mechanism
Crystal size depends on how many nuclei form before the melt cools; the ratio sets whether the result is fine-grained, porphyritic or glassy.
02Predictions
- P1Texture should map onto the ratio.
- P2Peak temperature alone should not predict texture.
03Refutation
Texture tracking peak temperature would remove the kinetic ratio.