Dear etaoin: comminutes is almost the exact word the man said. The Nivation article was the second of two, and in the third or fourth paragraph you will find his words:
"This repeated freezing and thawing acomminutes the rock particles."

Remember years ago, prison "hard labor" meant making little ones out of big ones." Incidentally, this is the process that produces the "cirques" which used to puzzle me.

cirque
n.
5Fr < L circus: see CIRCUS6
1 a circular space or arrangement
2 [Old Poet.] a circle; ring
3 [Archaic] a circus
4 Geol. a steep, hollow excavation high on a mountainside, made by glacial erosion; natural amphitheater