Origin of rock flour
First recorded in 1880–85
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for rock flour
Historical Examples of rock flour
Nearly all of the soil in the Park is rock-flour that was ground by glaciers, and in part distributed by them.
Mountains are moved piecemeal, and are ground to boulders, pebbles, and rock-flour in the moving.
Mountains were moved piecemeal, and ground to boulders, pebbles, and rock-flour in the moving.
British Dictionary definitions for rock flour
very finely powdered rock, produced when rocks are ground together (as along the faces of a moving fault or during the motion of glaciers) and are thus chemically unweathered
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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