Striae or striations

Linear fine scratches formed by the abrasive effect of debris-rich ice sliding over bedrock. Intersecting sets of striae are formed as stones are rotated, or if the direction of flow over bedrock changes.

Exceptionally well-preserved striated pavement of Permo-Carboniferous age (c. 290 m.y. old) near Douglas in the Great Karoo region of South Africa. Photo M. J. Hambrey.