PEBBLE

A 'pebble' is a clast of rock with a particle size of 4 to 64 millimeters based on the Krumbein phi scale of sedimentology. A rock made predominantly of pebbles is termed a conglomerate.


Pebble tools are among the earliest known man-made artifacts, dating from the Palaeolithic period of human history. They have been found at Olduvai Gorge (1.85 million years ago) and at Longuopo in China (1.8 to 1.5 MYA).
A beach composed chiefly of surface pebbles is commonly termed a shingle beach, which has armoring characteristics with respect to wave erosion; moreover, this type of beach has unusual ecological niches that may provide habitat for a number of rare and endangered species.

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See also

See also

★ Gravel