Gravel:
Gravel is an unconsolidated accumulation of rounded fragments greater than 2 mm in diameter.
Wentworth (1922) classified gravel into four types on the basis of size (diameter in mm)
(a) Boulder above 256 mm
(b) Cobble 256-64 mm
(c) Pebble 64-4 mm
(d) Granule 4-2 mm
Classification of gravel:
Bank gravel:
Naturally deposited gravel intermix with sand or clay and found in rivers and streams, also known as ‘bank run’ or ‘river run’.
Beach gravel:
A bed of gravel located on the side of the valley above the present stream bottom, indicating the former location of the stream bed when it was at a higher level.
Lag gravel:
A surface accumulation of coarse gravel produced by the removal of finer particles.
Pay gravel:
It is also known as ‘pay dirt a nickname for gravel with a higher concentration of. Gold and other precious metals are recovered through gold panning.
Pea gravel:
Gravel that consists of small, rounded stones used in concrete surfaces. Also used for walkways, driveways, and as a substrate in home aquariums.
Peidmont gravel:
A coarse gravel carried down from higher places by mountain streams and deposited on relatively flat ground, where the water runs more slowly.
Plateau gravel:
A layer of gravel on a plateau or other region above the height at which stream-terrace gravel is usually found.
