Sediments laid down by streams and rivers. The most common constituents are clay, silt, and gravel. The loose, unconsolidated material forms features such as river terraces, flood plains, and deltas.
Alluvium is deposited along the river channel where the water's velocity is too low to transport the river's load for example, on the inside bend of a meander.
The points of the star represent the first seven verses of the Koran. Red, black, white, and green became the pan-Arab colours. Effective date: 16 April 1928.