what is silt ?

 

It is  the alluvium deposited by the rivers. Which is brought down by rivers and is deposited on slope of the mountain ,thereby forming plain.

Silt is created by a variety of physical processes capable of splitting the generally sand-sized quartz crystals of primary rocks by exploiting deficiencies in their lattice.^[1] These involve chemical weathering of rock^[2] and regolith, and a number of physical weathering processes such as frost shattering^[3] and haloclasty.^[4] The main process is abrasion through transport, including fluvial comminution, aeolian attrition and glacial grinding.^[5] It is in semi-arid environments ^[6] that substantial quantities of silt are produced. Silt is sometimes known as 'rock flour' or 'stone dust', especially when produced by glacial action. Mineralogically, silt is composed mainly of quartz and feldspar. Sedimentary rock composed mainly of silt is known as siltstone.