Silt semi-arid environments 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. Liquefaction created by a strong earthquake is silt suspended in water that is hydrodynamically forced up from below ground level. In the Udden–Wentworth scale (due to Krumbein), silt particles range between 0.0039 and 0.0625 mm, larger than clay but smaller than sand particles. ISO 14688 grades silts between 0.002 mm and 0.063 mm (sub-divided up into
Gravel chub type of habitat, increasing the turbidity of the current and the amount of silt in rivers and streams. Populations in southern Minnesota are experiencing a great amount of stress due to the large amount sediment deposit from the Mississippi River that disturbs flow regimes. The Minnesota DNR has been continuing to monitor and improve water quality of rivers and streams in southern Minnesota. Iowa and New York also have put extra conservation efforts towards the gravel chub. In Iowa the gravel chub was once threatened, but now abundant all over the state. In New York there has been a strong