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 Ridge, Arkansas $44,318. Males had a median income of $31,553 versus $21,903 for females. The per capita income for the CDP was $16,932. About 7.9% of families and 8.5% of the population were below the poverty line, including 10.6% of those under age 18 and 12.9% of those age 65 or over. The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Gravel Ridge has a humid subtropical climate, abbreviated "Cfa" on climate maps. Gravel Ridge, Arkansas Gravel Ridge is a former census-designated place (CDP) in Pulaski County,