Siltstone

Siltstone is a geological term for a sedimentary rock whose composition is intermediate in grain size between the coarser sandstone and the finer mudstone. Siltstone Source: US Government File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Siltstone Source: US Government File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... World geologic provinces Oceanic crust  0-20 Ma  20-65 Ma  >65 Ma Geologic provinces  Shield  Platform  Orogen  Basin  Large igneous province  Extended crust Geology (from Greek γη- (ge-, the earth) and λογος (logos, word, reason))[1] is the science and study of the solid matter of a celestial body, its composition... Two types of sedimentary rock: limey shale overlaid by limestone. ... This article deals with grain size in the context of geology, see crystallite for grain size in materials science. ... Red sandstone interior of Lower Antelope Canyon, Arizona, worn smooth due to erosion by flash flooding over millions of years Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. ... Mudstone is a fine-grained sedimentary rock whose original constituents were clays or muds. ...

Description

As its name implies, it is primarily composed of silt, defined as grains smaller than 62 micrometres. Siltstones were at one time often referred to as sandstones, but differ significantly due to their smaller pores and higher propensity for containing a significant shale fraction. Although often mistaken as a shale, it lacks the fissility and laminations which are typical of shale. Siltstones are important geological elements in certain stratigraphic series, such as in Muldraugh Hill in Kentucky. They may contain concretions. Unless the siltstone is fairly shaly, stratification is likely to be obscure and it tends to weather at oblique angles unrelated to bedding. Silt is soil or rock derived granular material of a specific grain size. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the size of a droplet of mist or fog. ... Fissility refers to the property of mudstones to split along layers, more or less parallel to the plane of bedding, thus becoming described as shales. ... Muldraugh Hill is an escarpment in central Kentucky separating the Bluegrass on the north and north-east from the Pennyrile on the south and south-west. ... Official language(s) English[1] Capital Frankfort Largest city Louisville Area  Ranked 37th  - Total 40,444 sq mi (104,749 km²)  - Width 140 miles (225 km)  - Length 379 miles (610 km)  - % water 1. ... A concretion is a solid mineral inclusion within a rock strata that is oval or spherical in shape. ...

Holtzclaw siltstone, Louisville, Kentucky