Siltstone


Siltstone

Siltstone is a sedimentary rock which has a composition intermediate in grain size between the coarser sandstones and the finer mudstones and shales.

Description

As its name implies, it is primarily composed (greater than 2/3) of silt sized particles, defined as grains between 3.9 and 62.5 micrometres or 4 to 8 on the Krumbein phi (φ) scale. Siltstones differ significantly from sandstones due to their smaller pores and higher propensity for containing a significant clay fraction. Although often mistaken as a shale, siltstone lacks the fissility and laminations which are typical of shale. Siltstones 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.

References

*Folk, R.L., 1965, [http://www.lib.utexas.edu/geo/folkready/folkprefrev.html "Petrology of sedimentary rocks" PDF version] . Austin: Hemphill’s Bookstore. 2nd ed. 1981, ISBN 0-914696-14-9
*Williams, Howel, Francis J. Turner and Charles M. Gilbert, 1954, "Petrography", W. H. Freeman


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  • Siltstone — Le siltstone est une roche sédimentaire qui a une granulométrie (entre 1/256 et 1/16) comprise entre celle le grès, la plus grossière et la plus fine du mudstone et du schiste Utilisé comme pierre de dallage et de pavé, pierre de construction… …   Wikipédia en Français

  • siltstone — noun Date: circa 1920 a rock composed chiefly of silt hardened by heat, pressure, or cementation …   New Collegiate Dictionary

  • siltstone — /silt stohn /, n. Petrog. a very fine grained sandstone, mainly consolidated silt. [1925 30; SILT + STONE] * * * Hardened sedimentary rock that is composed primarily of angular silt sized particles (see silt) and that is not laminated or easily… …   Universalium

  • siltstone — noun A sedimentary rock whose composition is intermediate in grain size between the coarser sandstone and the finer mudstone …   Wiktionary

  • siltstone —    An indurated silt having the texture and composition of shale but lacking its fine lamination or fissility; a massive mudstone in which silt predominates over clay.    GG …   Glossary of landform and geologic terms

  • siltstone —    A type of schist which is dark gray and brown …   Glossary of Art Terms

  • siltstone — noun fine grained sedimentary rock consisting of consolidated silt …   English new terms dictionary

  • siltstone — silt•stone [[t]ˈsɪltˌstoʊn[/t]] n. pet a very fine grained sandstone, composed chiefly of consolidated silt • Etymology: 1925–30 …   From formal English to slang

  • siltstone — /ˈsɪltstoʊn/ (say siltstohn) noun a consolidated silt; a fine sandstone …   Australian English dictionary

  • siltstone — n. rock of consolidated silt …   Useful english dictionary


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