siltstone

siltstone
/silt"stohn'/, n. Petrog.
a very fine-grained sandstone, mainly consolidated silt.
[1925-30; SILT + STONE]

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Hardened sedimentary rock that is composed primarily of angular silt-sized particles (see silt) and that is not laminated or easily split into thin layers.

Siltstones, which are hard and durable, occur in thin layers rarely thick enough to be classified as formations. They are intermediate between sandstones and shales but are not as common as either.

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rock
      hardened sedimentary rock that is composed primarily of angular silt-sized particles (0.0039 to 0.063 mm [0.00015 to 0.0025 inch] in diameter) and is not laminated or easily split into thin layers. Siltstones, which are hard and durable, occur in thin layers rarely thick enough to be classified as formations.

      Siltstones are intermediate between sandstones and shales (shale) but are not so common as either. They contain less alumina, potash, and water than shales but more silica; in addition to mica, they may contain abundant chlorite and other micaceous clay minerals. Although many shales contain more than 50 percent silt, not all are siltstones; siltstones differ from these shales in that they commonly are chemically cemented and show such features as cross-bedding (i.e., lamination inclined to the main bedding plane), cut-and-fill structures, and flowage within a layer. See also mudstone.

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Universalium. 2010.

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Look at other dictionaries:

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  • 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,… …   Wikipedia

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

  • 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 …  

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

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