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Psammit ( Greek psámmos "sand") is the name for medium-clastic sedimentary rocks (largely corresponds to a sandstone ) with grain sizes from 0.02 to 2 mm ( coarse silt to coarse sand ). The term can be used independently of the material, i. H. not only for clastic silicate rocks ( siliciclastics ), but also for clastic carbonate rocks. The medium-grain starting material can thus arise from the mechanical destruction of other rocks or consist of components (fossil fragments). However, the term Kalkpsammit is rarely used. In the carbonate petrography it corresponds to a calcarenite .

In the case of metamorphosis , psammites are given the prefix meta -, they become metapsammites like some types of mica schist .

In addition to the medium-clastic psammite, a distinction is made between fine- clastic ( pelite ) with grain sizes below 0.02 mm and coarse-clastic sediments ( psephite ) with grain sizes over 2 mm. As an alternative to the Pelit / Psammit / Psephit scheme for naming sedimentary rocks according to grain size, the terms claystone / siltstone / sandstone / conglomerate or breccia are used. In carbonate petrography, the term trio lutite / arenite / rudite is used much more often to describe or name rocks according to grain size.


  • Hans Murawski, Wilhelm Meyer: Geological dictionary . 11th edition. Elsevier / Spektrum, Heidelberg 2004, ISBN 3-8274-1445-8 , pp. 112, 118 and Tab. VI 1–12 .
  • Hans Füchtbauer (1988): 4. Sandstones. In: Hans Füchtbauer [Hrsg.], Sediment-Petrology, Part 2, Sediments and Sedimentary Rocks. 4th edition: 97-183, Stuttgart (Schweizerbart).