Psephite

Psephit (Greek: psẽphos " stones " ) is the name for coarse clastic sedimentary rocks with grain sizes of about 2 mm. After the geotechnical grain size classification, equivalent to the stone sizes of gravel and conglomerates and breccias. The term can be used irrespective of the material, that is, not only for clastic silicate rocks, but also for clastic carbonate rocks. However, the term Kalkpsephit find almost no use. In this Karbonatpetrographie a limestone particle size is called Kalkrudit. In the case of a metamorphosis Psephite get the prefix meta, they will Metapsephiten.

The coarse-grained raw material comes from the mechanical destruction of other rocks. This happens, for example, by frost damage on rock walls and blocks so that the fragments accumulate as rock rubble in rubble or boulders. Flow Transport sharp rock fragments are converted into pebbles.

In addition to the coarse clastic Psephit distinction is fine clastic pelites ( with particle sizes less than 0.02 mm, eg clays ) and medium- clastic sedimentary rocks ( Psammite ), whose grain sizes 0.02-2 mm ( coarse silt to coarse sand). Alternatively, the schema pelitic / psammite / Psephit naming siliciclastic sedimentary rocks according to particle size, the terms are applied mudstone / siltstone / sandstone / conglomerate or breccia. In the Karbonatpetrographie the term trio Lutit / arenite / Rudit is used for the description or naming of rocks on grain sizes much more common.