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As allothigen or allogeneic in are petrography components of rock , usually mineral grains or the corresponding mineral called that are not "in place" ( in situ incurred). The opposite of allothigen is authigen . Both names were introduced into the specialist literature in 1880 by the German geologist Ernst Kalkowsky .

In the case of sedimentary rocks , it refers to the rock components that - often over long distances - were transported by the sedimenting medium into the deposition space, for example the quartz grains of a quartz sandstone . As an alternative to being characterized as allothigenic , such sedimentary rock components are also referred to as detritic material , which refers to the fact that they emerged directly from the destruction of a parent rock .

In the case of igneous rocks , it refers to rock components that have not emerged from the same magma as the surrounding rock or that are not of igneous origin at all (see also →  Xenolite ).

See also


  • Hans Murawski, Wilhelm Meyer: Geological dictionary. 12th edition. Spektrum Akademischer Verlag, 2010, ISBN 978-3-8274-1810-4 , p. 6.

Individual evidence

  1. Ernst Kalkowsky: On the exploration of the archaic formations. New yearbook for mineralogy, geology and paleontology. Jhrg. 1880, Vol. 1, pp. 1–28 (p. 4, BHL ).