Authigenic education
As authigen be in the petrography components of rock , usually mineral grains or aggregates or the corresponding mineral, called the "in place" have emerged. The opposite of authigen is allothigen . Both names were introduced into the specialist literature in 1880 by the German geologist Ernst Kalkowsky .
In the case of sedimentary rocks, it is used to describe rock components that have only formed after the sediment has been deposited, e.g. B. Glauconite or pyrite (see also → Diagenesis ). Sometimes the term is also used for the entire rock, for example limestones, which mainly consist of material that was passively precipitated directly from the water column or deposited by organisms in the deposition area. In this context, one speaks of autochthonous or in situ formed sediments or sedimentary rocks. A rock that can be called authentic in the true sense of the word is phosphorite , as the phosphate deposition actually takes place early diagenetically.
In the case of igneous rocks , authigen means that the corresponding components have emerged through crystallization from one and the same magma or one and the same lava.
In metamorphic rocks , all those minerals are authentic that were formed during the metamorphosis.
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- Christiane Martin, Manfred Eiblmaier (Ed.): Lexicon of Geosciences. In six volumes. Spectrum, Academic Publishing House, Heidelberg [u. a.] 2000-2002.
- Hans Murawski, Wilhelm Meyer: Geological dictionary. 12th edition. Spektrum Akademischer Verlag, 2010, ISBN 978-3-8274-1810-4 , p. 13.