Magnesite - Veitsch, Styria


 
Description: Sparry magnesite, partly with pinolitic texture, along a "vein" in fossil-rich dolomite. Enrichment of the clay minerals and
organic matter of the dolomite at the edges and between magnesite crystals can be observed (black rims around and between magnesite).
Genesis: Partial metasomatic replacement of clay- and organic-rich, Carboniferous dolomite, resulting in a concentration of the clay minerals
and the organic material at the grain boundaries of magnesite. But the genesis remains controversal, especially the time of magnesite formation.
It could be either: very early diagenetic(?); late diagenetic; due to a hydrothermal event in the Permo-Triassic; during Eo-Alpine metmorphism.
One of the problem is the undoubted Eo-Alpine greenschist facies overprint of the magnesite-bearing series, possibly resulting in
recrystallization, redistribution of magnesite and the obliteration of pre-Eo-Alpine textures.
Time of magnesite formation: Possibly Permo-Triassic.
Locality: Abandoned magnesite mine Sattlerkogel, Veitsch, Styria, Austria.
References: Prochaska, 2001
Sample details: Collected 25.5.2002. Polished slab. Field of view 17 cm. Sample AN87.
last changes: 29.10.2003