Naturmuseum Frankfurt

Basalt 2013
4 Special Session

One hundert years passed since the publication of the Dissertation by Karl Hermann Scheumann, a young graduate of the University of Leipzig. The autor presented the result of his research of ultramafic volcanic rocks in northern Bohemia. With regard to the exceptional composition associated with the presence of melilite and the absence of clinopyroxene, Scheumann introduced the name polzenite for these dyke rocks, now still in use. It is derived from the name of Polzen-Ploučnice River flowing through this region. The local varieties were named vesecite, modlibovite, luhite (with cliniopyroxene) and wesselite (free of melilite). From the today‘s perspective, it is necessary, however, to update the abov terms and revise them, where needed. Some of the Scheumann‘s type localities are hardly to be found. The purpose of recent studies, the preliminary results of which are presented for discussion, is to make access to the most significant outcrops, to provide their systematic documentation with the use of modern methods, and to verify and complete older data. New, in the last 30-40 years recoverd and partly still unpublished results extend significantly Scheumanns’s original scope both in its content and regional extent. The current discussion focuses on the relatively high age of the volcanics, on the structural geology of the dyke-systeme of melilitic rocks (Devil’s Wall type, Bohemian Massif), including the clarification of causal relationships between the magma emplacement and tectonic activity as well as magma generation and evolution of such extremely undersaturated rocks. Selected localities are valuable and unique objects of study. Projects on their protection have been prepared and are also open to discussion.
Therefore we invite contributions dealing with ultramafic rocks, e.g. melilite rich volcanics of other regions or carbonatites and kimberlites from the field geological, geochemical, mineralogical and petrogenetic point of view.
All contributions could be finished as a resarch paper into a special issue of the Journal of Geosciences - call for papers you find here.



     Jaromir Ulrych (Praha/CZ)
     Vladislav Rapprich (Praha/CZ)
     Antonin Paluska (Praha/CZ)

Key Notes  
Frantisek Holub (Prague/CZ) "Revision of Scheumanns definition of polzenitic rocks"