Angela C. Dobson

B. Sc. Honours Thesis

A Study of the Silica-Undersaturated Alkaline Rocks of the Laacher Sea Area, East Eifel Volcanic Field, West Germany

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The generation of alkaline rocks is a complex process. The East Eifel volcanic field in West Germany represents the most alkalic rocks in the alkaline province of Central Europe and France. The area of particular interest, in this study, the Laacher Sea.

The rocks in this study include phonolites (including selbergites), tephritic phonolites, nephelinites and phonolitic tuffs. They have been divided into two major groups; mafic (M) and felsic (F) on the basis of petrographical, major and trace element geochemical and mineralogical analyses. Group M can be further subdivided into two subgroups: Group M-1 is composed of nephelinites and Group M-2 is composed of phonolites.

The samples from Group M and F are intricately related in space and are approximately the same age. These observations together with the experimental results indicate that all the groups are petrogenetically related.

Keywords:
Pages: 123
Supervisor:  James Hall