The concept of the thesis pertains to the differentiation of spodumene-bearing pegmatites from their host rocks (eclogite-amphibolite or kyanite-garnet-mica schist) using geophysical prospecting, with magnetism being the preferred method. To establish a correlation between geophysical data and the lithology of the subsurface, geophysical measurements are taken parallel to pre-existing boreholes. The verification of potential correlations is specified through the characterisation of mineralogy, as well as susceptibility and remanent natural magnetisation. The feasibility of magnetic prospecting relies on the measurable contrast between the host rock and the pegmatites, caused by their differing mineralogical associations.
Susceptibility enables a clear distinction between the pegmatite and the host rocks. Internal textures and contact phenomena are observable in eclogite-amphibolite through aplitic border zones and biotitisation, and in mica schist through tourmalinisation. The differences in mineralogical composition of "amphibolite-hosted pegmatites" and "mica schist-hosted pegmatites" are clearly evident. Pyrrhotite has been identified as the indicator mineral for the magnetic anomalies. A challenge in the magnetic prospecting for pegmatites is the clear separation of lithologies due to the interbedding of thin lithologies and the enrichment of magnetic minerals in the host rock lithologies and the pegmatites. These conditions limit the extent to which anomalies can be attributed to the ferromagnetic lithologies of the borehole cores.
In conclusion, it can be stated that the correlation of magnetic anomalies and the susceptibility of the borehole cores leaves room for questions.