Petrographie des kristallinen Grundgebirges der Nordschweiz und Systematik der herzynischen Granite

Abstract

The North Swiss crystalline basement is hidden beneath a sedimentary cover of variable thickness. It has been penetrated by several exploration drillholes aimed at coal, oil, gas, salt or thermal water. In recent years, 6 deep drillholes supplying long basement profiles were conducted by NAGRA. Similar to the outcrops in the Southern Black Forest, the North Swiss crystalline basement consists of Pre-Hercynian high-grade gneisses which were intruded by Hercynian plutons. The gneiss series is dominated by paragneisses (6 boreholes; mainly metapelites and meta-graywackes), and minor orthogneisses (1) and banded, amphibolite-rich series (2) were encountered. The Hercynian plutons comprise mainly granites (15) whereas K-rich basic intrusives were recovered from one single site