Oslograben
The Oslograben (Norwegian Oslofeltet ) is a geological trench in the earth's crust near the Norwegian capital Oslo .
The rift formation falls in the time of the Variscan orogeny and begins as early as the late Carboniferous . In the Permian , the landscape sank and it was mainly formed by volcanic cover rocks, which can be seen, for example, in basaltic rock types and in porphyry rocks such as rhombic porphyries and ignimbrites .
In the course of this intensive volcanic development, several calderas formed , which, however, are no longer recognizable in the landscape by their morphological features. More rare rocks such as nepheline syenite, Tinguait , Nordmarkit , Ekerit , syenite ( Larvikit ) and Tönsbergit than the red variety are here open-minded . Some of these sites are internationally known and significant.
The activity ended with uplifts and intrusions after about 65 million years in the Early Triassic .
Web links
Individual evidence
- ↑ Per Smed, Jürgen Ehlers (trans.): Stones from the north . Berlin, Stuttgart, 1994, ISBN 3-443-01030-X , pp. 81-83