Origin and tectonic significance of a mixed meta-peridotite and meta-sedimentary complex between the Jotun nappe and the Western Gneiss Complex near Sogndal, Western Norway
A melange (mixed) unit of rocks has been mapped at low structural levels above the Western Gneiss Complex across South Norway all the way from the Bergen area towards Otta and beyond.
The typical feature of the melange is that it consists of meta-peridotites mixed with original sediments and sheets of ancient gneisses. In the mountains north-west of Sogndal two major meta-peridotite bodies have been identified in a reconnaissance study but their lithological, structural and metamorphic setting is unknown so far.
With these two master projects we would like to find out:
- What are the exact lithologies (mafic vs. ultramafic) and metamorphic alterations in these two bodies? This requires detailed field mapping of the two bodies (ca. 0.6x0.6km and 0.2x0.2km) and their contact relationships with the wall rocks as well as petrological and geochemical investigations.
- The second project involves detailed and kilometre scale mapping to answer: What are the surrounding metasedimentary rocks, type, structures, metamorphic grade and depositional age? This study requires mapping on a bigger scale as well as detrital zircon geochronology, which is crucial to unravel the Neoproterozoic vs. Paleozoic part of the history.