Sökning: "40Ar 39Ar"
Visar resultat 1 - 5 av 6 avhandlingar innehållade orden 40Ar 39Ar.
1. 40Ar/39Ar, AFT and (U-Th)/He thermochronologic implications for the low-temperature geological evolution in SE Sweden
Sammanfattning : The Oskarshamn and Forsmark areas in the Fennoscandian Shield, SE Sweden, have been chosen as potential sites for hosting highly radioactive nuclear waste. To evaluate their respective suitability, the geological history of the bedrock in these two areas has been investigated. This study has focused on the thermal evolution, from c. 500 °C to c. LÄS MER
2. The tectonic evolution of the western part of the Svecofennian orogen, central Sweden : Insight from U/Pb and 40Ar/39Ar geochronology at Forsmark
Sammanfattning : The Forsmark area, in the western part of the Svecofennian orogen, central Sweden, is situated between two major Palaeoproterozoic tectonic domains that show contrasting histories with respect to timing of igneous activity, ductile deformation and metamorphism. At Forsmark, WNW to NW trending, ductile deformation belts anastomose around tectonic lenses with an inferred lower degree of ductile strain. LÄS MER
3. Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques
Sammanfattning : The discovery, at the beginning of the 20th century, that elements can transform into other elements, due to the spontaneous decay of an instable to a stable atomic nuclei, gave rise to a powerful source for age information in many fields of earth science. For impact structures, it is crucial to establish well-defined and precise ages in order to understand how impact events affect the Earth’s geo and biosphere and also with regard to possible future events that can have devastating effects on our civilization. LÄS MER
4. Fluid migration and brittle tectonothermal evolution in the central Fennoscandian Shield - recorded by fracture minerals and wall rock alteration
Sammanfattning : The Forsmark area in central Sweden has been investigated as a potential geological host for a final repository of spent nuclear fuel by the Swedish Nuclear Fuel and Waste Management Company (SKB). High quality drill core material from the upper 1 km of the central Fennoscandian Shield has been obtained during the site investigations and has provided a unique opportunity for detailed fracture mineralogical investigations. LÄS MER
5. The Köli Nappe complex in Tännforsfältet western Jämtland, Swedish Caledonides
Sammanfattning : This dissertation presents the Köli Nappe Complex of Tännforsfältet, an area of some 1200 km2 of volcano-sedimentary eugeoclinal rocks occurring in a shallow synformal basin, the Tännforsen Synform. The rocks have been metamorphosed under greenschist-lower amphibolite facies conditions. LÄS MER
