Sökning: "40Ar 39Ar dating"

Hittade 4 avhandlingar innehållade orden 40Ar 39Ar dating.

1. 1. Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques

   Författare :Maria Herrmann; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Impact structure; Dating impact events; 40Ar 39Ar dating; U-Pb dating; Siljan impact structure; Mien impact structure; Hummeln impact structure; Puchezh-Katunki impact structure;

   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

3. 2. The tectonic evolution of the western part of the Svecofennian orogen, central Sweden : Insight from U/Pb and 40Ar/39Ar geochronology at Forsmark

   Författare :Tobias Hermansson; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; physical geography; Geology; Svecofennian orogen; Tectonic models; Tectonic cycles; Uplift; Cooling; Ductile deformation; Geochronology; U Pb; 40Ar 39Ar; Geologi; fysisk geografi; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; geokemi;

   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

4. 3. Proterozoic to Quaternary Events of Fracture Mineralisation and Oxidation in SE Sweden

   Författare :Henrik Drake; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fracture minerals; low-temperature evolution; paleohydrogeology; redox front; wall rock alteration; stable isotopes; geochemistry; Ar-Ar dating; fluid inclusions; Mössbauer spectroscopy; U-series disequilibrium; Simpevarp; Laxemar; SE Sweden; nuclear waste repository.;

   Sammanfattning : Fracture minerals and altered wall rock have been analysed to reveal the low-temperature evolution, especially regarding redox conditions, of the Simpevarp area, SE Sweden. This area is one of the two areas in Sweden investigated by the Swedish Nuclear fuel and Waste Management Co. LÄS MER

5. 4. Fluid migration and brittle tectonothermal evolution in the central Fennoscandian Shield - recorded by fracture minerals and wall rock alteration

   Författare :Björn Sandström; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   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