Sökning: "geologi"

Visar resultat 21 - 25 av 621 avhandlingar innehållade ordet geologi.

1. 21. Precambrian and Caledonian history of Svalbard’s West Ny Friesland Terrane

   Författare :Fredrik Hellman; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geologi; physical geography; Geology; Detrital; Zircon; Svalbard; Caledonides; Spitsbergen; fysisk geografi; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; geokemi;

   Sammanfattning : This thesis deals mainly with age-investigations of metasedimentary and magmatic rocks of Ny Friesland, located in the northeastern Svalbard. However, the provenance of quartz-porphyry clasts in a Devonian conglomerate have also been investigated in northwestern Svalbard. LÄS MER

3. 22. 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. 23. Geochemical Development of Proterozoic Granites in the SW Baltic Shield

   Författare :Kirsten Holme; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; principal component analysis; granite classification; magma evolution; magma genesis; granite; Eastern Segment; Western Segment; Southwestern Swedish Gneiss Complex; Sweden; Sveconorwegian Orogen; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; geokemi; Geology; physical geography; Geologi; fysisk geografi;

   Sammanfattning : The plutonic rocks in the Western Segment of the Southwestern Swedish Gneiss Complex show a distinct geochemical evolution. The 1.6 Ga Åmål granitoids and Slottsbron migmatites are a quartz dioritic to granodioritic, calc-alkaline rock suite with smooth, but somewhat fractionated, REE and other trace-element patterns. LÄS MER

5. 24. Pollen analysis, chronology and palaeomagnetism of three Late Weichselian sites in southern Sweden

   Författare :Jonas Ising; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; southern Sweden; calendar year chronology; Late Weichselian; Pollen stratigraphy; palaeomagnetic secular variations; Geology; physical geography; Geologi; fysisk geografi;

   Sammanfattning : Three sites, Torreberga in Skåne, Farslycke in Blekinge and Lake Bolmen in Småland, with Late Weichselian lake sediments were studied with respect to pollen analysis and palaeomagnetism. The chronologies are based on pollen stratigraphical correlations, radiocarbon dating and, for two of the sites, on a clay-varve chronology. LÄS MER

7. 25. The Ups and Downs of the Holocene: Exploring Relationships between Global CO2 and Climate Variability in the North Atlantic Region

   Författare :Catherine Jessen; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marklära; geomorfologi; climatology; klimatologi; rapid climate change; Holocene climate; atmospheric CO2 concentrations; geochemical proxy indicators; Paleobotanik; palynology; Geology; palynologi; fylogeni; geomorphology; fysisk geografi; Geologi; physical geography; kartografi; pedology; cartography; phylogeny; Palaeobotany; stomatal frequency; lake sediments;

   Sammanfattning : This thesis aimed to examine the relationship between climate and atmospheric CO2 concentrations through rapid climate changes during the Holocene. Climate was reconstructed using high-resolution, radiocarbon dated, lake sediment geochemical proxies (magnetic susceptibility, loss-on-ignition, total carbon/nitrogen/sulphur determinations and biogenic silica), vegetational reconstruction (pollen analysis) and stomatal frequency based CO2 reconstructions. LÄS MER