Sökning: "mineral magnetic analysis"

Visar resultat 26 - 30 av 33 avhandlingar innehållade orden mineral magnetic analysis.

1. 26. Crystal chemistry of Fe-Ti oxides in mafic rocks and metabasites: A study aimed at refinement of geological tools and interpretations

   Författare :Benyam Estifanos; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fe-Ti oxide; hercynite; siderite; stilpnomelane; olivine corona; Swedish Caledonides; hysteresis; PIXE; synchrotron XRD; Rietveld; microprobe; red corundum; palaeomagnetism; eclogite; plagioclase clouding; dolerite; pyroxene gneiss; Geology; physical geography; Geologi; fysisk geografi;

   Sammanfattning : This thesis consists of four subprojects: (A) ‘Clouding of plagioclase by Fe-Ti oxides’, (B) ‘Fe-Ti oxides during high-pressure metamorphism of mafic rocks’, (C) ‘Magnetic study of Fe-Ti oxides in mafic rocks and metabasites’, and (D) ‘Topotactic phase transitions in oxide minerals’. A) In southern Sweden dolerite dikes and gabbros with clouded plagioclase are common. LÄS MER

3. 27. Late Weichselian and early Holocene changes of vegetation, climate and sea level on the Skagi peninsula, northern Iceland

   Författare :Mats Rundgren; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asthenosphere viscosity; glacial loading unloading; marine polar front migrations; sea-level change; climate change; vegetation change; Early Holocene; Late Weichselian; Iceland; Lake sediments; Skagi peninsula; Geology; physical geography; Geologi; fysisk geografi;

   Sammanfattning : Sediment sequences from five lakes on the Skagi peninsula, northern Iceland, were subjected to mineral magnetic analysis, carbon analysis, pollen analysis, plant macrofossil analysis, diatom analysis, radiocarbon dating and tephra analysis in order to make detailed reconstructions of vegetation, climate and sea level during the Late Weichselian and Early Holocene. The main purpose was to investigate if the dramatic deglacial climatic shifts recorded in proxy records from the North Atlantic region, such as ice cores, marine sediments and lake sediments, also are registered in Skagi lake sediments, which would be expected considering Iceland´s position in the middle of the North Atlantic Ocean, within the range of the Late Weichselian–Early Holocene migrations of the marine polar front. LÄS MER

4. 28. Novel boron compounds in lubrication

   Författare :Mamoun Taher; Mark Rutland; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry of Interfaces; Gränsytors kemi;

   Sammanfattning : Lubricants are used to control friction and reduce wear by preventing direct contact between surfaces in a relative motion. Most of the modern lubricants and lubricant additives have been designed and optimized for ferrous materials. LÄS MER

5. 29. Integrated analyses and interpretations of regional scale magnetotelluric and potential field data from the Precambrian crust of northern Sweden

   Författare :Roshanak Vadoodi; Thorkild Maack Rasmussen; Maxim Smirnov; Björn H. Heincke; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Exploration Geophysics; Prospekteringsgeofysik;

   Sammanfattning : The Norrbotten region in northern Sweden, as a part of the Fennoscandian (Baltic) Shield, is one of the most active mining areas in Europe. It is acknowledged that geological structures such as faults, shear zones, and associated fracture systems play a key role in providing a physical pathway connecting metal sources and the sites of mineral precipitation. LÄS MER

7. 30. Tree-limit ecotonal response to Holocene climate change in the Scandes Mountains of west-central Sweden

   Författare :Jonas Bergman; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tree-limit ecotone; alpine vegetation; tephrochronology; peat humification; plant macrofossils; Palaeobotany; fylogeni; Paleobotanik; palynology; phylogeny; palynologi; Geologi; Geology; pedology; geomorphology; Physical geography; klimatologi; geomorfologi; climatology; Fysisk geografi; cartography; Holocene climate; palaeoecology; marklära; kartografi; pollen influx;

   Sammanfattning : The aim of this thesis was to reconstruct the Holocene vegetational and climatic development in the Sylarna-Storulvån area, western Jämtland, in the central Scandes Mountains. Temporal trends and fluctuations in the elevation and vegetational character of the tree-limit ecotone were studied mainly by means of pollen and plant macrofossil analysis of two lake sediment sequences (Lakes Stentjärn and Spåime), located above the present-day tree-limit. LÄS MER