Sökning: "tectonic development"

Visar resultat 21 - 24 av 24 avhandlingar innehållade orden tectonic development.

  1. 21. 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

  3. 22. The origin of the Ryllshyttan stratabound Zn-Pb-Ag-(Cu) + magnetite deposit, Garpenberg, Bergslagen, Sweden

    Författare :Nils Jansson; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Malmgeologi; Ore Geology;

    Sammanfattning : Ryllshyttan is a Palaeoproterozoic lower amphibolite-facies poly-metamorphosed stratabound Zn-Pb-Ag-(Cu) + magnetite deposit. It is located in the Garpenberg inlier of the Bergslagen mining district of southern Sweden and produced ~ 1 Mt sulphide ore and ~ 0.4 Mt magnetite ore from the early 16th century until 1944. LÄS MER

  4. 23. Study on the Earth’s Surface Mass Variations using Satellite Gravimetry Observations

    Författare :Hadi Amin; Mohammad Bagherbandi; Lars Sjöberg; Faramarz Nilfouroushan; Martin Horwath; Högskolan i Gävle; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geodetic reference system; geoid potential; global vertical datum; climate change; global warming; mass change; ice melting; sea-level change; remote sensing; satellite gravimetry; geodetiska referenssystem; geopotential; globala vertikala datum; klimatförändring; global uppvärmning; massförändring; issmältning; havsnivåförändring; fjärranalys; satellitgravimetri;

    Sammanfattning : Our complex planet is continuously undergoing temporal and spatial changes. In this context, ongoing processes in the Earth subsystems (geosphere, biosphere, cryosphere, hydrosphere, and atmosphere) cause changes in the gravity field of the Earth across a wide range of temporal and spatial scales. LÄS MER

  5. 24. U-Pb baddeleyite geochronology of Precambrian mafic dyke swarms and complexes in southern Africa - regional scale extensional events and the origin of the Bushveld Complex

    Författare :Johan Olsson; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; U-Pb TIMS geochronology; geochemistry; baddeleyite; mafic dyke swarms; mantle plume; Bushveld Complex; Kaapvaal Craton; Zimbabwe Craton; Archean; Proterozoic;

    Sammanfattning : Dolerite dykes are formed when iron- and magnesium-rich (mafic) mantle-derived magmas ascend through the lithosphere (upper part of the mantle) and crystallize as ‘hydro-fractures’ within the crust. Dykes may exist in great numbers to form dyke swarms (linear or radiating), which can be linked to time periods of continental break-up, or attempted break-up events, associated with voluminous volcanism. LÄS MER