Disputas og prøveforelesning er i Auditorium 1 i Geologibygningen. I noen tilfeller vil prøveforelesning og disputas være mulig å delta på digitalt, i så fall blir det lagt ut en lenke til Zoom.
Prøveforelesning
Onsdag 27. august, 10:15-11:00, Aud 2, Geologibygningen:
Geophysical, geochemical and petrological evidence for ridge-plume interactions: the case of the Reykjanes Ridge south of Iceland
Kreeringssammendrag
Dype mantelstrømmer og gamle riftsoner på havbunnen kan påvirke hvor og hvordan undersjøiske vulkaner dannes, selv langt fra tektoniske plategrenser der jordskorpeplater møtes. I sin doktorgradsavhandling har Lea Beloša undersøkt hvordan strukturer som riftsonen ved Jan Mayen kan kontrollere magmastrømmer og føre til uventet vulkanisme, slik som ved den undersjøiske fjelltoppen Vesteris (Vesterisbanken Seamount) i Nordøst-Atlanteren, mellom Grønland og Norge,
Hovedfunn
Populærvitenskapelig artikkel om Belosas avhandling:
Intraplate Volcanism in the Northeast Atlantic and the role of fracture zone-plume interactions
Deep mantle processes and ancient fractures in the ocean crust can control where and how underwater volcanoes form, sometimes in unexpected regions, such as oceanic basins far from active plate boundaries. In her docorat thesis, Lea Beloša has explored these formation processes and fracture zone using a combination of geophysical imaging, geochemical analysis, and crystal-scale mineral studies. The study examines both regional and local processes driving intraplate volcanism.
Focusing on large-scale features such as fracture zones and volcanic rocks from the underwater Vesteris Seamount, the doctoral thesis by Beloša demonstrates that structures like the Jan Mayen Fracture Zone are not just tectonic scars; they actively influence where magma is generated and how it can be transported far from hotspots. High-resolution mapping revealed links between crustal thickening and unexpected volcanic features across the Northeast Atlantic seafloor.
Geochemical analyses from samples from the seabed show that Vesteris Seamount’s magma source is mostly depleted mantle, enriched by recycled material likely introduced through lateral flow from the Iceland plume. Isotopic signatures indicate contributions from ancient mantle domains. Crystal-scale evidence reveals a vertically connected system of magma storage, with magma rising rapidly from depths of up to 30 km.
These findings improve our understanding of how deep Earth processes interact with tectonic structures to shape the ocean floor and control future volcanic activity.
Foto og annen informasjon:
Pressefoto: Lea Beloša, portrett; 1000px. Foto: Privat
