Geological Survey of Sweden

About: Geological Survey of Sweden is a government organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Metamorphism & Zircon. The organization has 316 authors who have published 671 publications receiving 18333 citations. The organization is also known as: Sveriges Geologiska Undersökning.

Seismic LAB or LID? The Baltic Shield case

Abstract: . The problem of the asthenosphere for old Precambrian cratons, including East European Craton and its part – the Baltic Shield, is still discussed. To study the seismic lithosphere-asthenosphere boundary (LAB) beneath the Baltic Shield we used records of 9 local events with magnitudes in the range 2.7–5.9. The relatively big number of seismic stations in the Baltic Shield with a station spacing of 30–100 km permits for relatively dense recordings, and is sufficient in lithospheric scale. For modelling of the lower lithosphere and asthenosphere, the original data were corrected for topography and the Moho depth for each event and each station location, using a reference model with a 46 km thick crust. Observed P and S arrivals are significantly earlier than those predicted by the iasp91 model, which clearly indicates that lithospheric P and S velocities beneath the Baltic Shield are higher than in the global iasp91 model. For two northern events at Spitsbergen and Novaya Zemlya we observe a low velocity layer, 60–70 km thick asthenosphere, and the LAB beneath Barents Sea was found at depth of about 200 km. Sections for other events show continous first arrivals of P waves with no evidence for "shadow zone" in the whole range of registration, which could be interpreted as absence of asthenosphere beneath the central part of the Baltic Shield, or that LAB in this area occurs deeper (>200 km). The relatively thin low velocity layer found beneath southern Sweden, 15 km below the Moho, could be interpreted as small scale lithospheric inhomogeneities, rather than asthenosphere. Differentiation of the lid velocity beneath the Baltic Shield could be interpreted as regional inhomogeneity. It could also be interpreted as anisotropy of the Baltic Shield lithosphere, with fast velocity close to the east-west direction, and slow velocity close to the south-north direction.

The deglaciation of Scandinavia later than 10,000 B.P.: The 1979 Uppsala Symposium

Abstract: The 1978 Uppsala Symposium was organized as a geste d'honneur to the memory of Otto Torell and his Ice-Age Theory, published a little more than a hundred years ago. The Symposium opened with a lecture on the development of the Ice-Age Theory, then four regional surveys of our present knowledge of the deglaciation pattern and chronology yielded new and somewhat controversial ideas about the melting of the Scandinavian Continental Ice, and more than forty individual research reports showed the dynamic scientific situation in Quaternary Geology in Norden. The Symposium and this issue of Boreas form part of the joint Nordic activity within the IGCP project entitled ‘Quaternary Glaciations in the Northern Hemisphere’.