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.

Intense and widespread seismicity during the end-Triassic mass extinction due to emplacement of a large igneous province

Abstract: Multiple levels of earthquake-induced soft-sediment deformations (seismites) are concentrated in the end-Triassic mass extinction interval across Europe. The repetitive nature of the seismites rules out an origin by an extraterrestrial impact. Instead, this intense seismic activity is linked to the formation of the Central Atlantic magmatic province (CAMP). By the earliest Jurassic the seismic activity had ceased, while extrusive volcanism still continued and biotic recovery was on its way. This suggests that magmatic intrusions into sedimentary strata during early stages of CAMP formation caused emission of gases (SO 2 , halocarbons, polycyclic aromatic hydrocarbons) that may have played a major part in the biotic crisis.

Dating of Late Quaternary faulting in northern Sweden

Abstract: Fault scarps, interpreted as post- or late-glacial in age, occur in northern Sweden and adjacent parts of Finland and Norway. In the Lansjarv area in northern Sweden, attempts have been made to date fault displacement relative to the glacial and postglacial stratigraphy by trenching across fault scarps. It is shown that the faulting occurred soon after the local deglaciation some 9000 years ago with no signs of movements since. The faulting appears to have been associated with violent earthquakes, because landslides and soil deformation, interpreted to be seismically induced and dating from the same period as the faulting, are frequently found in the area.

Reactive monazite and robust zircon growth in diatexites and leucogranites from a hot, slowly cooled orogen: implications for the Palaeoproterozoic tectonic evolution of the central Fennoscandian Shield, Sweden

Abstract: Monazite in melt-producing, poly-metamorphic terranes can grow, dissolve or reprecipitate at different stages during orogenic evolution particularly in hot, slowly cooling orogens such as the Svecofennian. Owing to the high heat flow in such orogens, small variations in pressure, temperature or deformation intensity may promote a mineral reaction. Monazite in diatexites and leucogranites from two Svecofennian domains yields older, coeval and younger U–Pb SIMS and EMP ages than zircon from the same rock. As zircon precipitated during the melt-bearing stage, its U–Pb ages reflect the timing of peak metamorphism, which is associated with partial melting and leucogranite formation. In one of the domains, the Granite and Diatexite Belt, zircon ages range between 1.87 and 1.86 Ga, whereas monazite yields two distinct double peaks at 1.87–1.86 and 1.82–1.80 Ga. The younger double peak is related to monazite growth or reprecipitation during subsolidus conditions associated with deformation along late-orogenic shear zones. Magmatic monazite in leucogranite records systematic variations in composition and age during growth that can be directly linked to Th/U ratios and preferential growth sites of zircon, reflecting the transition from melt to melt crystallisation of the magma. In the adjacent Ljusdal Domain, peak metamorphism in amphibolite facies occurred at 1.83–1.82 Ga as given by both zircon and monazite chronology. Pre-partial melting, 1.85 Ga contact metamorphic monazite is preserved, in spite of the high-grade overprint. By combining structural analysis, petrography and monazite and zircon geochronology, a metamorphic terrane boundary has been identified. It is concluded that the boundary formed by crustal shortening accommodated by major thrusting.