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Abstract
Chemical and structural data from the Småland-Blekinge Deformation Zone (SBDZ) in south-east Sweden are presented. Earlier published age determinations are included in the discussions. The Transscandinavian (TIB) granitoids immediately to the north of the SBDZ are characterised by anomalously low K/(K+Na+Ca) ratios compared to the majority of TIB granites. The generally more mafic Tving granitoids to the south of the SBDZ are mostly higher in K/(K+Na+Ca) than the neighbouring granites in the north. The TIB granitoids to the north of the SBDZ are characterised by a stronger increase in mafic components with decreasing SiO2 than in most other TIB granitoids. Results suggest differences in source rock compositions on either side of the SBDZ. This does not contradict suggestions of a former coherent terrane across the SBDZ but casts some doubts on them. Rocks in the SBDZ can in some cases be positively identified as deformed and metamorphosed equivalents of rocks occurring on either side of the SBDZ. However, counterparts of mafic rocks occurring within the SBDZ have not been identified in the neighbouring provinces. When approaching the SBDZ, the foliation becomes parallel with the SBDZ-strike direction, 110°. It is either vertical or dips steeply towards the SSW. Rocks occurring within the SBDZ are partly mylonitic, even suggestions of pseudotachylites are observed. Movements are principally vertical with an ‘up-to-the-south’ sense. A sinistral horizontal component is less well constrained and is interpreted to predate the vertical movements. The 1.45 Ga old granites essentially post-date the movements in the SBDZ.
