Glaciotectonic deformation of till-covered glaciofluvial deposits in Oulu region, Finland

Sedimentary sequences in Isoniemi and Hangaskangas in the Oulu area of Finland have been studied using conventional sedimentological techniques including structural and clast-fabric measurements on fold and fault structures and till units. Four different facies wereidentified from the sequence in the Isoniemi area and three in the Hangaskangas area. In the Isoniemi area, the measurements of glaciotectonic deformation and till clast-fabric analyses can be related to the ice movement from the south-west and the subsequent icefront oscillation from the north-west. These ice movement phases are thought to have taken place during the Late Weichselian. In the Hangaskangas area, the south-western shear-stress direction crosscuts the sediment strata indicating that the latest ice movement came from that direction during the Late Weichselian. However, there is also indication of an earlier shear-stress in the Hangaskangas area indicating the north-western ice movement. The age of this ice movement phase is thought to be older than the Late-Weichselian.