En glacialgeologisk studie av morän och moränfyllda sprickor i underliggande sandursediment, Örsjö, Skåne

Sammanfattning: The late quaternary deposits at Örsjö, 2 km east of the village Skurup, south Skåne consist of three main units. Direct above the bedrock there is a diamicton correlated to Allarp till according to Lagerlund (1980). The seeond unit, the so called Örsjöbeds, consist of up to 40 meter sorted sediments in general coarsening upwards. The unit is described as a Sandur deposit by earlier workers (Lindberg 1973, Lagerlund 1980 and Daniel 1992). The third unit consist of a complex till sequence. At the locality two spectacular tectonic structures have been observed. One large normal fault and a 10 - 15 meter wide and at least l km long fracture with unknown depth. The cracking is cut into the Sandur deposit and filled with material mainly from the overlaying till sequence. This paper concentrates on the contact between the Sandur deposit and overlaying till sequence and the sedimentology of the till sequence and the two tectonic structures. The main task is to describe the sediments in the fracture and to discuss the evolution of the fracture. The contact between the Sandur deposit and the sediments filling the fracture form a very steep angle (60°-80°) wich is 30°-40° more than the normal fall angle for the Sandur sediments. Because of that the Sandur sediments must have had some kind of support during the opening of the fracture. Otherwise te Sandur sediments would have colapsed. The fabric data indicates one ice flow direction and the tectonic structures indicates another direction at the same stratigraphical level, wich leads to the conclusion that the crack was not formed by glacial tectonics.