Middle carboniferous marine transgression, Bjørnøya, Svalbard: facies sequences from an interplay of sea level changes and tectonics

Abstract

AbstractThe Svalbard Platform, in middle Carboniferous time, was dominated by a series of NNW‐SSE oriented, asymmetric rift basins. The Landnørdingsvika Formation represents the infill of one such basin in the Bjørnøya (Bear Island) area and consists of red beds deposited during a regional rise of sea level. The basin was filled mainly from the west and southwest across a Carboniferous fault zone, the West Bjørnøya. Fault, which bounded the deep edge of the basin.The basin succession is dominated by floodplain and coastal plain deposits in its lower part and fanglomerates interbedded with shallow marine clastics and carbonates in its upper part. The marine facies gradually increase in volume upwards and culminate in the overlying, carbonate‐dominated Kapp Kåre Formation (Moscovian). This continental‐marine transition, which has also been identified in the other Svalbard basins, thus reflects an important middie‐late Palaeozoic transgression. Analysis of the facies sequences shows that there are repeated submergence‐emergence events which are superimposed on the longer term transition. These are interpreted in terms of repeated basin floor tilting and sinking against the upland block.