The Middle and Upper Permian Deposits in Gorski Kotar: Facts and Misconceptions

Abstract

The frequent occurrence of sandstones and other coarse-grained sedimentary rocks in Gorski Kotar indicates molasse type sedimentation as a consequence of the intensive erosion of all uplifted terrain in a tectonically active area. The indirect assumptions indicate that the age of the Gorski Kotar Palaeozoic complex, with the exception of a limited occurrence of Carboniferous clastic rocks, corresponds to the clastic Trogkofel beds. i.e. to Middle Permian. The absence of Upper Permian carbonate deposition in Gorski kotar indicates an interruption in sedimentation at the Permo-Triassic boundary, and a possible hiatus in the Upper Permian. In previous studies it was concluded that there is a continuous transition from the Permian (developed as the Groeden clastic facies) to the Lower Triassic shallow marine sedimentary rocks, although no such transitions occur in either the neighbouring areas (Velebit, Slovenia) nor in thc wider Southern Alps. The continuous transition exists only in the carbonatc successions (Upper Permian dolomite in the Velebit region and the Bellerophone formation in the Alps).