Jurassic unconformities in the High-Tatric succession, Tatra Mountains, Poland

Abstract

The Triassic/Jurassic boundary interval and the Jurassic were periods of disintegration of Triassic carbonate platforms occupying the northern shelf of the Tethys. Record of these processes in the Alpine-Carpathian area is incomplete and contains a number of stratigraphical gaps. In the High-Tatric succession of the Tatra Mountains (Central Western Carpathians) stratigraphical gaps expressed by unconformity surfaces occur between the Middle Triassic and the Middle Jurassic. In particular areas, the Anisian is directly overlain by the Dudziniec Formation (Sinemurian-Bajocian), the Smolegowa Formation (Bajocian), the Krupianka Formation (Bathonian) or the Raptawicka Turnia Formation (Callovian-Hauterivian). The occurrence of Bajocian and Bathonian deposits is limited to isolated lenticular bodies or to infillings of neptunian dykes penetrating the Triassic. Spatial relations between particular Jurassic lithosomes and the occurrence of stratigraphical gaps between particular units allow to discern four main unconformities. In stratigraphical order these are: base of the Dudziniec Formation (erosional unconformity), base of the Smolegowa Formation (penacordance), base of the Krupianka Formation (erosional unconformity) and base of the Raptawicka Turnia Formation (drowning unconformity). Following episodes of erosion modified the previously developed unconformity surfaces, which resulted in complex modern architecture of the Triassic/Jurassic contact, as well as between particular Jurassic lithosomes.