Cyclic sedimentation across the Permian-Triassic boundary (Central Taurides, Turkey)

The best preserved Permian - Triassic boundary beds in Turkey are found in the Hadim region of the central Taurides. The succession is exposed in one of the allochthonous units of the Tauride Belt, the Aladag Unit, whose stratigraphy includes beds ranging from the Devonian to the Cretaceous systems. In the Aladag Unit, the Permian - Triassic boundary beds are entirely composed of carbonates. The Permian portion of these beds belongs to the Paradagmarita Zone, whereas the lowermost Triassic contains the Lower Griesbachian marker Rectocornuspira kalhori. The uppermost Permian carbonates, composed of meter-scale upward shallowing subtidal cycles, are characterized by oolitic limestones of regressive character at the top and are overlain sharply by Lower Triassic stromatolites. Cyclic Upper Permian carbonates are interpreted as highstand systems tract deposits of the last third-order sequence of the Permian System. The Permian - Triassic boundary is an unconformity corresponding to both erosional and non-depositional hiatuses. The gap at the Permian - Triassic boundary partially corresponds to the shelf-margin systems tract and partly to the transgressive systems tract of the overlying third-order sequence. Stromatolites are interpreted as transgressive systems tract deposits