In the Late Triassic, an extremely large carbonate platform system (Dachstein-type platforms) developed on the margin of the Neotethys. On the wide inner platform cyclic peritidal, lagoonal successions were deposited. In the Transdanubian Range (Hungary), the lower part of the 1.5-2-km-thick cyclic succession (Upper Tuvalian-mid-Norian) is pervasively dolomitised, the upper part (Upper Norian-Rhaetian) is non-dolomitised; there is a transitional interval between them made up of partially dolomitised cycles. The peritidal-lagoonal cycles are commonly bounded by well-developed disconformity surfaces reflecting subaerial erosion that punctuated the marine carbonate accumulation. Truncation of the cycles was preceded by pervasive cementation of the previously deposited cycle. In the early stage of the platform evolution, tidal flat dolomitisation under semi-and conditions led to the consolidation of the previously deposited sediments. The truncation surfaces were commonly covered by dolocretes. During the more humid Late Norian-Rhaetian period, the early cementation was followed by karstification, accumulation of wind-blown dust and pedogenesis. Erosion during regularly recurring subaerial exposure that commonly reached the previously deposited subtidal beds suggests eustatic control of the cyclicity and supports the application of an allocyclic model, even if the Milankovitch signal is imperfect.
