Early dolomitisation of Late Triassic platform carbonates in the Transdanubian Range (Hungary)

In the Late Triassic, a large carbonate platform system came into existence in the Transdanubian Range (TR) producing a 1.5- to 2-km-thick carbonate succession. The lower part of the platform carbonate series is made up of cyclic peritidal dolomite (Main Dolomite Formation), while the upper one consists of cyclic peritidal limestone (Dachstein Limestone Formation). However, there is a transitional member of remarkable thickness between them consisting of partially dolomitised limestone and calcitic dolomite. This study focuses on the transitional member where the process of early dolomitisation was halted at various stages. In the investigated sections the early dolomitisation was controlled by the climate and high-frequency sea-level oscillation, which led to periodic subaerial exposure of large areas and palaeo-hydrological conditions. Increasing humidity and gradual extension of the permanently inundated outer platform led to cessation of early dolomitisation in the Middle to Late Norian. (C) 2002 Elsevier Science B.V. All rights reserved.