Porifera-microbialites of the Lower Liassic (Northern Calcareous ...

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Fig. 1. Simplified paleogeographical reconstruction of the northwestern Tethys shelf in Upper Triassic times
and cross-section through Rhaetian facies belts of the Upper Triassic Carbonate Platform (Northern Calcareous
Alps). Modified from Smith et al. (1994), Krystyn and Lein (1996) and Gawlick (2000).
between form the main part of the present Northern Calcareous Alps. Sections of the Triassic top
as well as relics of the subsequent Liassic sediments are exposed in several regions. The latter
are formed by either grey deposits of basinal settings or red-colored limestones from deep water
rises, both comprise numerous local facies types described by just as many different names
(“Adneter Schnöll”, “Hierlatzkalk”, “Fleckenkalk”, “Scheibelbergkalk”, “Lias-Spongienkalk”,
“Lias-Basiskalk”, “Allgäuschichten”, “Kirchsteinkalk”, and many others, sensu Böhm 1992).
Due to only minor tectonic movements, the Osterhorn block anticline (southeast of Salzburg)
and adjacent areas allow to study large cross-sections of the Upper Triassic Carbonate Platform
(e.g. Piller and Lobitzer 1979; Gawlick 2000). Several small outcrops expose the crucial T-J
interval, thus most visited localities are spread over this region (Fig. 2). Breccias, sliding masses,