International Field Workshop on 'The Triassic of eastern France'

supported by the occurrence of bioturbation. The interbedded aeolian sand sheets, sometimes bioturbated,
and mud-crack structures indicate frequent subaerial exposure. The occurrence of sheet flood deposits,
aeolian sand-sheets and mudcracks in fine-grained sediments point to an ephemeral hydrologically-closed
lake formed under arid condition (Rogers and Astin, 1991). This facies association characterizes fluvio-
aeolian overbank environments.
Stop 4.5 - Niedersteinbach (forest trail): Permian (‘French Lower Buntsandstein’
(‘Grès d'Annweiler’ Fm.) on Rotliegends)
In this outcrop (See p. 7 for location), just at the western end of Niedersteinbach, the 'French Lower
Buntsandstein' is represented by the ‘Grès d’Annweiler’. In the region of the eponyme locality, north of
Wissembourg, the basal part of the formation yielded a marine malacofauna typical of the Zechstein I; thus
the 'French Lower Buntsandstein' is Permian in age. The lithofacies are very similar to those of the ‘Couches
intermédiaires’.
Stop 4.6 - Fleckenstein Castle: ‘Grès d'Annweiler’ Fm. and Trifels facies of the ‘Grès
vosgien’ Fm
The lowermost fluvial conglomerate facies association is located at the base of the Lower Triassic,
characterizing the ‘Conglomérat basal’ Formation. This formation, well observed on well-logs, overlies the
basement and is located in the western part of the basin. It is diachronous and represents the landward
equivalent of the ‘Grès vosgiens’ Formation (See stop 1.4). It corresponds to more proximal braided-river
deposits, that evolve in space (laterally, i.e. eastwards) and time (vertically) into braided river of the ‘Grès
vosgiens’ Formation.
In this outcrops (See p. 7 for location, Fig. 48), the ‘Grès vosgiens’ Formation shows typical fluvial
facies (see Stop 1.1) and in its upper part aeolian deposits (Fig. 49) well preserved between to fluvial episods
(see stop 1.4 for facies description).
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