Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 21. 2003. (Budapest, 2003)

FRAGMENTA PALAEONTOLOGICA HUNGARICA 21, BUDAPEST, 2003 Early Jurassic fauna and facies of the Schafberg area (Salzkammergut, Austria) by Attila VÖRÖS, János SZABÓ, Alfréd DULAI, István SZENTÉ, Oskar EBLI «Sc Harald LOBITZER Abstract — In order of a complex reexamination of the Jurassic faunas of the Schafberg and closely connected area, the authors carried out new collecing and sampling. The studied area contains localities of classical palaeontological monographs, based on fossils of the Lower Liassic Mierlatz Formation and some other associated limestones. During the field work we attempted to locate the classical sites but most of the exposures are new. Characteristic megafossils are the brachiopods but bivalves and gastropods are also found. Beside notices on the microfacies and microfossils, the identified species of the faunas are listed below, and, some palaeontological remarks are added to most of the listed species. The faunal lists are partly completed with museum materials. Keywords — Early Jurassic, microfacies, bivalves, gastropods, brachiopods VÖRÖS, A., SZABÓ, J., DULAI, A., SZENTÉ, I., EBLI, O. & LOBITZER, H. (2003): Early Jurassic fauna and facies of the Schafberg area (Salzkammergut, Austria). — Fragmenta Palaeontologica Hungarica, 21: 51—82. Introduction Mt Schafberg belongs to the classical areas of Liassic research in the Northern Calcareous Alps and several monographies dating back to the 19

th century deal with the rich mega- and microfauna from various lithologies. The first comprehensive description of the rich megafauna of the Hierlatz Limestone we owe to HAUER (1853, 1855) who already mentioned ammonites and brachiopods in the light reddish and whitish limestones in the higher regions of Schafberg. OPPEL (1861), BlTTNER (1893) and BÖSE (1877) dealt with the brachiopod fauna in more details, while GEYER (1893) described the ammonites and STOLICZKA (1861) studied the gastropods and the bivalves. OPPEL assumed, based on findings of ammonites, that the Hierlatz Limestone of the Schafberg is of Lower Liassic age, while STOLICZKA'S studies pointed to Middle Liassic. In 1862 MOJSISOVICS paid a short visit to Mt Schafberg and argued that OPPEL is right in the age of the ammonitebearing basal dark red limestone. However, he regarded the higher part of the gastropod-bearing dark red limestone and the overlying brachiopod-dominated Hierlatz Limestone s.s. as Middle Liassic. STUR (1871) reports a faunule consisting of ammonites, bivalves and brachiopods from bright red limestones of the Grünsee locality. In his classical paper on the facies differentiarion of various Liassic limestones of the Northern Calcareous Alps, WÄHNER (1886) considered the light-red cephalopod-rich limestones of the "Hinter-Schafberg" an equivalent of the horizon of Amaltheus margaritatus. From facies point of view WÄHNER regarded these variegated cephalopod limestones as transitional development between the brachiopod-crinoid-gastropod-rich Hierlatz Limestone and the true Adnet Limestone. The sponges, radiolarians and foraminifers of the "Uas-Kieselkalk" were described by DUNIKOWSKI (1882). On the occasion of the IXth International Geological Congress in Vienna in the year 1903, WÄHNER summarized his rich knowledge on that region in an excursion guide booklet of the Schafberg. SPENGLER (1911), who had been WÄHNER'S student, published the most comprehensive description of the geology of Schafberg, situated within the "SchafbergTirolikum" tectonic unit. SPENGLER initiated also the first microfacies study of the Schafberg region by LEISCHNER (1969). From the tectonic point of view, also the paper by HAHN (1913) is important. The complex tectonic situation of Mt Schafberg is well explained by PLÖCHINGER (1973). In principle, the upper part of Schafberg is represented by a synclinc, which is overturned towards the North. Looking from the North to the northern wall of Mt Schafberg, we face Upper Jurassic radiolarite in the core of the syncline, which is underlain by red Middle Liassic Adnet type limestones and by Hierlatz limestone, which is well exposed also on the top of Mt Schafberg. The area may be divided into two main tectonosedimentary units, separated by a large-scale overthrust at the northern foot of the Schafberg, recognized and named by SPENGLER (1911) as "Grünsee Überschiebung" or "Grünseescherfläche" (PLÖCHINGER 1973). The upper unit forms the bulk of the Schafberg, consisting chiefly of Hierlatz limestones of extremely big thickness and grey, siliceous limestones of Lower Jurassic (mainly Sinemurian) age. The Hierlatz limestones are exposed on the top and on the southern slope of Schafberg in the form of thick, not well-defined beds dipping roughly concordant with the slope. It represents the "bed-like" type of VÖRÖS (1991) and can be interpreted as a wide belt of submarine, biodetrital talus of 200-300 m thickness. The source area of the biodetrital material may be sought toward the North, near or beyond die peak region of Schafberg, whereas the interfingering with more distal, basin sediments can be found nearly one km far to the South (e. g. at Schafbergalpe). The lower unit is exposed in a narrow belt along the northern foot of Schafberg and consists of Upper Triassic