Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 18. 1996. (Budapest, 1996)

The Middle Triassic paleotectonic and sedimentary evolution of the Balaton area was shortly analysed and summarized by BUDAI & VÖRÖS (1992). Two submarine elevations (active carbonate platforms, then pelagic plateaus) and an intervening system of basins are clearly shown on their paleogeographic maps. The six sections studied here from paleoecological point of view will be shortly presented in the following. (For their location see Fig. 1) (1) Szentantalfa. Here the uppermost part of the Anisian carbonate platform limestone (Tagyon Limestone) is exposed and its sharply truncated top surface is capped by a thin (1.5 m) sequence of brownish-yellow to purplish-red crinoidal and tuffitic, ammonitic limestone beds. These layers are followed by tuffitic clays. The most frequent elements of the rich ammonoid fauna (more than 800 specimens, 15 taxa) belong to Semiornites, Paraceratites,Asseretoceras, Lardaroceras and Flexoptychites

. The sequence was deposited on the top of a pelagic plateau and represents the Camunum and Pseudohungaricum subzones of the Upper Anisian Trinodosus Zone. (2) Mencshely. The lowermost beds of this section belong to the Anisian Felsöörs Formation (grey limestone beds with clay intercalations). This is followed by ash-grey tuffites of the Buchenstein Formation in about 4 m thickness, containing a few, thin (810 cm) yellow and grey cherty limestone intercalations. The higher part of the tuffitic sequence becomes pinkish and passes into reddish-bown clay with limestone lumps. These crinoidal, tuffitic limestone lumps yielded a very rich ammonoid fauna. With gradually decreasing amount of clay, massive crinoidal limestone beds appear. The uppermost member of the exposed sequence is light-coloured micritic limestone. The ammonoid fauna is extremely rich (1200 specimens, 27 taxa); the most diagnostic genera are: Kellner-ites, Norites, Longobar

dites, Kellnerites, Hungarites, Reitziites, Aplococeras, Parakellnerites, Halilucites, Stoppaniceras, Flexoptychites, Discoptychites and Proarcestes. The sequence accumulated in a basin of low sedimentary rate and represents the Felsoeoersensis to Avisianum subzones of the Lower Ladinian Reitzi Zone. (3) Vászoly. From the numerous localities of the Öreg-hegy (Hill) between the villages Vászoly and Pécsely, the section "P-ll/a" has been studied in detail. Here the Anisian Megyehegy Dolomite is followed by yellow tuffites alternating with limestone and massive dolomite layers in 2 m thickness. Above this, the yellowish tuffites become dominant and contain sporadic calcareous lumps. The higher part of this 3 m thick sequence consists of tuffitic clay containing big blocks of yellow crinoidal limestone with plenty of ammonites. The exposed sequence is terminated with massive beds of light-coloured micritic limestone (Vászoly Limestone). (More detailed descriptions of the section are published in VÖRÖS & PÁLFY 1989 and KOVÁCS et al. 1990.) The rich ammonoid fauna (more than 800 specimens, 22 taxa) consists of the following main elements: Asseretoceras, Lardaroceras, Megaceratites, Longobar dites, Parakellne-ites, Hungarites, Reitziites, Stoppaniceras, Ticinites, Halilucites and Flexoptychites. The sequence was deposited on the top of a submerged platform (pelagic plateau) and represents the uppermost part of the Anisian Trinodosus Zone and the Lower Ladinian Reitzi Zone (Camunum to Avisianum subzones).