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

STRATIGRAPHY AND DEPOSITIONAL ENVIRONMENTS The Jurassic sequence including the Pliensbachian is cropping out in a SW-NE trending belt in the middle part of the Bakony Mts. The location of bivalve-bearing sections and outcrops is shown in Fig. 1. Most of the exposures were artificial trenches. Their zonal subdivision, based on the works of GÉCZY (1971a, 1971b, 1972, 1974, 1976) and DOMMERGUES et al. (1983), is given in Fig. 2. Fig. 1. Pliensbachian bivalve localities in the Bakony Mts. 1: Szentgál, Tűzköves Hill and Gombáspuszta; 2: Hárskút, Kisnyerges Ravine; 3: Hárskút, Közöskúti Ravine; 4: Lókút, Fenyves-kút; 5: Eplény, former Mn-ore mine; 6: Lókút, Kericser Hill; 7: Lókút Hill; 8: Lókút, Kávás Hill; 9: Lókút, Középhát and Büdöskút; 10: Borzavár, Bocskor Hill; 11: Tés, Hamuháza; 12: Bakonycsernye, Tüzköves Ravine The Pliensbachian is represented by various successions of marine sediments, predominantly carbonates. According to the facies model proposed by GALÁCZ & VÖRÖS (1972) and VÖRÖS (1974, 1986, 1995), tops of submarine highs (seamounts), their slopes and feet, as well as basins between them were the main sedimentary environments. Most of the Pliensbachian rocks ean easily be fitted into this model. As compared to the "true" Jurassic basins, such as the Lombardián basin of the Southern Alps, however, the Bakony should be rather considered as a large seamount or submarine plateau. Each environment can be characterized by distinctive stratigraphie features and lithologies. Condensed sequences of massive to well-bedded, ferro-manganese-oxyde-rich biomicrites with frequent stratigraphie gaps and hardgrounds are interpreted as accumulated on top areas and in fissures of seamounts. Petrography and genesis of biosparites belonging to the Hierlatz Limestone formation were discussed in detail by