INTEGRATED STRATIGRAPHY OF THE MIDDLE-UPPER JURASSIC OF THE KRIZNA NAPPE, TATRA MOUNTAINS

Middle-Upper Jurassic pelagic carbonates and radiolarites were studied in the Krizna Nappe of the Tatra Mountains (Central Western Carpathians, southern Poland and north ern Slovakia). A carbon isotope stratigraphy of these deposits was combined with biostratigraphy, based on radiolarians, calcareous dinoflagellates and calpionellids. In the High Tatra and Belianske Tatra Mountains, the Bajocian and part of the Bathonian are rep resented by a thick succession of spotted lime stones and grey nodular lime stones, while in the West ern Tatra Mountains by relatively thin Bositra-crinoidal lime stones. These deposits are re fer able to a deeper basin and a pelagic carbon ate plat form, respectively. The various carbon ate facies are followed by deep-water biosiliceous facies, namely radiolarites and radiolarian-bearing lime stones of Late Bathonian-early Late Kimmeridgian age. These facies pass into Upper Kimmeridgian-Lower Tithonian pelagic carbonates with abundant Saccocoma sp. The bulk-carbonate isotope composition of the carbonate-siliceous deposits shows positive and negative delta C-13 excursions and shifts in the Early Bajocian, Late Bajocian, Early Bathonian, Late Bathonian, Late Callovian, Middle Oxfordian and Late Kimmeridgian. Addition ally, the delta C-13 curves studied show a pronounced increasing trend in the Callovian and a steadily decreasing trend in the Oxfordian-Early Tithonian. These cor re late with the trends known from the Tethyan region. The on set of Late Bathonian radiolarite sedi mentation is marked by a decreasing trend in delta C-13. In creased delta C-13 values in the Late Callovian, Middle Oxfordian and Late Kimmeridgian (Moluccana Zone) cor respond with enhanced radiolarian production. A significant in crease in CaCO3 con tent is recorded just above the Late Callovian delta C-13 excursion, which coincides with a transition from green to variegated radiolarites.