Faunal and floral distribution, biostratigraphy, cyclostratigraphy and magnetostratigraphy of the T/J boundary

• Autorzy: Michalík J. , Soták J. , Ruckwied K. , Götz A. , Grabowski J.
• Konferencja: International Congress on the Jurassic System (7 ; 06-18.09.2006 ; Kraków, Poland)
• Języki publikacji: EN

Abstrakty

EN

The Rhaetian and Hettangian sequence in the Zliechov Basin, Western Carpathians, comprises records of several environmental crises which could contributed to the global Triassic/Jurassic Boundary Events. The Upper Triassic Fatra Formation is characterized by bioclastic limestones and fine-grained clastics overlain by dark claystones with intercalated sandstones (Cardinia Sandstein) of the Kopieniec Formation. The diversity of benthic fauna decreased at the base of the "Transition Beds" - the uppermost member of the Fatra Formation. The fauna comprises important index forms of bivalve molluscs (Chlamys valoniensis), corals, brachiopods (Austrirhynchia cornigera) and foraminifers (Triasina hantkeni, etc.). The palynofacies of the entire succession is dominated by terrestrial components and by high amount of phytoclasts. The few marine organic particles indicate a very shallow marine depositional environment. The palynomorph assemblage of the Fatra Formation is characterized by numerous specimens of Ricciisporites tuberculatus. The marine fraction of the lower part of the section is dominated by the dinoflagellate cyst Rhaetogonyaulax rhaetica. The palynomorph assemblage of the Kopieniec Formation is characterized by a significant increase of trilete laevigate spores, mainly Deltoispora spp. and Concavisporites spp. The dinoflagellate cyst Dapcodinium priscum replaces Rhaetogonyaulax rhaetica in the marine fraction. These changes may be caused by a regression at the Triassic/Jurassic boundary and by an important fresh water input. The boundary between the Fatra and the Kopieniec formations is sharp, denoted by sudden termination of carbonate sedimentation followed by non-carbonate Boundary Clay of the Kopieniec Formation. Magnetostratigraphic record is in procession, it is hampered by complicated pattern of geomagnetic reversals at the end of the Triassic and at the beginning of the Jurassic period.

Słowa kluczowe

EN

Rhaetian; T/J boundary; Western Carpathians; biostratigraphy; palaeobiogeography; stratigraphy; cyclostratigraphy; magnetostratigraphy

• Wydawca: Państwowy Instytut Geologiczny - Państwowy Instytut Badawczy
• Czasopismo: Volumina Jurassica
• Rocznik: 2006
• Tom: Vol. 4, no. 1
• Strony: 292--292

Twórcy

autor

Michalík J.

autor

Soták J.

autor

Ruckwied K.

autor

Götz A.

autor

Grabowski J.

• Geological Institute, Slovak Academy of Science, Dúbravská 9, P.O. Box 106, SK-84005 Bratislava, Slovakia,