Climate change at the Triassic/Jurassic boundary in the northwestern Tethyan realm, inferred from sections in the Tatra Mountains (Slovakia)

Abstract

Sedimentological, palynological, clay mineralogical and carbon isotope studies were carried out on the Triassic/Jurassic (T/J) boundary interval in the Nw Tethyan realm. The analyses are based on two sections in the Slovakian Tatra Mountains (western Carpathians): the Široký Žlab section in the Medodoly Valley and the furkaska section above the Juránova Valley. Clay mineralogical analysis suggests an increasing intensity of chemical weathering in the hinterland due to increasing humidity. The palynological data do not allow the inference of a major T/J boundary mass extinction event. The observed striking increase in spores points instead to sudden climatic change, interpreted as a result of distant volcanic activity associated with the onset of rifting of Pangea. The d13Corg excursion across the T/J boundary follows the globally documented perturbation of the carbon cycle during this period. it may be used for a more precise regional and global correlation.