Organic carbon isotope variability across the P/Tr boundary in the Idrijca Valley section (Slovenia): A high resolution study
AbstractA systematic investigation of carbon isotopes in sedimentary organic carbon and microfacial analyses of the Idrijca Valley section were carried out using very narrow sampling intervals. The high-resolution results demonstrate the following characteristics: 1) Permian/Triassic boundary marked by the PTB layer lies within a 15 cm thick Tesero oolite horizon, 2) Two large negative δ13C sedimentary organic carbon anomalies exist, the first between 6 and 2 cm below and the second about the 4 cm above the PTB layer. The first, and most probably worldwide, negative organic carbon isotope shift in the topmost Permian coincides with an abrupt disappearance of the Upper Permian fauna. The isotopic results suggest that the Permian/Triassic boundary events were very sudden (less than or equal to 67 kyr.), and are most probably related to an abrupt general decrease in the δ13C value of ambient atmospheric CO2. The principal factors controlling δ13C of atmospheric CO2 were possibly related to volcanism together with degradation and oxidation of organic matter due to the terminal phase of the Upper Permian marine regression, rather than an instantaneous triggering event, such as an extraterrestrial body impact.
How to Cite
Dolenec, M., & Ogorelec, B. (2001). Organic carbon isotope variability across the P/Tr boundary in the Idrijca Valley section (Slovenia): A high resolution study . Geologija, 44(2), 331–340. https://doi.org/10.5474/geologija.2001.025