Late Triassic-early Jurassic Carbon Isotope Stratigraphy And Cyclostratigraphy In North Tarim

High resolution stratigraphy correlation between marine and terrestrial sections has long been a major challenge.This study provides new field observations and organic carbon stable isotope records of the uppermost Triassic and lower Jurassic terrestrial successions of the Kuqa River section in the Tarim Basin.High-resolution organic carbon stable isotope records derived from wood fossils are calibrated within sporo-pollen assemblages.The carbon-isotope stratigraphic curves from the Kuqa River section are well correlated with those from the T/J GSSP section in Austria and other typical sections.Several negative and positive excursions in?¹³C curves coincide with the mass extinction interval at the end-Triassic extinction and T/J boundary,which can be used as a clue to define the isochronous T/J boundary in the terrestrial Kuqa River section with high resolution.Two?¹³C stratigraphic curves in the Kuqa River section are independently generated from two field samplings.The consistency of the two results shows the accuracy and repeatability of the study,which verifies the method of carbon-isotope stratigraphic sampling.Besides,cyclostratigraphy research is conducted by using of magnetic susceptibility proxy records covering the uppermost Triassic and lower Jurassic successions of the Kuqa River section and Haojiagou section.Based on the research,the durations of Rhaetian and Hettangian are estimated.Then,calculation and comparison on the interval between the end Triassic mass extinction and T-J boundary are carried out.