High-resolution organic carbon–isotope stratigraphy of the Middle Jurassic–Lower Cretaceous Agardhfjellet Formation of central Spitsbergen, Svalbard

We present the first complete organic carbon–isotope curve from the Agardhfjellet Formation, central Spitsbergen (Svalbard). Samples from two drill cores (DH2 and DH5R) were analysed for δ13Corg, total organic carbon (TOC) and Rock Eval. Rock Eval, litho- and biostratigraphy demonstrate a similar development in the two cores, allowing construction of a composite δ13Corg curve covering the Bathonian to lowermost Cretaceous. There are only weak correlations between Rock Eval parameters and δ13Corg, suggesting the isotopic signal is not mainly controlled by type of kerogen/maturation but rather reflects regional or global environmental changes. The carbon–isotope curves from the cores can be correlated with previously published curves from outcrops of the Slottsmøya Member and with more distant localities in the Barents Sea, Siberia, Great Britain and the Atlantic. Features in common with other published curves include a Callovian–Oxfordian positive excursion, a Kimmeridgian–Middle Volgian negative trend and a Middle Volgian negative excursion. These correlations allow refinement chronostratigraphy of the Jurassic of Svalbard.