Stable isotopes and geochemistry of a Campanian–Maastrichtian pelagic succession, Mudurnu–Göynük Basin, NW Turkey: Implications for palaeoceanography, palaeoclimate and sea-level fluctuations

Abstract

This study focuses on the palaeoclimatic evolution and relative sea-level fluctuations of the northern branch of NeoTethys during the late Campanian–early Danian. The studied succession (İsmailler Section) is located in the Mudurnu–Göynük Basin, NW Turkey and dominated by apparently continuous pelagic muddy deposits. Stable isotopic and elemental compositions of the mudrocks are investigated in order to evaluate the palaeoceanographic conditions as well as broad tectonic reconstruction of the basin. The mudrock geochemistry suggests a tectonic reorganization during late Campanian as reflected by a distinct shift from felsic to mafic sediment provenance. In the İsmailler Section, five δ13C events are identified; four or which are well correlatable with major events in other records around the world, such as the late Campanian Event (LCE), Campanian–Maastrictian Boundary (CMB) and the late Maastrichtian Event (LME). The relative sea-level variations in the basin typically match both short- and long-term global sea-level fluctuations. The remaining globally uncorrelatable δ13C event does coincide with tectonic uplift and the abrupt negative δ13C shift, and is inferred to be the result of regional factors. The dominance of worldwide events in the records of the relatively restricted ocean branch reflects the strength of global factors.