The mid-Cretaceous world was characterised by unusually warm polar temperatures, extensive sea floor spreading and subsequent periods of major eustatic sea-level rise. At times volcanic outgassing increased the atmospheric pCO₂ and enhanced the terrestrial weathering. Weathering and rising sea level led to increased nutrient discharge and high organic productivity in the oceans. Associated increased decomposition of organic matter promoted the removal of oxygen, leading to anoxic conditions and elevated carbon burial in the sediments, a so called “oceanic anoxic event”.
One of the global oceanic anoxic events is the Cenomanian–Turonian boundary event (OAE2). The event is characterised by a major positive d¹³C excursion (ca. 2-4 ‰) in marine carbonate and both marine and terrestrial organic matter, which indicates that a major disturbance of the global carbon cycle occurred in the ocean and atmosphere system. The OAE2 is thought to be a widespread event and evidence has been found all over the world, mostly at low and mid palaeolatitudes in the proto-Atlantic. However, records of the OAE2 from high palaeolatitudes are still scarce.
The ongoing work will establish the chemostratigraphy in different depositional environments in the Nuussuaq Basin in West Greenland and investigate the palaeoceanography that prevailed during the OAE2 in the basin. Three localities in a proximal–distal transect through the Nuussuaq Basin will be investigated for d¹³C bulk from organic material and redox sensitive trace metals. These investigations should help to understand, if black shale deposition in the Nuussuaq Basin is linked to the widespread occurring OAE2.