A new record of the Cenomanian–Turonian transgression preserved in the Ikorfat Fault zone, Nuussuaq Basin, West Greenland

Abstract

The Ikorfat Fault zone in northern Nuussuaq, Central West Greenland, has preserved a hitherto unknown succession of Upper Cretaceous marine mudstones referred to the Itilli Formation, which have been removed by erosion on the footwall block and buried deeply below sea-level on the hanging-wall block. Outcrops in the fault zone provide new data on sedimentology, palynology, stable carbon isotopes and organic geochemistry in the lower part of the Itilli Formation. A new, detailed geological map of the study area is based on digital photogrammetry. Marine organic walled dinoflagellate cysts (dinocysts) demonstrate a late Cenomanian–Turonian age, coeval with the Oceanic Anoxic Event 2 (OAE2) and link the Nuussuaq Basin with the Baffin Bay and Sverdrup Basins. The Ikorfat Fault zone is part of the eastern boundary fault of the Nuussuaq Basin. Lower Campanian listric faults truncate the footwall block. Subsidence along steep normal faults continued during deposition of the volcanic Vaigat Formation of Danian to Selandian age. The downthrow of the hanging-wall block was around 2.5 km.