Late Oligocene Warming Event in the southern North Sea Basin: benthic foraminifera as paleotemperature proxies

The investigation of foraminiferal assemblages from a series of Oligocene borehole sections allowed paleoenvironment and paleoclimate reconstructions for the Rupelian and Chattian (Lower and Upper Oligocene) Stages in their type region, the southern North Sea Basin. A striking feature coinciding with the Rupelian-Chattian (R-C) unconformity is the major change in paleotemperature and paleobathymetry. The shallow marine to restricted marine subtropical fauna at the base of the Chattian is in strong contrast with the deeper marine and cooler upper Rupelian assemblages. This study suggests that the early Chattian transgression is genetically related to a widespread major warming pulse, known as the Late Oligocene Warming Event.