An emerging palaeoceanographic 'missing link': Multidisciplinary study of rarely recovered parts of deep-sea Santonian-Campanian transition from Shatsky Rise

摘要

The Cretaceous deep-sea record of the Santonian-Campanian transition is commonly interrupted by an extensive unconformity (representing <10 Myr of hiatus). The resultant palaeoceanographic gap can now be partly bridged by a recent short core of pelagic ooze from Shatsky Rise (Integrated Ocean Drilling Program (IODP) Site U1348), with precise multidisciplinary age constraints developed herein. New oxygen isotope data from very well-preserved benthic foraminifera, together with accurately compiled comparable benthic data from previous Pacific deep-sea sections, exhibit a large (c. +1‰) early Campanian shift. We propose the Santonian-Campanian climatic transition was not gradual but was the first major cooling step after sustained mid-Cretaceous hothouse conditions.