Deep-water circulation in the northeast Atlantic during the mid- and Late Cretaceous

Abstract

Abstract The Cretaceous ocean was significantly different from its modern counterpart due to its ice-free condition. Deep waters were primarily sourced by evaporation at the ocean surface, although their circulation pattern and bottom-current dynamics have been largely unknown. Here we present a study of deeply buried contourite drifts in the southern proto–Bay of Biscay to unravel the circulation pattern of the mid- and Late Cretaceous deep waters across the northeast Atlantic. The generation of plastered drifts (120 Ma to 100–90 Ma) and a mounded drift (100–90 Ma to 65 Ma) suggests that a significant change in deep-water source regions from the Tethys to the high-latitude region occurred at ca. 100–90 Ma. These contourite drifts were buried after ca. 65 Ma when the Cretaceous ocean circulation transitioned to the Cenozoic style in the northeast Atlantic. Tectonic configurations of the Pyrenean and the Equatorial Atlantic gateways were moreover tied to significant changes in northeast Atlantic deep-water circulation at ca. 100–90 and ca. 65 Ma. Northeastern Spain and France might be potential sites for the detection of Late Cretaceous contourite outcrops. These outcrops could have fundamental implications for the sedimentary facies and sequence model of contourites as well as shed light on the paleoceanography and paleoclimate of Cretaceous Earth.