Evolution of North Atlantic Deep Water inflow through the Yucatán Channel recorded by an obstacle-controlled contourite drift

Abstract

The deep Gulf of Mexico1 [see PDF for footnote] serves as a geological archive of variability in the Atlantic Meridional Overturning Circulation, reflecting changes in ventilation associated with the inflow of North Atlantic Deep Water. Recent studies outlined the development of the Loop Current through the identification of contourite drifts along the Yucatán Platform, yet the long-term evolution of its deep-water circulation remains poorly constrained. Here, we present an obstacle-controlled contourite drift formed by the deep water mass as it flows over the Yucatán Channel sill into the deep Gulf of Mexico. Lateral variations in drift geometry along the Pinar del Río Knoll demonstrate the influence of isolated bathymetric obstacles in modulating bottom current behavior and controlling drift morphology, hence providing insights into the Cenozoic evolution of the North Atlantic Deep Water inflow across the Yucatán Channel. Drift onset since the Eocene records the initiation of the Northern Component Water, or proto-North Atlantic Deep Water, and the reconfiguration of the Central American Seaway, while increased drift growth during the middle Miocene reflects the onset of the North Atlantic Deep Water and the progressive shoaling of the Central American Seaway.