Ancient ocean sediments link changes in currents to cooling of Northern Hemisphere 3.6 million years ago

New research from an international group looking at ancient sediment cores in the North Atlantic has for the first time shown a strong correlation between sediment changes and a marked period of global cooling that occurred in the Northern Hemisphere some 3.6 million years ago. The changes in sediments imply profound changes in the circulation of deep water currents occurred at this time. This crucial piece of work, which showed sediments changed in multiple sites east of the mid-Atlantic ridge but not west of that important geographical feature, opens multiple doors to future research aimed at better understanding the link between deep water currents, Atlantic Ocean heat and salt distribution and ice-sheet expansion, and climatic change.