Interglacial intensity in the North Atlantic over the last 800,000 years : investigating the complexity of the mid-Brunhes Event (MBE).

Abstract

The mid-Brunhes Event (MBE) represents a step-like increase, between Marine Isotope Stages (MIS) 13/11, in the intensity of interglacial warmth. A transect of palaeoclimatic records in the North Atlantic from 40°N to the Nordic Seas indicates strong differences in the expression of the MBE within this region. Between 40 and 56°N sea surface and air temperature records suggest that all interglacials of the past 800 000 years were characterized by similar levels of warmth, so there is no evidence for an MBE in these latitudes of the North Atlantic. North of 56°N there is increasing evidence for interglacials MIS 19–13 being cold relative to MIS 11–1. As most records of long-term interglacial diversity suggest the MBE is a global event the North Atlantic is clearly anomalous. Furthermore, the strong spatial difference in temperature conditions during interglacials MIS 19–13 in the North Atlantic means that the temperature gradient across this region would have been enhanced, in fact effectively doubled in magnitude, during this interval.