Oxygen isotope composition of surface, thermocline and mid-depth western South Atlantic during Termination I and II

However, how different glacial terminations evolved in the (sub)tropics is still poorly documented. Here we use foraminifera oxygen (d18O) and carbon (d13C) stable isotopes to show that the North Atlantic heat piracy, following the AMOC resumption at the early Last Interglacial, affected the thermocline d18O levels of the subtropical western South Atlantic.

Because of the cooling imposed by this process, glacial d18O persisted in the thermocline for ~7 kyr after the onset of the Last Interglacial, dampening the effect of sea level rise usually imprinted on foraminifera d18O during terminations. Faunal composition and d13C also suggest the existence of a colder and thicker South Atlantic Central Water coeval with the AMOC recovery. This process apparently did not occur during the last deglaciation.