Over the past 230,000 years, the growth and retreat of the Icelandic ice sheet have led to major changes in the seawater chemistry of the North Atlantic, caused by the interaction between volcanism and ice in Iceland. Scientists at the Institute of Environmental Physics at Heidelberg University have demonstrated this using sediment cores from the northeastern Atlantic – the Rockall Plateau. The researchers analyzed the isotopic composition of the rare-earth element neodymium in these drill cores. According to their findings, the isotopic signal fluctuated significantly over the course of glacial and interglacial periods, following the “rhythm” of the ice ages, as shown by the studies led by Prof. Dr. Norbert Frank.

At the end of the last ice age, about 18,000 years ago, the Atlantic overturning circulation weakened significantly for several thousand years. Researchers from Bremen and Brazil have now analyzed a high-temporal-resolution sediment core that allows for a more precise reconstruction of this so-called Heinrich event at a temporal resolution of centuries. The study, published in Nature Communications, shows that during this prolonged period of weakness, short-term intensifications of the circulation lasting several centuries occurred.