Isotope Stratigraphy of the last glacial cycle (MIS 4 - MIS 1): Greenland stadials / interstadials; Dansgaard-Oeschger and Heinrich Events

Ice cores at the polar ice sheets (Greenland and Antarctica) have expanded the understanding of climate changes recorded by the marine stratigraphic scale of oxygen isotopes. The wide variety of data obtained, both from the analysis of ice and from the air trapped in bubbles, make the ice cores one of the palaeoclimatic records of highest quality. The variation in the isotope ratios of oxygen (partial derivative O-18), deuterium (partial derivative D) and other trace elements, together with the high chronological precision reached by annual layer counting and other dating methods, allow to establish a detailed chronological scale for MIS 4 to MIS 1, poorly represented in deep ocean cores. The Greenland ice-cores show a large climatic variability along this period, with very rapid warming events (Dansgaard - Oeschger events; Greenland interstadials) followed by slower cooling events (Greenland stadials), some of which particularly cold (Heinrich events). Comparison of these events with contemporary records in middle latitudes allows us to interpret the response of different sedimentary environments to such climatic variability. Two examples of these records have been selected: a speleothem from a karstic cave and a polygenic sedimentary sequence.