Climate instability in the European Alps across MIS 10 and 11

The MIS 10 glacial period was characterized by vast ice sheets and cold climates, but reconstructing its history is challenging due to erosion and burial under modern glaciers. In contrast, the preceding MIS 11 interglacial lacks clear markers for some substages, despite its well-defined peak. As MIS 11 is often considered a partial analogue to the Holocene, understanding its transition into MIS 10 could provide valuable insights into future climate scenarios.

Research on MIS 10 and MIS 11a/b is limited by their temporal remoteness and the scarcity of well-preserved records. While studies tend to focus on more recent ice ages, terrestrial data such as lake sediments and loess sequences are rare. Although ice cores offer detailed records, they primarily cover younger periods. Subglacial speleothems, however, have emerged as a valuable alternative, providing high-resolution, U/Th dated archives even for older glacial climates.

This study examines subglacial speleothems from the Schratten karst in Switzerland’s Melchsee-Frutt region. Stable-isotope data reveal distinct patterns: stable signals during warm interglacial periods and unstable signals during colder phases, linked to moisture sources from the North Atlantic. These findings provide the first high-resolution reconstruction of MIS 10 and MIS 11a/b climate events for this region.

The study highlights the underexplored potential of subglacial speleothems as critical tools for studying glacial-interglacial transitions and improving our understanding of ancient climates, with implications for future scenarios.