Marine Isotope Stage (MIS) 11 represents a particularly intriguing interglacial period due to its orbital configuration, yet high-resolution terrestrial records from this interval remain scarce in the European Alps. Here, we present a detailed climate reconstruction spanning MIS 11 and the glacial inception into MIS 10 (∼415-360 kyr BP) from a composite record of four stalagmites (Swiss Alps), encompassing both conventional growth and subglacial deposition beneath warm-based ice during glacial periods — an emerging paleoclimate archive capable of preserving continuous records across the full interglacial-glacial transition. Precise U-series dating and stable isotope analyses of four overlapping stalagmites reveal marked temporal changes in climate variability: relative isotopic stability during the interglacial (415–380 kyr BP) followed by strongly increased variability during glacial inception and the subsequent glacial period (380–360 kyr BP). This transition is characterised by millennial-scale abrupt isotopic excursions that correlate with stadials and Heinrich-type events recorded in marine sediments from the Iberian Margin and North Atlantic. Remarkably, these speleothems provide the earliest radiometrically constrained evidence of millennial-scale climate oscillations during this glacial period in the Alps, having continued growing beneath warm-based ice. The onset of glacier expansion at 402 ± 4 kyr BP, predating global cooling in marine records, highlights the sensitivity of Alpine environments to early climate forcing driven by the combined effect of early cooling and sustained Atlantic moisture delivery. This demonstrates the complex interplay between orbital-scale and millennial-scale climate variability during the MIS 11-10 transition. • High-resolution composite speleothem record spanning MIS 11–10 (∼415–360 ka). • Subglacial speleothems document glacier advance at 402 ± 4 and 372 ± 2 ka. • Stadial-interstadial cycles recorded in the Alps during early MIS 10.
Honiat et al. (Mon,) studied this question.