Abstract. The Last Interglacial serves as an excellent time interval for studying climate dynamics during past warm periods. Speleothems have been successfully used for reconstructing the paleoclimate of Last Interglacial continental Europe. However, all previously investigated speleothems are restricted to southern Europe or the Alpine region, leaving large parts of northwestern Europe undocumented. To better understand regional climate changes over the past, a larger spatial coverage of European Last Interglacial speleothems is essential. Here, we present new, high-resolution data from a stalagmite (Han-9) obtained from the Han-sur-Lesse cave in Belgium. The Han-9 formed between 125.3 and ~97 ka, with interruptions of growth occurring at 117.3–112.9 ka and 106.6–103.6 ka. The speleothem was investigated for its growth, morphology and stable isotope (δ13C and δ18O) content. Speleothem formation within the Last Interglacial started relatively late in Belgium, as this is the oldest sample of that time period found so far, dated at 125.3 ka. Other European continental archives suggest that Eemian optimum conditions were already present during that time, therefore it appears that the initiation of the Han-9 growth is caused by an increase in moisture availability, linked to wetter conditions around 125.3 ka. The δ13C and δ18O proxies indicate a period of relatively stable conditions after 125.3 ka, however at 120 ka the speleothem δ18O registered the first signs of regionally changing climate conditions, being a modification of ocean source δ18O linked to an increase in ice volume towards the MIS 5e-5d transition. The end of the Eemian is marked by drastic vegetation changes recorded in the speleothem δ13C at 117.5 ka, immediately followed by a stop in speleothem growth at 117.3 ka, suggesting that climate became significantly dryer. The Han-9 record covering the Early-Weichselian displays larger amplitudes in both the isotope proxies and the stalagmite morphology, evidencing increased variability compared to the Eemian. Greenland Stadials are recognized in the Han-9 and the chronology is consistent with other European (speleothem) records. Greenland Stadial 25 is reflected as a cold/dry period within the stable isotope proxies and the second interruption in speleothem growth occurs simultaneously with Greenland Stadial 24.
- paleoclimate, Last Interglacial, Eemian, northwestern Europe speleothem, stable isotopes, millennial variability, Greenland Stadials