MARINE ISOTOPE STAGE 4 CHANGES IN HYDROCLIMATE OF SOUTHERN PORTUGAL

Marine isotope stage (MIS) 4 spanned ~ 71 - 57 ka and was one of Europe's coldest segments of the last glacial period. Despite the increasingly harsh environment, evidence of early hominin migration throughout the Iberian Peninsula begins circa this interval. Speleothems can provide seasonal to decadal environmental data on vegetation and hydroclimate variability to identify former living conditions and provide high-resolution information on climatic shifts. In this study, we use stable carbon and oxygen isotopes and trace elemental abundances of a stalagmite collected in southern Portugal (Companheira Grande cave) that grew from ~ 69 – 64 ka, coeval with a relatively warm segment recorded in Greenland ice cores. Integrating these new data with regional records in Portugal, Spain, Italy, and France reveals a large latitudinal moisture gradient, with drier conditions in the north and wetter conditions to the south. In particular, the stalagmite growth ceased coincident with an extreme cold period recorded in Greenland. It did not restart after Heinrich event 6, which suggests that dry and cold conditions dominated this region of Europe. However, other regional stalagmite records continued growing during this exceptionally cold interval. The implications of these results will be discussed in the context of terrestrial and marine climatic boundary conditions during MIS 4.