The response of vegetation in SW Portugal to orbital and millennial climate variability during the MIS 21 interglacial complex

In recent years, the Portuguese Margin has emerged as the prime location for linking land and sea records and containing climatic signals that are of widespread geographical significance. A key aspect is that study sites are located near the continent, where the combined effects of the Tagus River and a narrow continental shelf lead to the rapid delivery of pollen to the deep-sea environment, but are also deep enough to monitor changes in Atlantic ocean circulation.

Pollen analysis will be undertaken on material from the iconic Site U1385. Stable isotopic analyses of planktic and benthic foraminifera in U1385 have already provided an unparalleled record of orbital and millennial climate variability over the last 1.45 million years (Hodell et al., 2023). The aim of the project is to reconstruct the sequence of vegetation changes during during Marine Isotope Stage (MIS) 21, 870-810 thousand years ago, an intriguing period containing four warm substages spaced ~10 kyr apart. No other marine isotopic stage contains such complexity. Of particular interest would be to explore whether the combined influence of orbital and millennial variability led to unique differences in the vegetation character of each substage. Results will be compared with foraminiferal isotopic and SST data from the same samples.

Hodell, D.A. et al., A 1.5-Million-Year Record of Orbital and Millennial Climate Variability in the North Atlantic. Clim. Past 19, 607-636 (2023).