Drilling the Marathousa palaeo‐lake in Greece (Peloponnese): inferring the environmental context of a Middle Pleistocene archaeological site

The Megalopolis Basin is located in the central Peloponnese (Greece), a region that is situated along one of the primary Pleistocene biogeographical corridors for intracontinental hominin migration. The basin comprises several hundred metres of Plio‐Pleistocene sediments alternating between clastics and lignites. Of these sediments, a 6 m thick succession deposited during the cold Marine Isotope Stage (MIS) 12 (~480–420 ka) was intensely studied after the discovery of evidence for hominin presence in these strata at the Marathousa 1 Lower Palaeolithic site. The local environmental conditions prior to and after this period, however, are still unknown. Here, we present the results of sedimentological analyses of two >100 m long drill cores (MAR18‐1A and MAR18‐2A) and two outcrops (MAR19‐2AP, Choremi‐6) in order to provide palaeoenvironmental constraints on the Megalopolis Basin between ~780 and 340 ka. Our age control is based on palaeomagnetic analysis conducted on the drill core MAR18‐1A and the Choremi‐6 outcrop, as well as correlations to formerly studied cores and outcrops. The geochemical and lithological proxies and their statistical processing reveal that the basin was characterized by a periodically changing environment influenced by a deltaic river during dry and/or cold intervals (clastic layer deposition) and lacustrine environments that were fringed by lush, limno‐telmatic vegetation during humid and/or warm periods (lignite seam formation). Our results provide high‐resolution insights into climatic changes in the immediate surrounding of the archaeological sites in the Megalopolis Basin during the Early to Middle Pleistocene, disclosing further investigation opportunities on palaeoclimate, palaeoenvironment and human activity in the region.