Sedimentology and micromorphology of the Lower Palaeolithiclakeshore site Marathousa 1, Megalopolis basin, Greece

The present study describes the sedimentology and formation processes of the archaeological siteMarathousa 1, part of a Pleistocene lignite-bearing succession at the Megalopolis basin (SouthernGreece). The sedimentary sequence of the site comprises about 4e5 m lacustrine andfluviolacustrineclastic deposits found between Lignite Seam II and III. The lower part of this sequence is characterized byrelatively high rate subaqueous sedimentation of bedded sands and silts with local evidence of slumpingand liquefaction attributed to a seismic event. This part of the sequence containsfluctuating butgenerally low organic and carbonate content probably associated with cold and arid conditions of aglacial period. The upper part of the sequence follows a major hiatus attributed to exposure and erosion.A series of erosional bounded depositional units are observed in this sequence suggesting importantwater-levelfluctuations. The subaqueous emplacement of the deposits is attributed to subaerialflood-generated, organic- and carbonate-rich dilute mudflows and hyperconcentratedflows. Organic-richsedimentation culminates with the formation of the overlying lignite seam. This change is interpretedas a gradual return to warmer and humid conditions of an interglacial period.The fossiliferous and cultural levels at Marathousa 1 are associated with the major erosional andexposed surface found in the upper part of the sequence. This surface was part of an extensive mudflatsurrounding the lake shore at that time. The overlying mudflows have locally redistributed and buriedthe archaeological remains, thus preserving this very important butchering site.