The 161-ka Kos Plateau Tuff (KPT) eruption deposited widespread unwelded ignimbrites, but the Dikeos and Sympetro mountains on the SE of Kos Island blocked all but the most energetic pyroclastic flows. KPT remnants north of Sympetro mountain comprise reworked tuffite containing pumice and lithic clasts that petrologically and geochemically resemble those found in KPT unit E tephra, and reworked accretionary lapilli similar to those in KPT unit F. Tuffite is found only downslope from a 375-m-high pass between the Dikeos and Sympetro mountains, which was breached at the eruption climax by pyroclastic flows that then accelerated down the 10° north slope of Sympetro. The tuffite crops out in the palaeocliffs of a prominent terrace at an elevation of 75 m, interpreted as the transgressive ravinement surface of the first interglacial marine highstand after the KPT eruption during marine isotope stage (MIS) 5e. A similar ravinement surface cuts KPT deposits in central Kos at elevations of up to 135 m and implies post-MIS 5e uplift rates of 0.7–1.0 m ka−1, confirmed by the elevation of a previously reported raised beach beneath the KPT. A Holocene raised beach on the east coast of Kos contains pumice clasts from the Yali-4 eruption at 4–3 ka. Its elevation of 2 m above sea level is consistent with the elevation of the local MIS 5e terrace. Its present erosion results from the blocking of discharge from ephemeral streams by human infrastructure. Our study provides the first integrated chronologic and neotectonic interpretation of the prominent plateau and terrace surfaces on Kos Island.

The presence of glacial sediments across the Rauer Group indicates that the East Antarctic ice sheet formerly covered the entire archipelago and has since retreated at least 15 km from its maximum extent. The degree of weathering of these glacial sediments suggests that ice retreat from this maximum position occurred sometime during the latter half of the last glacial cycle. Following this phase of retreat, the ice sheet margin has not expanded more than ∼ 1 km seaward of its present position. This pattern of ice sheet change matches that recorded in Vestfold Hills, providing further evidence that the diminutive Marine Isotope Stage 2 ice sheet advance in the nearby Larsemann Hills may have been influenced by local factors rather than a regional ice-sheet response to climate and sea-level change.