High-Resolution Seismic Reflection Profiles for the Reconstruction of Postglacial Transgressive Shorelines: An example from Greece

Abstract

In 1982 we carried out a shallow-penetration, high-resolution seismic profiling study on the shelf of the southern Argolid, Peloponnesos, Greece, to identify and map the shores of the late Pleistocene and Holocene, and to establish their coastal environments. Portable equipment and a local boat were used. The lowest glacial shore occurs at −115 to −118 m, within the range of global values. The subsequent rise across the distinct old land surface left behind many shore features (scaps, beaches and beach ridges, channels and lagoons) now buried under a few meters of post-transgressive deposits. These features cluster at a small number of depths below present sea level, suggesting that the rise of the sea, usually too fast to leave an imprint, was episodically interrupted by brief stillstands or even temporary reversals of climatic or tectonic origin. The clusters can be roughly dated with reference to a global sea-level-rise curve; after 6000 yr B.P. sparse archaeological data establish a local curve. The seismic profiling technique, convenient and not costly, holds promise for the identification of postglacial shores elsewhere prior to sampling for dating. It has wide application for environmental reconstructions of vanished coastal zones as a basis for prehistoric resource assessments. These applications are illustrated with examples from this study.

Remote sensing for underwater archaeology: case stud-ies from Greece and Eastern Mediterranean

“…The clusters present synchronicity with relevant markers found along the coastline of Argolis Peninsula (Van Andel and Lianos, 1984) and coincide in age with stadials prevailed at this period (Rohling et al, 1998, Geraga et al, 2000. The above suggests that the transgression of the sea at the study area was not continuous during the Late Glacial-Holocene period but was interrupted for short time intervals.…”

“…In littoral environments with limited sediment supply the still-stands are imprinted as geomorphologic features, such as scarps and ridges. In the last decades the use of remote sensing techniques for the reconstruction of ancient coastal environments has become common practice because these techniques permit with high accuracy the identification and mapping of submerged palaeoshorelines located either on the seafloor or buried under unconsolidated postglacial sediments (van Andel and Shacleton, 1982, van Andel and Lianos, 1984, Papatheodorou and Ferentinos 1997, Wiedicke, et al, 1999.…”

Late Quaternary depositional history of the North Evvoikos Gulf, Aegean Sea, Greece

“…The lowest stands of the Mediterranean at about 120 m bsl (van Kapsimalis et al (2005) The values in parenthesis are estimated sill depths relative to present sea-level at the beginning of the Holocene, if they are thought to have differed significantly from today. Andel and Lianos, 1984) are of short duration as are the interglacial high stands and probably too short for much downcutting. By far the longest part of the Middle and Late Pleistocene, however, has been marked by sealevels between 50 m and 80 m bsl (Chappell and Shackleton, 1986;Shackleton, 1987;Lambeck and Chappell, 2001), close to the sill depths listed in Table 2.…”

Plio-Quaternary history of the Turkish coastal zone of the Enez-Evros Delta: NE Aegean Sea

“…Unit B is interpreted to have been deposited as a deltaic sequence progradation during a sea-level lowstand between the Würm glacial period (stage 2) and the following early phase of deglaciation (25,000-13,000 yrs BP) when the sea level dropped as much as 120 m below the present stand (VAN ANDEL & LIANOS, 1984;AKSU et al, 1987) and thus caused the exposure of the shelf areas once again. Similar progradational deltaic sequences occur along the coasts of western Anatolia as well as in the NW Aegean (Thermaikos Gulf, LYKOUSIS, 1991) where they are found below the present day deltas at 100-110 m water depths.…”