Beachrock as evidence of sea-level lowstand during the classical period, Parion antique city, Marmara Sea, Turkey

Results obtained from beachrock lying on the north coast of the antique city of Parion in Canakkale province, NW Turkey, are presented based on field data, petrographic analyses, cement fabrics, and radiocarbon dating. Extending to 20m offshore at a depth of -2m, the studied 50-cm thick beachrock is poorly sorted lithic sandstone. Both exposed and submerged parts are characterized by sequentially precipitated marine phreatic and vadose cements composed of micrite encrustations with micro-organism borings, pseudopeloidal aggregates of high-Mg calcites with scalenohedral habits and meniscus bridges. Radiocarbon ages point to a deposition during the classical period when the sea level was below (between -1 and -1.5m) that of the present. The beachrock witnesses a granule- and pebble-dominated wide beach prior to cementation, suggesting that Parion's fortification walls were behind the coastline during this lowstand and raises questions concerning the existence of a harbor north of the city.