Implications of Late Quaternary Sea Level Changes on the Mediterranean and Black Sea Coasts, MEDBLACKS 2014, International Workshop, İstanbul, Turkey, 31 August - 06 September 2014, pp.49
Beachrocks of the Gökçeada and Bozcaada islands, which formed by cementation of slack beach sediments and shells with CaCO3, have a key role for understanding the features of paleocoastal environments with their characteristics such as composition, cement content, micromorphology and stable isotope composition. Sea-level changes and paleoclimatic-paleooceanographic changes can be interpreted correctly by considering the data, obtained from beachrock petrography and cement features together with choronostratigraphic data. In this study, the formation and paleacoastal features of beachrocks of 5 different parts of Gökçeada and Bozcaada islands are discussed. 15 samples were collected from these parts. Petrographic, analytic (XRD and SEM/EDX) and radiocarbon dating(14C) method was performed from the cement of the beachrocks to determine itsage and the conditions of formation.
BP 5830 – 5580 and 760-620 year radiocarbon ages were obtained from 15 samples, which were collected between +0,45m and -0,10 m heights from the sea level. Petrographic analyses show that the grains of beachrocks are metamorphic rock clastics, quartzite and limestone. Their cement is weak and grains are poorly rounded, which indicates short-distance transportation. Fossil shell fragments are also observed. These data show that the grains and bioclast of the beachrocks were deposited in a high energy environment. Micritic envelopes are common which show the early cementation on the grain surfaces. Radiometric data show that the beachrocks are belonging to 2 different periods which are ranging between BP 5830-3390 years and 2390-620 years similar to present day sea level. Between these 2 phases, sea level was probably lower than present day.
Key words:Beachrock, Cementation, Paleocoastal environment, Holocene, Gökçeada, Bozcaada
Acknowledgements: This study was supported by Research Foundation of ÇanakkaleOnsekiz Mart University (Project numbers:2010/162 and 2012/008) and is produced from Ph.D. thesis of the first author (M.A.).