Holocene record of environmental changes and palaeoclimatic implications in Alykes Lagoon, Zakynthos Island, western Greece, Mediterranean Sea

Abstract

The present paper interprets the sedimentological, palaeontological and palynological data, retrieved from a 21 m depth core from the Alikes Lagoon of Zakynthos Island, in order to reconstruct the depositional environments and palaeoclimatic evolution of the area, as well as to estimate the rate of sedimentation from a time period between 8540 and 3400 BP. Sediment analyses include grain size analysis – moment measurements, definition of total organic carbon (TOC) and total nitrogen (TN). The foraminiferal analysis along the core was based on 44 sediment samples. The reconstructed depositional environments correspond to those of a coastal lagoon (restricted – shallow) and lagoon margins, with a series of intercalating events where marine characteristics dominate, and are related to climatic conditions, to the change in the communication of the coastal lagoon with the open sea and events such as storms or tsunami. From 80 pollen taxa which were determined, 25 are arboreal, 41 non-arboreal and 14 local. Four local pollen assemblage zones were classified. Different rates of sedimentation were observed along the core, including one of 39.14 mm/y, between 7250 and 7110 BP, which is one of the highest that has been observed in the coastal areas of western Greece. This event coincides in age with a general change in the coastal zone of Ionian Sea, correlated with a shift in the rate of relative sea level rise and local tectonic activity.