Areal Distribution, Redeposition and Mixing of Tephra within Deep-Sea Sediments of the Eastern Mediterranean Sea

Abstract

Regional distributions of tephra deposits within Upper Quaternary pelagic sediments of the eastern Mediterranean and southern Aegean Seas have been determined from cores of deep-sea sediments. Reconstructions of the extent and thickness of individual ash layers required an evaluation of physical and biological redepositional processes, as well as possible mixing effects during sampling. Slumping or other mass-wasting processes on the sea-floor have significantly altered tephra distributions, as illustrated by regional variations in isopachs for the Z-2 Minoan and Y-5 Campanian Tbff ash layers; local variability can be equally significant as indicated by thickness variations of the Y-5 Campanian Tuff ash layer in a small area of the Mediterranean Ridge. Additional dispersal or mixing due to oceanic currents and biological activity, the latter primarily by benthic burrowing organisms, have also been important physical processes in both pre- and post-burial modification of ash layers.