Turbidite flux, architecture and chemostratigraphy of the Herodotus Basin, Levantine Sea, SE Mediterranean

The Herodotus Basin is the deepest part of the SE Mediterranean and receives allochthonous sediments as turbidity currents and debris flows from around its margin. During the late Quaternary, characteristic supply has been from at least four sources. These are (1) dark coloured, calcium carbonate-poor fine-grained turbidites derived from the Nile Cone to the south and south-east, (2) lighter coloured, calcium carbonate-rich, slightly coarser-grained turbidites derived from the Libyan-Egyptian shelf to the south, (3) small, light brown foraminifer-rich, muddy-silty turbidites derived from the Cyprus-Eratosthenes seamount (Anatolian Rise) carbonate shelf to the east, and (4) small localized debris flow deposits derived from the Mediterranean Ridge to the north. During the late Quaternary (0–60 ka), and specifically the period of 0–27 ka, the basin has filled predominantly with allochthonous material derived from the Nile Cone, although one megaturbidite of basinwide extent was derived from the Libyan-Egyptian shelf. Turbidites have been correlated across the Herodotus Basin using the technique of chemostratigraphy. Matching the results of geochemical analysis may show whether or not the beds in different cores were deposited by the same mass-wasting event, for individual turbidites commonly have diagnostic and unique geochemical ‘fingerprints’ in terms of major, minor and trace element composition. Sediment budgets for the three main turbidite sources are calculated. The cumulative volume of the sedimentary input for the Nile Cone- derived turbidites over the last 27 ka is c. 500 km3, giving an average sedimentation rate of c. 45 cm ka−1, and a volume per unit time of 18 km3 ka−1. A megaturbidite, derived from the Libyan-Egyptian shelf, is of basinwide extent and has a volume of c. 400 km3.