Holocene marine transgression in the Black Sea: New evidence from the northwestern Black Sea shelf

For two decades, the timing and rate of Holocene marine transgression and the level of the Black Sea prior to the transgression has been the focus of many geological, palaeoecological and archaeological studies. The potential importance of confirming or rejecting the catastrophic flood hypothesis by refining the chronology of the marine transgression and determining the water level of the early Holocene Black Sea (Neoeuxinian) lake is the aim of many ongoing Black Sea palaeoecological studies. In this report we review previous studies and present new data on the early Holocene marine transgression obtained from multidisciplinary studies of several cores from different parts of the Black Sea. Core 342 from the edge of the Dniester paleovalley on NW shelf is particularly important because it provides wood and leaf material from several peat and muddy peat beds, each up to similar to 10 cm thick, inter-layered in a coastal succession with mud, clay, and shell coquina. AMS ages for wood fragments and sedge leaves in the peat layers provide critical new data for calibrating and re-tuning of previously published shell and bulk detrital peat ages. Our multi-disciplinary study of geological material recovered from different shelf areas of the Black Sea refines the chronology of the marine transgression and clarifies conflicting interpretations of the water level and salinity of the Neoeuxinian lake prior to the initial Mediterranean inflow (IMI) and transgression of Mediterranean water in the Holocene, We find that: (1) The level of the Late Neoeuxinan lake prior to the early Holocene Mediterranean transgression stood around -40 m bsl but not -100 m or more as suggested by advocates of catastrophic/rapid/prominent flooding of the Black Sea by Mediterranean water. (2) At all times, the Neoeuxinan lake was brackish with salinity not less that 7 psu. (3) By 8.9 ka BP, the Black Sea shelf was already submerged by the Mediterranean transgression. An increase in salinity took place over 3600 years, with rate of the marine water incursion being estimated in the order of 0.05 cm-1.7 cm a(-1). (4) The combined data set of sedimentological characteristics and microfossil data establish that the Holocene marine transgression was of a gradual, progressive nature in the early Holocene. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.