Redating the formation of Lake Bafa, western Turkey: Integrative geoarchaeological methods and new environmental and dating evidence

The ancient Gulf of Latmos is an iconic example of a dynamic landscape and humankind's historical relationship with it. Using extensive new primary data and original models for calibrating radiocarbon dates in transitional lagoon environments, we demonstrate that Lake Bafa (or Bafa Gölü, in Turkish) formed at a much earlier date than previously thought. In questioning the logical process by which previous dates were achieved, we re‐examine the relationship between sedimentological data, archaeology and written history. We reassert the need to establish independently dated environmental data sets as the foundation of regional studies as distinct from archaeological and historical interpretive processes. We conclude that Lake Bafa slowly transitioned to become an isolated lagoon sometime between the end of the second millennium B.C. and end of the first millennium B.C.; becoming a fully closed brackish lake during the second millennium A.D. This marks a major shift in our understanding of the nature of human occupation and activity here during the last four millennia but also in the way we date ancient lagoons and integrate historical and environmental data in general

A mid-late Holocene sapropelic sediment unit from the southern Marmara sea shelf and its palaeoceanographic significance

A sapropelic layer, having an age of ca 4750 and 3500 (14)C y BP, was discovered at 0.90-2.35 m below the sea floor (mbsf) in gravity cores from the southern shelf of the Marmara Sea. It is a 15-50 cm thick, phosphorescent green to grey, plastic, clayey hemipelagic mud horizon, containing 1.5-2.9% organic carbon (C(org)). The increase in C(org) and biogenic carbonate, together with a rich planktonic foraminiferal fauna, indicate increased organic productivity and warm surface waters during the deposition of the sapropelic layer. The down-core profiles of Mn, Fe, Cu, Zn, Pb, Cr, Ni and Co suggest that the sapropelic layer was deposited through an essentially oxic water column. The benthonic foraminiferal fauna indicates reduced oxygen levels in bottomwaters. The sapropelic unit was deposited during a high stand of global sea level. Its deposition was initiated by a large input of terrestrial organic matter and nutrient-rich fresh waters under a relatively warm and wet climate. The fresh water supply caused a strong water stratification, which, in turn, together with high organic matter input, resulted in reduced oxygen levels in the bottomwaters. (C) 1999 Elsevier Science Ltd. All rights reserved

The Sea of Marmara during Marine Isotope Stages 5 and 6

Multi-proxy analyses and lithology of two cores, MRS-CS18 and MRS-CS27, from the İmralı Basin of the Sea of Marmara (SoM) provide novel information on environmental conditions, relative sea level, and sill depths of the straits of Bosporus and Dardanelles during the Marine Isotope Stages (MIS) 5 and 6. The fossil and multi-proxy geochemical records show that lacustrine conditions prevailed in the SoM during most of MIS 6, from 171 to 134 ka BP, and that the transition to marine conditions during Termination II took place at ∼134.06 ± 1.10 ka BP. MIS 5 interstadials a, c, and e witnessed the formation of three sapropels (MSAP-2, MSAP-3 and MSAP-4) under suboxic to anoxic marine conditions, whereas during stadials MIS 5b (∼94–86) and MIS 5d (∼112–105 ka BP), lacustrine and marine conditions with deposition of sediments having relatively low TOC contents (<2%) prevailed, respectively. Consideration of the global sea level, together with the timing of the marine reconnection of the SoM during Termination II and persistence of the marine conditions during MIS 5, except for MIS 5b and later part of MIS 5a, suggests that the Dardanelles sill depth was at ∼ -75 ± 5 m during the reconnection at Termination II and at −55 ± 5 m during most of MIS 5. On similar considerations of the Black Sea marine reconnections and disruptions during the MIS 5, a sill depth of −35 to −40 m (similar to the present day depth) is indicated for the Bosporus Strait. The SoM geochemical proxy records correlate well with the regional terrestrial and marine records and the NGRIP oxygen isotope record with its Stadial and Interstadial phases, showing the common effect of the North Atlantic climatic events triggered by the perturbations in the Atlantic Meridional Overturning Circulation. However, the amplitude of the oscillations recorded in the SoM during MIS 6 (Penultimate Glacial Period) is relatively small compared to the MIS 4 to MIS 2 (Last Glacial Period)