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Prompt transgression and gradual salinisation of the Black Sea during the early Holocene constrained by amino acid racemization and radiocarbon dating

Journal Article


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Abstract


  • The restricted environment of the Black Sea is particularly sensitive to climatic and oceanographic

    fluctuations, owing to its connection with the Mediterranean Sea via the narrow Bosphorus Strait. The

    exact mechanism and timing of the most recent connection between these water bodies is controversial

    with debate on the post-glacial history of the Black Sea being dependent on radiocarbon dating for

    numerical ages. Here we present new 23 accelerator mass spectrometer (AMS) radiocarbon ages on peat

    and bivalve molluscs, supported by the first amino acid racemization (AAR) dating of bivalve molluscs

    (n ¼ 66) in the Black Sea. These data indicate infilling of the Black Sea during the early Holocene from an

    initial depth 107m below sea-level, and 72 m below that of the Bosphorus Sill. These data combined with

    a review of previous radiocarbon ages has enabled a unique perspective on the post-glacial Black Sea. A

    sea-level curve based on conventional and AMS radiocarbon ages on peat and AMS-based ages on

    Dreissena sp. shells indicate the water-level in the earlier lake phase continued, until the early Holocene,

    to be lower than the Bosphorus Sill after the Younger Dryas ended. However, the absence of AMS-dated

    mollusc ages from the shelves of this basin older than the Younger Dryas is suggestive of sub-aerial

    exposure of the shelves, and comparatively lower water-levels when the Younger Dryas began. Thus

    post-glacial outflow from the Black Sea occurred through a lowered or open Bosphorus seaway. Basinwide

    radiocarbon ages on peat indicate a prompt increase in water-level from that of the pre-existing

    and unconnected palaeo-lake during the earliest Holocene (9600e9200 cal a BP). Mass colonisation of

    the Black Sea by Mediterranean taxa did not occur until salinity had risen sufficiently, a process which

    took 1000 a or more from the initial transgressive event. This gradual change in salinity contrasts with

    the prompt transgression which would have taken w400 a to occur.

Publication Date


  • 2011

Citation


  • Nicholas, W. Anthony., Chivas, A. R., Murray-Wallace, C. V. & Fink, D. (2011). Prompt transgression and gradual salinisation of the Black Sea during the early Holocene constrained by amino acid racemization and radiocarbon dating. Quaternary Science Reviews, 30 (27-28), 3769-3790.

Scopus Eid


  • 2-s2.0-82355175063

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2140&context=scipapers&unstamped=1

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/1074

Number Of Pages


  • 21

Start Page


  • 3769

End Page


  • 3790

Volume


  • 30

Issue


  • 27-28

Abstract


  • The restricted environment of the Black Sea is particularly sensitive to climatic and oceanographic

    fluctuations, owing to its connection with the Mediterranean Sea via the narrow Bosphorus Strait. The

    exact mechanism and timing of the most recent connection between these water bodies is controversial

    with debate on the post-glacial history of the Black Sea being dependent on radiocarbon dating for

    numerical ages. Here we present new 23 accelerator mass spectrometer (AMS) radiocarbon ages on peat

    and bivalve molluscs, supported by the first amino acid racemization (AAR) dating of bivalve molluscs

    (n ¼ 66) in the Black Sea. These data indicate infilling of the Black Sea during the early Holocene from an

    initial depth 107m below sea-level, and 72 m below that of the Bosphorus Sill. These data combined with

    a review of previous radiocarbon ages has enabled a unique perspective on the post-glacial Black Sea. A

    sea-level curve based on conventional and AMS radiocarbon ages on peat and AMS-based ages on

    Dreissena sp. shells indicate the water-level in the earlier lake phase continued, until the early Holocene,

    to be lower than the Bosphorus Sill after the Younger Dryas ended. However, the absence of AMS-dated

    mollusc ages from the shelves of this basin older than the Younger Dryas is suggestive of sub-aerial

    exposure of the shelves, and comparatively lower water-levels when the Younger Dryas began. Thus

    post-glacial outflow from the Black Sea occurred through a lowered or open Bosphorus seaway. Basinwide

    radiocarbon ages on peat indicate a prompt increase in water-level from that of the pre-existing

    and unconnected palaeo-lake during the earliest Holocene (9600e9200 cal a BP). Mass colonisation of

    the Black Sea by Mediterranean taxa did not occur until salinity had risen sufficiently, a process which

    took 1000 a or more from the initial transgressive event. This gradual change in salinity contrasts with

    the prompt transgression which would have taken w400 a to occur.

Publication Date


  • 2011

Citation


  • Nicholas, W. Anthony., Chivas, A. R., Murray-Wallace, C. V. & Fink, D. (2011). Prompt transgression and gradual salinisation of the Black Sea during the early Holocene constrained by amino acid racemization and radiocarbon dating. Quaternary Science Reviews, 30 (27-28), 3769-3790.

Scopus Eid


  • 2-s2.0-82355175063

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2140&context=scipapers&unstamped=1

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/1074

Number Of Pages


  • 21

Start Page


  • 3769

End Page


  • 3790

Volume


  • 30

Issue


  • 27-28