Characterization of cores from the Black and Marmara Seas : implications for TOC source and preservation and potential for paleoenvironmental interpretation

Adetona, Kehinde B. (2005) Characterization of cores from the Black and Marmara Seas : implications for TOC source and preservation and potential for paleoenvironmental interpretation. Masters thesis, Memorial University of Newfoundland.

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    Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
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Abstract

Elemental (carbon, sulphur and biogenic opal) analysis was performed on the bulk sediments recovered from four core sites (MAR00-5, MAR00-6, and MAR00-8) in the Black Sea and core site MAR98-11 in the Marmara Sea. Isotopic (δ¹³C and δ ³⁴S) analysis was also performed on the bulk organic matter in the sediments. Linear extrapolations based on ¹⁴C dates in the three Black Sea cores indicate that while MAR00-6 is characterized by continuous and uniform sediment deposition, cores MAR00-5 and MAR00-8 lack a record of the last ∼5000 years. δ¹³C values from ∼-26‰ to ∼-23‰ for the TOC in the Black Sea cores indicate the mixing of isotopically light land-derived material with isotopically heavier autochthonous carbon derived from primary marine production. Interpretations from proxy data extracted from the cores suggest that relatively higher TOC contents in core MAR00-6 compared to the other Black Sea cores can be explained by better preservation of organic matter. This is attributed to the existence of a more stable stratified water-column well below wave base and/or greater salinity contrast between surface and bottom waters at this site before 5000 yr BP. -- Lithostratigraphic correlation to nearby core MAR98-12 with its ¹⁴C dates places sapropel deposition in core MAR98-11 between ∼9800 to ∼6600 yr BP, which coincides with the contemporaneous sapropel S1 in the Aegean Sea. δ¹³C values, the relatively high terrestrial organic-carbon component and other proxy data during this period point to a predominantly terrestrial source for the organic matter and reduced oxygen levels in the bottom waters. These data from core MAR98-11 broadly support the view of Aksu and coworkers that there has been a sustained brackish outflow from the Black Sea to the Mediterranean Sea via the intervening Marmara Sea since ∼11000-10500 yr BP.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/6526
Item ID: 6526
Additional Information: Bibliography: leaves 162-184.
Department(s): Science, Faculty of > Earth Sciences
Date: 2005
Date Type: Submission
Geographic Location: Black Sea; Turkey--Marmara, Sea of
Library of Congress Subject Heading: Marine sediments--Black Sea; Marine sediments--Turkey--Marmara, Sea of; Paleoceanography--Black Sea; Paleoceanography--Turkey--Marmara, Sea of

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