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Radiocarbon in Porewater of Continental Shelf Sediments (Southeast Mediterranean)

Published online by Cambridge University Press:  18 July 2016

O Sivan ,
B Lazar ,
E Boaretto ,
Y Yechieli  and
B Herut
O Sivan*
Affiliation:
Institute of Earth Sciences, Hebrew University, Jerusalem 91904, Israel Geological Survey of Israel, Jerusalem 95501, Israel
B Lazar
Affiliation:
Institute of Earth Sciences, Hebrew University, Jerusalem 91904, Israel
E Boaretto
Affiliation:
Radiocarbon Dating Laboratory, ESER Dept. Weizmann Institute of Science, Rehovot 76100, Israel. Corresponding author. Email: elisabetta.boaretto@weizmann.ac.il
Y Yechieli
Affiliation:
Geological Survey of Israel, Jerusalem 95501, Israel
B Herut
Affiliation:
Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
*
Current address: Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA. Email: sivan@fas.harvard.edu.
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Abstract

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In this study, we aim to characterize the main processes controlling 14CDIC concentrations in porewater at the shallow shelf (water depth less than 120 m) off the Mediterranean coast of Israel. At these water depths, we expected to find evidence for seawater penetration toward the coast, since this area was flooded by seawater only some 18,000 yr ago (the end of the Last Glacial period).

Measurements of the chemical composition (14CDIC) and stable carbon isotopic composition (δ13CDIC) were performed in several sediment cores (40–250 cm long) at water depths between 6 and 115 m. At water depths of 60 m, represented by a 2.5-m-long sediment core, the porewater 14CDIC levels (85–87 pMC) were lower than the corresponding sediment values in each layer (92–95 pMC), mainly due to the oxidation of relatively old organic matter (about 70 pMC) with no evidence to advection. In contrast, sediment cores from water depths shallower than 50 m showed only slight anaerobic oxidation and high 14CDIC values of approximately 100 pMC, indicating possible downward advection. These geochemical observations support the perception that the penetration of seawater into the coastal aquifer occurs at the shallow water zone (<50 m), while further verification by deeper cores is required.

Type
Part II
Information
Radiocarbon , Volume 46 , Issue 2: Proceedings of the 18th International Radiocarbon Conference (Part 2 of 2), Conference Editors: Nancy Beavan Athfield, Rodger J Sparks , 2004 , pp. 633 - 642
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

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