Hostname: page-component-8448b6f56d-42gr6 Total loading time: 0 Render date: 2024-04-23T16:51:26.750Z Has data issue: false hasContentIssue false
  • English
  • Français

Radiocarbon Dating of Porewater – Correction for Diffusion and Diagenetic Processes

Published online by Cambridge University Press:  18 July 2016

Orit Sivan ,
Barak Herut ,
Yoseph Yechieli  and
Boaz Lazar
Orit Sivan*
Affiliation:
Institute of Earth Sciences, Hebrew University, Jerusalem 91904, Israel Geological Survey of Israel, Jerusalem 95501, Israel
Barak Herut
Affiliation:
Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
Yoseph Yechieli
Affiliation:
Geological Survey of Israel, Jerusalem 95501, Israel
Boaz Lazar
Affiliation:
Institute of Earth Sciences, Hebrew University, Jerusalem 91904, Israel The Moshe Shilo Minerva Center for Marine Biogeochemistry, Hebrew University, Jerusalem 91904, Israel
*
Corresponding author. Email: sivan@vms.huji.ac.il.
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Two simple algorithms are suggested here to correct for the effect of diffusion and diagenetic sulfate reduction on radiocarbon age determination of marine porewater. The correction algorithms were developed from mass balances of sulfate, dissolved inorganic carbon (DIC), and 14C of the DIC (14CDIC) in vertical concentrations profiles in porewater starting from the sediment water interface. The algorithms were tested on data collected during our recent study of sediment porewaters extracted from the deep Eastern Mediterranean. The real ages of these porewaters varied from present (top of the core) to approximately 30 ka BP (bottom of the core) covering most of the dynamic range of the 14C method (approximately 5 half lives). These ages were markedly older than the ages calculated from 14CDIC analyses by the regular age equation.

It is clearly demonstrated that in this case the correction of the apparent age for diffusion across the sediment/water interface is overwhelmingly larger than the correction for the effect of sulfate reduction. The correction for the effect of 14C diffusion alone results in a perfect match between the calculated apparent 14C ages and the real ages of porewater and therefore is the preferred algorithm for correcting apparent ages of porewater.

Type
II. Our ‘Wet’ Environment
Information
Radiocarbon , Volume 43 , Issue 2B: Proceedings of the 17th International Radiocarbon Conference (Part 2 of 3), Conference Editors: Israel Carmi, Elisabetta Boaretto , 2001 , pp. 765 - 771
Copyright
Copyright © 2001 by the Arizona Board of Regents on behalf of the University of Arizona 

References

Almagor, G, Schilman, B. 1995. Sedimentary structures and sediment transport across the continental slope of Israel from piston cores studies. Sedimentology 42:575–92.Google Scholar
Berner, RA. 1978. Early diagenesis. New Jersey: Princeton University Press.Google Scholar
Lerman, A. 1979. Geochemical processes. New York: John Wiley & Sons.Google Scholar
Mook, WG. 1980. Carbon 14 in hydrogeological studies. In: Frits, P, Fontes, JC, editors. Handbook of environmental isotope geochemistry I. p 49–74.Google Scholar
Neretnieks, I. 1980. Diffusion in the rock matrix: an important factor in radionuclide retardation? Journal of Geophys. Research 85(B8):4379–97.Google Scholar
Neretnieks, I. 1981. Age dating of groundwater in fissured rock: Influence of water volumes in micropores. Water Resour. Res. 17(2):421–2.Google Scholar
Sanford, WE. 1997. Correcting for diffusion in carbon-14 dating of ground water. Ground Water 35(2):357–61.Google Scholar
Sivan, O, Herut, B, Yechieli, Y, Boaretto, E, Heinemeier, J, Lazar, B. 2001. Inverse diffusive fluxes of 14C to 12C in deep sea sediment - impact on pore water dating. L&O. Forthcoming.Google Scholar
Stuiver, M, Polach, HA. 1977. Discussion reporting of 14C data. Radiocarbon 19(3):355–63.Google Scholar
Sudicky, EA, Frind, EO. 1981. Carbon 14 dating of groundwater in confined aquifers: Implications of aquitard diffusion. Water Resour. Res. 17(4): 1060–4.CrossRefGoogle Scholar
Walker, GR, Cook, PG. 1991. The importance of considering diffusion when using carbon-14 to estimate groundwater recharge to a confined aquifer. Journal of Hydrology 128:41–8.Google Scholar