Problems and Possible Solutions Concerning Radiocarbon Dating of Surface Marine Sediments, Ross Sea, Antarctica

• Published in: Quaternary Research
• Main Authors: Andrews, John T., Domack, Eugene W., Cunningham, Wendy L., Leventer, Amy, Licht, Kathy J., Jull, A. J. Timothy, DeMaster, David J., Jennings, Anne E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1999
• Subjects: Ross Sea; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1006/qres.1999.2047; http://api.elsevier.com/content/article/PII:S0033589499920471?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:S0033589499920471?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400025795

Radiocarbon accelerator mass spectrometric (AMS) dates on the acid-insoluble fraction from 38 core tops from the western Ross Sea, Antarctica, are used to address these questions: (1) What are the apparent ages of sediments at or close to the present sediment/water interface? (2) Is there a statistically significant pattern to the spatial distribution of core top ages? and (3) Is there a “correction factor” that can be applied to these age determinations to obtain the best possible Holocene (downcore) chronologies? Ages of core top sediments range from 2000 to 21,000 14 C yr B.P. Some “old” core top dates are from piston cores and probably represent the loss of sediment during the coring process, but some core top samples >6000 14 C yr B.P. may represent little or no Holocene deposition. Four possible sources of variability in dates ≤6000 14 C yr B.P. ( n = 28) are associated with (1) different sample preparation methods, (2) different sediment recovery systems, (3) different geographic regions, and (4) within-sample lateral age variability. Statistical analysis on an a posteriori design indicates that geographic area is the major cause of variability; there is a difference in mean surface sediment age of nearly 2000 yr between sites in the western Ross Sea and sites east of Ross Bank in south-central Ross Sea. The systematic variability in surface age between areas may be attributed to: (a) variable sediment accumulation rates (SAR) (surface age is inversely related to SAR), (b) differences in the percentage of reworked ( dead ) carbon between each area, and/or (c) differences in the CO 2 exchange between the ocean and the atmosphere.