Preliminary results for the extraction and measurement of cosmogenic in situ C-14 from quartz

Naysmith, P., Cook, G.T., Phillips, W.M., Lifton, N.A. and Anderson, R. (2004) Preliminary results for the extraction and measurement of cosmogenic in situ C-14 from quartz. Radiocarbon, 46(1), pp. 201-206.

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Abstract

Radiocarbon is produced within minerals at the earth's surface (in situ production) by a number of spallation reactions. Its relatively short half-life of 5730 yr provides us with a unique cosmogenic nuclide tool for the measurement of rapid erosion rates ( gt 10(-3) cm yr(-1)) and events occurring over the past 25 kyr. At SUERC, we have designed and built a vacuum system to extract C-14 from quartz which is based on a system developed at the University of Arizona. This system uses resistance heating of samples to a temperature of approximately 1100 degreesC in the presence of lithium metaborate(LiBO2) to dissolve the quartz and liberate any carbon present. During extraction, the carbon is oxidized to CO2 in an O-2 atmosphere so that it may be collected cryogenically. The CO2 is Subsequently purified and converted to graphite for accelerator mass spectrometry (AMS) measurement. One of the biggest problems in measuring in situ C-14 is establishing a low and reproducible system blank and efficient extraction of the in situ C-14 Component. Here, we present initial data for C-14- free CO2, derived from geological carbonate and added to the vacuum system to determine the system blank. Shielded quartz samples (which should be C-14 free) and a surface quartz sample routinely analyzed at the University of Arizona were also analyzed at SUERC, and the data compared with values derived from the University of Arizona system.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cook, Professor Gordon and Naysmith, Mr Philip and Anderson, Mr Robert
Authors: Naysmith, P., Cook, G.T., Phillips, W.M., Lifton, N.A., and Anderson, R.
Subjects:Q Science > QE Geology
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Radiocarbon
Publisher:University of Arizona
ISSN:0033-8222
Copyright Holders:© 2004 by the Arizona Board of Regents on behalf of the University of Arizona
First Published:First published in Radiocarbon 46(1):201-206
Publisher Policy:Reproduced with the permission of the Publisher

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