Hostname: page-component-76fb5796d-45l2p Total loading time: 0 Render date: 2024-04-26T13:47:15.067Z Has data issue: false hasContentIssue false
  • English
  • Français

Simple, Rapid, and Cost Effective: A Screening Method for 14C Analysis of Small Carbonate Samples

Published online by Cambridge University Press:  09 February 2016

Shari L Bush ,
Guaciara M Santos ,
Xiaomei Xu ,
John R Southon ,
Nivedita Thiagarajan ,
Sophia K Hines  and
Jess F Adkins
Shari L Bush
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697–3100, USA
Guaciara M Santos*
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697–3100, USA
Xiaomei Xu
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697–3100, USA
John R Southon
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697–3100, USA
Nivedita Thiagarajan
Affiliation:
California Institute of Technology, Pasadena, California 91125, USA
Sophia K Hines
Affiliation:
California Institute of Technology, Pasadena, California 91125, USA
Jess F Adkins
Affiliation:
California Institute of Technology, Pasadena, California 91125, USA
*
2Corresponding author. Email: gdossant@uci.edu.
Get access Rights & Permissions [Opens in a new window]

Abstract

We have developed a simple, rapid method to screen carbonates for survey applications, which provides radiocarbon dates with decreased precision at lower cost. The method is based on previous work by Longworth et al. (2011) and involves mixing pulverized CaCO3 with Fe powder, followed by pressing into aluminum target holders for direct 14C accelerator mass spectrometry (AMS) measurements. An optimum beam current averaging ∼10% of those produced by >0.7 mg C graphite targets was obtained for carbonate samples of 0.3–0.5 mg (0.04–0.06 mg C). The precision of the method was evaluated by measuring triplicates of 14C reference materials, as well as by comparing results from this rapid method with results from high-precision AMS measurements on graphite (typically 0.2–0.3%). Measurement reproducibility was ∼1.8% (1σ) for samples <10 ka BP, and it increased drastically for older samples. However, t tests on paired samples resulted in p values greater than 0.05, indicating a good correlation between this survey method and the conventional one. An average blank (calcite) of 0.0075 Fm (∼39 ka BP) was achieved. The simplicity of the technique allowed us to process and measure 72 deep-sea coral samples in less than 25 hr.

Type
Articles
Information
Radiocarbon , Volume 55 , Issue 2: Proceedings of the 21st International Radiocarbon Conference (Part 1 of 2) , 2013 , pp. 631 - 640
Copyright
Copyright © 2013 by the Arizona Board of Regents on behalf of the University of Arizona 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Beverly, RK, Beaumont, W, Tauz, D, Ormsby, KM, von Reden, KF, Santos, GM, Southon, JR. 2010. The Keck Carbon Cycle AMS Laboratory, University of California Irvine: status report. Radiocarbon 52(2):301–9.Google Scholar
Burke, A, Robinson, LF, McNichol, AP, Jenkins, WJ, Scanlon, KM, Gerlach, DS. 2010. Reconnaissance dating: a new radiocarbon method applied to assessing the temporal distribution of Southern Ocean deep-sea corals. Deep-Sea Research I 57(11): 1510–20.Google Scholar
Longworth, BE, Robinson, LF, Roberts, ML, Beaupre, SR, Burke, A, Jenkins, WJ. 2013. Carbonate as sputter target material for rapid 14C AMS. Nuclear Instruments and Methods in Physics Research B 294:328–34.CrossRefGoogle Scholar
McIntyre, CP, Roberts, ML, Burton, JR, McNichol, AP, Burke, A, Robinson, LF, von Reden, KF, Jenkins, WJ. 2011. Rapid radiocarbon (14C) analysis of coral and carbonate samples using a continuous-flow accelerator mass spectrometry (CFAMS) system. Paleoceanography 26: PA4212, doi: 10.1029/2011PA002174.Google Scholar
Robinson, LF, Adkins, JF, Scheirer, DS, Fernandez, DP, Gagnon, A, Waller, RG. 2007. Deep-sea scleractinian coral age and depth distributions in the northwest Atlantic for the last 225,000 years. Bulletin of Marine Science 81(3):371–91.Google Scholar
Santos, GM, Mazon, M, Southon, JR, Rifai, S, Moore, R. 2007a. Evaluation of iron and cobalt powders as catalysts for 14C-AMS target preparation. Nuclear Instruments and Methods in Physics Research B 259(1): 308–15.Google Scholar
Santos, GM, Moore, RB, Southon, JR, Griffin, S, Hinger, E, Zhang, D. 2007b. AMS 14C sample preparation at the KCCAMS/UCI Facility: status report and performance of small samples. Radiocarbon 49(2):255–69.CrossRefGoogle Scholar
Santos, GM, Southon, JR, Griffin, S, Beaupre, SR, Druffel, ERM. 2007c. Ultra small-mass 14C-AMS sample preparation and analyses at KCCAMS Facility. Nuclear Instruments and Methods in Physics Research B 259(1):293–302.CrossRefGoogle Scholar
Santos, GM, Southon, JR, Drenzek, NJ, Ziolkowski, LA, Druffel, E, Xu, XM, Zhang, D, Trumbore, S, Eglinton, TI, Hughen, KA. 2010. Blank assessment for ultra-small radiocarbon samples: chemical extraction and separation versus AMS. Radiocarbon 52(3): 1322–35.CrossRefGoogle Scholar
Southon, JR, Santos, GM. 2007. Life with MC-SNICS. Part II: further ion source development at the Keck Carbon Cycle AMS facility. Nuclear Instruments and Methods in Physics Research B 259(1):88–93.CrossRefGoogle Scholar
Thiagarajan, N, Gerlach, D, Roberts, ML, Burke, A, McNichol, A, Jenkins, WJ, Subhas, AV, Thresher, RE, Adkins, JF. 2013. Movement of deep-sea coral populations on climatic timescales. Paleoceanography 28(2):227–36.CrossRefGoogle Scholar
Supplementary material: File

Bush et al. supplementary material

Supplementary Table S1-S2

Download Bush et al. supplementary material(File)
File 52.2 KB