Skip to main content Accessibility help
×
Home

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

  • Shari L Bush (a1), Guaciara M Santos (a1), Xiaomei Xu (a1), John R Southon (a1), Nivedita Thiagarajan (a2), Sophia K Hines (a2) and Jess F Adkins (a2)...

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.

Copyright

Corresponding author

2 Corresponding author. Email: gdossant@uci.edu.

References

Hide All
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.
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.
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.
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.
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.
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.
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.
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.
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.
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):8893.
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.
Type Description Title
EXCEL
Supplementary materials

Bush et al. supplementary material
Supplementary Table S1-S2

 Excel (52 KB)
52 KB

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed