Interlaboratory comparison study of calibration standards for foraminiferal Mg/Ca thermometry

An interlaboratory study of Mg/Ca and Sr/Ca ratios in three commercially available carbonate reference materials (BAM RS3, CMSI 1767, and ECRM 752-1) was performed with the participation of 25 laboratories that determine foraminiferal Mg/Ca ratios worldwide. These reference materials containing Mg/C...

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Bibliographic Details
Authors: Greaves, Mervyn|||0000-0001-8014-8627, Caillon, Nicolas, Rebaubier, Helene, Bartoli, Gretta, Bohaty, Steven, Cacho, Isabel|||0000-0002-6512-0770, Clarke, Leon|||0000-0002-2278-4139, Cooper, Matthew J., Daunt, Caroline, Delaney, Margaret Lois, de Menocal, Peter|||0000-0002-7191-717X, Dutton, Andrea, Eggins, Stephen, Elderfield, Henry, Garbe-Schoenberg, Dieter, Goddard, Ethan, Green, Darryl R. H., Groeneveld, Jeroen, Hastings, David W., Hathorne, E., Kimoto, Katsunori, Klinkhammer, Gary, Labeyrie, Laurent D., Lea, David W., Marchitto, Thomas, Martínez Botí, Miguel Angel, Mortyn, P. Graham|||0000-0002-9473-4309, Ni, Yunyan|||0000-0003-1445-2676, Nuernberg, Dirk, Paradis, G., Pena, Leopoldo D.|||0000-0001-6414-6293, Quinn, Terrence M., Rosenthal, Yair, Russell, A., Sagawa, Takuya, Sosdian, Sindia M., Stott, Lowell|||0000-0002-2025-0731, Tachikawa, Kazuyo, Tappa, Eric J., Thunell, Robert C., Wilson, Paul A.
Format: article
Publication Date:2008
Country:España
Institution:Universitat Autònoma de Barcelona
Repository:Dipòsit Digital de Documents de la UAB
Language:English
OAI Identifier:oai:ddd.uab.cat:181774
Online Access:https://ddd.uab.cat/record/181774
https://dx.doi.org/urn:doi:10.1029/2008GC001974
Access Level:Open access
Keyword:Mg/Ca thermometry
Intercalibration
Reference materials
Paleoceanography
Carbonates
Description
Summary:An interlaboratory study of Mg/Ca and Sr/Ca ratios in three commercially available carbonate reference materials (BAM RS3, CMSI 1767, and ECRM 752-1) was performed with the participation of 25 laboratories that determine foraminiferal Mg/Ca ratios worldwide. These reference materials containing Mg/Ca in the range of foraminiferal calcite (0.8 mmol/mol to 6 mmol/mol) were circulated with a dissolution protocol for analysis. Participants were asked to make replicate dissolutions of the powdered samples and to analyze them using the instruments and calibration standards routinely used in their laboratories. Statistical analysis was performed in accordance with the International Standardization Organization standard 5725, which is based on the analysis of variance (ANOVA) technique. Repeatability (RSDr%), an indicator of intralaboratory precision, for Mg/Ca determinations in solutions after centrifuging increased with decreasing Mg/Ca, ranging from 0.78% at Mg/Ca = 5.56 mmol/mol to 1.15% at Mg/Ca = 0.79 mmol/mol. Reproducibility (RSDR%), an indicator of the interlaboratory method precision, for Mg/Ca determinations in centrifuged solutions was noticeably worse than repeatability, ranging from 4.5% at Mg/Ca = 5.56 mmol/mol to 8.7% at Mg/Ca = 0.79 mmol/mol. Results of this study show that interlaboratory variability is dominated by inconsistencies among instrument calibrations and highlight the need to improve interlaboratory compatibility. Additionally, the study confirmed the suitability of these solid standards as reference materials for foraminiferal Mg/Ca (and Sr/Ca) determinations, provided that appropriate procedures are adopted to minimize and to monitor possible contamination from silicate mineral phases.

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