| Autor: |
Mechernich, S, Dunai, TJ, Binnie, SA, Goral, T, Heinze, S, Dewald, A, Schimmelpfennig, I, Keddadouche, K, Aumaître, G, Bourlès, D, Marrero, S, Wilcken, K, Simon, K, Fink, D, Phillips, FM, Caffee, MW, Gregory, LC, Phillips, R, Freeman, SPHT, Shanks, R, Akif Sarıkaya, M, Pavetich, S, Rugel, G, Merchel, S, Akçar, N, Yesilyurt, S, Ivy-Ochs, S, Vockenhuber, C |
| Jazyk: |
angličtina |
| Rok vydání: |
2019 |
| ISSN: |
0168-583X |
| Popis: |
Two natural mineral separates, labeled CoCal-N and CoFsp-N, have been prepared to serve as intercomparison material (ICM) for in situ-produced cosmogenic ³⁶Cl and natural chlorine (Clnat) analysis. The sample CoCal-N is derived from calcite crystals in a Namibian lag deposit, while the sample CoFsp-N is derived from a single crystal of alkali-feldspar from a Namibian pegmatite. The sample preparation took place at the University of Cologne and a rotating splitter was used to obtain homogeneous splits of both ICMs. Forty-five measurements of CoCal-N (between 1 and 16 per facility) and forty-four measurements of CoFsp-N (between 2 and 20 per facility) have been undertaken by ten target preparation laboratories measured by seven different AMS facilities. The internal laboratory scatter of the ³⁶Cl concentrations indicates no overdispersion for half of the laboratories and 3.9 to 7.3% (1σ) overdispersion for the others. We show that the CoCal-N and CoFsp-N splits are homogeneous regarding their ³⁶Cl and Clnat concentrations. The grand average (average calculated from the average of each laboratory) yields initial consensus ³⁶Cl concentrations of (3.74 ± 0.10) × 10⁶ at ³⁶Cl/g (CoCal-N) and (2.93 ± 0.07) × 10⁶ at ³⁶Cl/g (CoFsp-N) at 95% confidence intervals. The coefficient of variation is 5.1% and 4.2% for CoCal-N and CoFsp-N, respectively. The Clnat concentration corresponds to the lower and intermediate range of typical rock samples with (0.73 ± 0.18) µg/g in CoCal-N and (73.9 ± 6.8) µg/g in CoFsp-N. We discuss the most relevant points of the sample preparation and measurement and the chlorine concentration calculation to further approach inter-laboratory comparability. We propose to use continuous measurements of the ICMs to provide a valuable quality control for future determination of ³⁶Cl and Clnat concentrations. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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