Sub-Permil Interlaboratory Consistency for Solution-Based Boron Isotope Analyses on Marine Carbonates
Sub-Permil Interlaboratory Consistency for Solution-Based Boron Isotope Analyses on Marine Carbonates
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DOI：
10.1111/ggr.12364
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发表时间：
2020-11-11
影响因子：
3.8
通讯作者：
You, Chen-Feng
中科院分区：
文献类型：
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作者：
Gutjahr, Marcus;Bordier, Louise;You, Chen-Feng
在地球历史上，海洋碳酸盐中的硼同位素越来越多地被用来重建海水pH和大气PCO(2)。虽然各个实验室的同位素比率测量往往质量很高，但重要的是可以平等地比较不同实验室产生的记录。在这项硼同位素对比项目(BIIP)中，我们研究了两个海相碳酸盐的硼同位素组成(通常以增量B-11表示)：日本地质调查局碳酸盐标准物质JCP-1(珊瑚Porites)和JCT-1(巨蚌Tridacna Gigas)。我们的研究有三个重点：(A)评估旨在从碳酸盐中去除有机物质的氧化前处理对所产生的三角洲B-11的影响程度；(B)确定所选的分析方法可能在多大程度上影响所得到的三角洲B-11；以及(C)为JCP-1和JCT-1提供严格约束的共识三角洲B-11值。未氧化的JCP-1的稳健平均值和相关稳健标准偏差(S*)为24.36+/-0.45ppm(2s*)，而相同氧化材料的稳健平均值和相关稳健标准偏差(2s*)为24.25+/-0.22ppm(2s*)。对于未氧化的JCT-1，其组成分别为16.39+/-0.60 ppm(2s*；未氧化)和16.24+/-0.38 ppm(2s*；氧化)。如果碳酸盐粉末在提纯和测量之前被氧化清洗，实验室之间的一致性通常会更好。
Boron isotopes in marine carbonates are increasingly used to reconstruct seawater pH and atmospheric pCO(2) through Earth's history. While isotope ratio measurements from individual laboratories are often of high quality, it is important that records generated in different laboratories can equally be compared. Within this Boron Isotope Intercomparison Project (BIIP), we characterised the boron isotopic composition (commonly expressed in delta B-11) of two marine carbonates: Geological Survey of Japan carbonate reference materials JCp-1 (coral Porites) and JCt-1 (giant clam Tridacna gigas). Our study has three foci: (a) to assess the extent to which oxidative pre-treatment, aimed at removing organic material from carbonate, can influence the resulting delta B-11; (b) to determine to what degree the chosen analytical approach may affect the resultant delta B-11; and (c) to provide well-constrained consensus delta B-11 values for JCp-1 and JCt-1. The resultant robust mean and associated robust standard deviation (s*) for un-oxidised JCp-1 is 24.36 +/- 0.45 parts per thousand (2s*), compared with 24.25 +/- 0.22 parts per thousand (2s*) for the same oxidised material. For un-oxidised JCt-1, respective compositions are 16.39 +/- 0.60 parts per thousand (2s*; un-oxidised) and 16.24 +/- 0.38 parts per thousand (2s*; oxidised). The consistency between laboratories is generally better if carbonate powders were oxidatively cleaned prior to purification and measurement.