Comparison of δ 18 O analyses on individual planktic foraminifer ( Orbulina universa ) shells by SIMS and gas-source mass spectrometry
Comparison of δ 18 O analyses on individual planktic foraminifer ( Orbulina universa ) shells by SIMS and gas-source mass spectrometry
复制标题
通过 SIMS 和气源质谱法对单个浮游有孔虫 (Orbulina universa) 壳进行 δ 18 O 分析的比较
DOI：
10.1016/j.chemgeo.2018.02.028
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Valley, John W.
中科院分区：
文献类型：
--
作者：
Wycech, Jody B.;Kelly, Daniel Clay;Kozdon, Reinhard;Orland, Ian J.;Spero, Howard J.;Valley, John W.
通过二次离子质谱 (SIMS) 和需要对方解石样品进行酸消化的传统气源质谱 (GSMS) 进行原位测量，测量了浮游有孔虫 Orbulina universa 各个壳的最终室碎片的氧同位素 (δ18O) 组成。对取自沉积物核心（全新世）顶部的化石贝壳的最终室碎片以及实验室培养的贝壳进行配对的 SIMS-GSMS 分析。对经过各种清洁方案处理的最终腔室碎片进行多次 SIMS-GSMS 分析。这一系列配对分析得出平均 SIMS-GSMS δ18O 偏移 (Δ18OSIMS-GSMS) 为 −0.9±0.1‰ (±2 SE)。 10μm SIMS 点分析的材料体积比 GMS 分析的材料体积小约 105 倍；因此，这些 Δ18OSIMS-GSMS 值在多大程度上代表分析物与仪器因素的实际差异仍不清楚。造成 SIMS-GSMS δ18O 差异的可能因素包括 SIMS 的样品与标准不匹配、SIMS 和 GSMS 标准化的差异以及样品中的非方解石污染物。尽管两个数据集始终存在偏移，但 SIMS 值再现了由壳碎片 GMS 值描绘的壳间 δ18O 变异性。事实证明，这种强正协方差有助于使两个数据集保持一致（即 Δ18OSIMS-GSMS=0），并证实基于 SIMS 的有孔虫 δ18O 值记录了海水钙化温度和/或 δ18O 的变化。具有不同微晶结构、化学成分和/或保存历史的有孔虫类群的壳是否记录相似的 Δ18OSIMS-GSMS 值是正在进行的测试的主题。
The oxygen isotope (δ18O) compositions of final chamber fragments of individual shells of the planktic foraminiferOrbulina universawere measuredin situvia secondary ion mass spectrometry (SIMS) and by traditional gas-source mass spectrometry (GSMS) entailing acid digestion of sampled calcite. The paired SIMS-GSMS analyses were performed on final chamber fragments of fossil shells taken from the top of a sediment core (Holocene) as well as shells grown in laboratory culture. Multiple iterations of SIMS-GSMS analyses were conducted on final chamber fragments treated with a variety of cleaning protocols. The series of paired analyses yielded an average SIMS-GSMS δ18O offset (Δ18OSIMS-GSMS) of −0.9 ± 0.1‰ (±2 SE). The volume of material analyzed in 10-μm SIMS spots is ~105times smaller than that analyzed by GSMS; hence, the extent to which these Δ18OSIMS-GSMSvalues represent real differences in analyte vs. instrumental factors remains unclear. Possible contributing factors to the SIMS-GSMS δ18O difference include sample-standard mismatch by SIMS, differences in standardization of SIMS and GSMS, and non-calcite contaminants in samples. Although the two datasets are consistently offset, SIMS values reproduce inter-shell δ18O variability delineated by shell fragment GSMS values. This strong positive covariance proved useful for bringing the two datasets into agreement (i.e. Δ18OSIMS-GSMS= 0), and confirms that SIMS-based foraminifer δ18O values record changes in calcification temperature and/or δ18O of seawater. Whether shells of foraminifer taxa with differing microcrystalline structures, chemical composition, and/or preservation histories register a similar Δ18OSIMS-GSMSvalue is a subject of ongoing testing.