Insights on coccolith chemistry from a new ion probe method for analysis of individually picked coccoliths
Insights on coccolith chemistry from a new ion probe method for analysis of individually picked coccoliths
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通过新的离子探针方法分析单独采摘的颗石石，深入了解颗石石化学
DOI：
10.1029/2006gc001546
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发表时间：
2007
期刊：
影响因子：
3.7
通讯作者：
S. Zeren
中科院分区：
文献类型：
--
作者：
H. Stoll;N. Shimizu;A. Arevalos;N. Matell;Adam Banasiak;S. Zeren
钙质超微化石的元素化学可能为过去的海洋条件和球石类生理学提供有价值的信息，但来自非球石颗粒和变化的纳米化石组合的人工产物可能会偏离球石大小部分的地球化学记录。我们描述了第一种在显微操作器中使用钨针挑选单个球茎的方法。用二次离子质谱仪(SIMS)可以分析环氧固定球石的个体和种群。对于古新世沉积物，该技术区分了球石的高Sr/Ca比值(0.3~2.8 mm o l/m ol)和非生物成因方解石叶片的低m o l/m o l(0.1 m o l/m o l)。不同属的锶/钙比值具有很大的不均一性，表明原生地球化学差异并未被成岩隆起所均化，而晚古新世的厚重块状球石是生物成矿作用的主要特征。现代属的锶/钙比值平均高于古近纪属，但表现出类似的变异性水平。
The elemental chemistry of calcareous nannofossils may provide valuable information on past ocean conditions and coccolithophorid physiology, but artifacts from noncoccolith particles and from changing nannofossil assemblages may bias geochemical records from coccolith size fractions. We describe the first method for picking individual coccoliths using a tungsten needle in micromanipulator. Epoxy‐mounted individuals and populations of coccoliths can be analyzed by secondary ion mass spectrometry (SIMS). For Paleocene sediments the technique distinguishes the high Sr/Ca ratios of coccoliths (0.3 to 2.8 mmol/mol) from low ratios in abiogenic calcite blades (0.1 mmol/mol). The large heterogeneity of Sr/Ca ratios among different genera suggests that primary geochemical differences have not been homogenized by diagenetic overgrowth and the thick massive coccoliths of the late Paleocene are a primary feature of biomineralization. Sr/Ca ratios for modern genera are on average higher than those of Paleogene genera but exhibit a comparable level of variability.