Trace elements (TEs) in the calcite shells of foraminifera are widely used in paleoceanographic reconstructions. Nearly all TE analytical protocols include cleaning to remove contaminant phases. Understanding, how the TE composition is altered during physical and chemical cleaning is of utmost importance in ensuring the accuracy of paleoclimate reconstructions. Aggressive cleaning steps that include corrosive reagents are commonly used to clean shells with elevated Ba/Ca and Mn/Ca ratios, under the assumption that these elements are elevated due to diagenetic overprinting. We provide evidence that elevated intrashell Ba/Ca, Mn/Ca, and Zn/Ca ratios are lattice bound and a primary signal incorporated into inner calcite during calcification in the nonspinose species Neogloboquadrina dutertrei and Pulleniatina obliquiloculata. We first demonstrate, using laser ablation depth profiling analyses, that aggressive cleaning following the full cleaning protocol traditionally used to eliminate Mn and Ba contamination, preferentially removes inner (ontogenic) calcite and favors the low Ba/Ca, Mn/Ca, Zn/Ca, and Mg/Ca crust/cortex calcite. In a separate experiment, we demonstrate that mechanical fragmentation of bulk shells prepared for solution analysis also preferentially removes inner calcite and favors the low TE crust/cortex calcite. Preferential loss of the ontogenic calcite decreases Ba/Ca, Mn/Ca, and Zn/Ca ratios by 50%–90% in N. dutertrei and P. obliquiloculata shells. This biases foraminiferal TE results toward lower values and may yield data that is problematic for the interpretation of downcore records.

中文翻译：

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理化清洁过程中有孔虫中富含高方解石元素的方解石的优先损失

有孔虫方解石壳中的痕量元素（TEs）被广泛用于古海洋重建。几乎所有TE分析规程都包括清洁以去除污染物相。理解如何在物理和化学清洁过程中改变TE成分对于确保古气候重建的准确性至关重要。假定腐蚀性元素由于成岩性叠印而升高，通常会采用腐蚀性强的清洁步骤（包括腐蚀性试剂）来清洁具有较高的Ba / Ca和Mn / Ca比的壳体。我们提供的证据表明，壳层中的Ba / Ca，Mn / Ca和Zn / Ca比值受晶格约束，并且在非棘突物种Neogloboquadrina dutertrei和Pulleniatina obliquiloculata。我们首先使用激光烧蚀深度剖析分析证明，按照传统上用于消除Mn和Ba污染的完整清洁方案进行的积极清洁，优先去除内部（成因）方解石，并偏爱低Ba / Ca，Mn / Ca，Zn / Ca ，以及镁/钙结皮/皮质方解石。在一个单独的实验中，我们证明了为溶液分析准备的散装壳体的机械破碎还优先去除了内部方解石，并有利于低TE结壳/皮质方解石。个体发育方解石的优先损失减小的Ba /钙，锰/钙和Zn / Ca比值由50％-90％在N. dutertrei和P. obliquiloculata贝壳。这会使有孔虫的TE结果偏向较低的值，并可能产生对下层记录的解释有问题的数据。