Choosing the most conservative technique to extract unequivocally identifiable foraminiferal tests is crucial to avoid biases in sedimentary sequence dating and paleoenvironmental interpretations. However, for problematic samples containing heavily encrusted specimens, the concentration and isolation of microfossils might be challenging. In this work, we analyzed Early-Middle Pleistocene samples from the International Ocean Discovery Program (IODP) Site U1460, located on the southwestern Australian shelf platform, characterized by extensive early marine diagenesis. At this site, foraminiferal preservation varies between the glacial and interglacial phases. In particular, tests are highly encrusted in samples representing sea-level lowstands of glacials while exhibiting better preservation in samples corresponding to interglacials. As the application of previously established, very conservative preparation techniques (e.g., sieving technique, soaking in H₂O₂ solution and gentle sonication) did not produce satisfactory results, it was necessary to set up a new procedure for foraminifera isolation specifically for the cautious cleaning of cemented benthic and planktic foraminiferal tests. This new methodology combines the use of a freeze-dryer with repeated soakings in highly-diluted H₂O₂ solution to disaggregate the material. To evaluate the efficiency of our technique objectively, we considered the improvements obtained with our procedure on the worst-preserved samples of our record (corresponding to glacials) and the best-preserved (associated with interglacials). Despite being more time-consuming than other preparation techniques, this newly developed procedure produces excellent results in samples exhibiting a high level of encrustation for reliable quantitative studies and isotope analysis on foraminiferal assemblages. Our new methodology is highly conservative and thus preserving even delicate taxa.

选择最保守的技术来提取明确可识别的有孔虫测试对于避免沉积序列测年和古环境解释中的偏差至关重要。然而，对于含有严重结垢标本的有问题的样品，微化石的浓缩和分离可能具有挑战性。在这项工作中，我们分析了来自国际海洋发现计划 (IODP) 站点 U1460 的早中更新世样本，该站点位于澳大利亚西南部陆架台地，其特征是广泛的早期海洋成岩作用。在这个地点，有孔虫的保存在冰期和间冰期之间有所不同。特别是，在代表冰川海平面低位的样品中进行了高度结壳的测试，同时在与间冰期相对应的样品中表现出更好的保存。由于应用先前建立的、非常保守的制备技术（例如，筛分技术、在H ₂ O ₂溶液中浸泡和温和超声处理）没有产生令人满意的结果，因此有必要专门针对谨慎的有孔虫分离建立新的程序。胶结底栖和浮游有孔虫测试的清洁。这种新方法将冷冻干燥机的使用与在高度稀释的 H ₂ O ₂溶液中反复浸泡以分解材料相结合。为了客观地评估我们技术的效率，我们考虑了我们的程序对我们记录中保存最差的样本（对应于冰川）和保存最好的样本（与间冰期相关）所获得的改进。尽管比其他制备技术更耗时，但这种新开发的程序在表现出高水平结壳的样品中产生了出色的结果，可对有孔虫组合进行可靠的定量研究和同位素分析。我们的新方法是高度保守的，因此甚至保留了脆弱的分类单元。