Development of the freeze–thaw processing technique for disaggregation of indurated mudrocks and enhanced recovery of calcareous microfossils
Development of the freeze–thaw processing technique for disaggregation of indurated mudrocks and enhanced recovery of calcareous microfossils
复制标题
硬质泥岩解聚及钙质微化石强化回收冻融处理技术开发
DOI：
10.1144/jmpaleo2013-020
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
A. Coe
中科院分区：
文献类型：
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作者：
Alice E. Kennedy;A. Coe
从硬结泥岩中提取微体化石被广泛认为是具有挑战性的，特别是对于有孔虫。在这里，我们报告的发展冻融提取方法，通过增加快速加热，洗涤剂和超声阶段。我们使用来自英国约克郡的Toarcian（早侏罗世）的硬化泥岩样品来评估冻融方法的有效性并开发冻融方法。我们比较我们的结果冻融与标准有孔虫加工技术，包括使用过氧化氢。冻融处理增加了泥岩解聚的程度，并没有导致有孔虫的破坏或溶解。在冻融法之后，用白色酒精和六偏磷酸钠处理有助于有孔虫从解聚的粘土中分离，并且是压力洗涤的两倍有效。用过氧化氢处理的样本含有受损的微体化石和脆弱的钙质有孔虫的代表性不足。许多其他研究硬结泥岩使用过氧化氢提取有孔虫，这可能会导致明显的贫瘠间隔。本文介绍的冻融法是一种低成本、低风险、成功的从硬结泥岩中分离和提取钙质微体化石的方法。我们预计我们的方法可能与其他化石群有关，值得进一步发展。
Microfossil extraction from indurated mudrocks is widely acknowledged as challenging, especially for foraminifera. Here we report development of the freeze–thaw extraction method through the addition of rapid heating, detergent and ultrasound stages. We use indurated mudrock samples from the Toarcian (Early Jurassic) of Yorkshire, UK to assess the effectiveness and develop the freeze–thaw method. We compare our results from freeze–thaw with those from standard foraminifera processing techniques, including the use of hydrogen peroxide. Processing by freeze–thaw increased the degree of mudrock disaggregation and resulted in no damage or dissolution of foraminifera. Following the freeze–thaw method with treatment in white spirit and sodium hexametaphosphate aided the separation of foraminifera from the disaggregated clays and was twice as efficient as pressure washing. Samples processed with hydrogen peroxide contained damaged microfossils and an under representation of delicate calcareous foraminifera. Many other studies of indurated mudrocks have used hydrogen peroxide to extract foraminifera, and this might have resulted in apparently barren intervals. The freeze–thaw method outlined here provides a low-cost, low-risk and successful method of disaggregating and extracting calcareous microfossils from indurated mudrocks. We anticipate our method may be relevant for other fossil groups and merits further development.