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Development of freeze-thaw processing technique for disaggregation of indurated mudrocks and enhanced recovery of calcareous microfossils

Kennedy, Alice E. and Coe, Angela L. (2014). Development of freeze-thaw processing technique for disaggregation of indurated mudrocks and enhanced recovery of calcareous microfossils. Journal of Micropalaeontology, 33(2) pp. 193–203.

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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.

Item Type: Journal Item
Copyright Holders: 2014 The Authors
ISSN: 2041-4978
Project Funding Details:
Funded Project NameProject IDFunding Body
PhD studentshipNot SetNERC (Natural Environmental Research Council
Keywords: foraminifera; hydrogen peroxide; freeze–thaw; mudrocks; microfossil extraction
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 52807
Depositing User: Angela Coe
Date Deposited: 08 Jan 2018 10:22
Last Modified: 09 Dec 2018 23:19
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