An acid-free method of microfossil extraction from clay-rich lithologies using the surfactant Rewoquat

Journal article
(Original article)


Publication Details

Author(s): Jarochowska E, Tonarová P, Munnecke A, Ferrová L, Sklenář J, Vodráková S
Journal: Palaeontologia Electronica
Publisher: Coquina Press
Publication year: 2013
Volume: 16
Journal issue: 3
Pages range: Article Number 7T, 16pp.
ISSN: 1094-8074
eISSN: 1532-3056
Language: English


Abstract


Marine rocks characterized by high clay content provide excellent conditions for fossil preservation, particularly for organic-walled microfossils such as retiolitid graptolites and chitinozoans. Nevertheless, the phyllosilicate minerals, which constitute the clay component, make microfossil extractions difficult. The problem results from the tendency of phyllosilicates to form aggregates in low pH values, as standard methods of microfossil extraction employ acids for rock digestion. Consequently, the use of acids for clay-rich rocks is often inefficient and time-consuming. We propose a method of rock disintegration using the surfactant Rewoquat and compare it with two commonly applied approaches: digestion in buffered acetic acid and in HCl-HF. Using examples from the Mulde Brick-clay Member from the Silurian of Gotland and the Daleje Shale from the Devonian of the Prague Basin we observed that disintegration in Rewoquat was faster (days) than digestion in acid (months), and allowed to recover calcareous in addition to organic-walled fossils. The yield and preservation was comparably good, except for conodonts, which were strongly etched after using HCl-HF. Retiolitid graptolites recovered using Rewoquat were preserved in 3D and showed a lower degree of fragmentation. The fossil content of the residue obtained using Rewoquat was higher due to dispersion of clay aggregates. For observation of delicate fossils we recommend to coat the sample with the surfactant. Application of Rewoquat can reveal the most delicate forms and growth stages, and thus provide a better insight into the ontogeny, autecology, and body size distributions of a number of fossil groups. © Paleontological Society November 2013.



FAU Authors / FAU Editors

Jarochowska, Emilia Dr.
Lehrstuhl für Paläoumwelt
Munnecke, Axel Prof. Dr.
Professur für Paläontologie (Schwerpunkt Faziesanalyse)


External institutions
Czech Geological Survey / Česká geologická služba
Univerzita Karlova v Praze / Charles University in Prague


How to cite

APA:
Jarochowska, E., Tonarová, P., Munnecke, A., Ferrová, L., Sklenář, J., & Vodráková, S. (2013). An acid-free method of microfossil extraction from clay-rich lithologies using the surfactant Rewoquat. Palaeontologia Electronica, 16(3), Article Number 7T, 16pp..

MLA:
Jarochowska, Emilia, et al. "An acid-free method of microfossil extraction from clay-rich lithologies using the surfactant Rewoquat." Palaeontologia Electronica 16.3 (2013): Article Number 7T, 16pp.

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Last updated on 2018-08-08 at 04:10