Podrobnosti záznamu

    An acid-free method of microfossil extraction from clay-rich lithologies using the surfactant Rewoquat
    Ferrová, Lenka
    Jarochowska, Emilia
    Munnecke, Axel
    Sklenář, Jan
    Tonarová, Petra
    Vodrážková, Stanislava
Typ dokumentu
    článek v periodiku
Zdrojový dokument - seriál
    Palaeontologia Electronica
    Roč. 16, č. 3
Výraz tezauru
    calcareous fossils, organic-walled microfossils, phosphatic microfossils, clay dispersion, acid digestion, three-dimensional preservation
Klíčové slovo
Abstrakt (anglicky)
   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 t
   o recover calcareous in addition to organic-walled fossils. The yield and reservation 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.
    Česká geologická služba
Kód přispěvatele
    ČGS (RIV)
Zdrojový formát
Datum importu
    15. 10. 2014