The vacuum cast embedding and X-ray micro-computed tomography as standard methods to visualise bioerosion traces in Serpulid tubes

0558595 - GLÚ 2023 RIV SK eng A - Abstract
Kočová Veselská, Martina - Kočí, T. - Jäger, M. - Heřmanová, Z. - Bruthansová, J. - Mikuláš, Radek
The vacuum cast embedding and X-ray micro-computed tomography as standard methods to visualise bioerosion traces in Serpulid tubes.
Field Trip Guide and Abstracts Book. Bratislava: Štátny geologický ústav Dionýza Štúra, 2022 - (Fekete, K.). s. 143-145. ISBN 978-80-8174-064-0.
[Slovak-Czech-Polish Paleontological Conference /21./. 23.05.2022-25.05.2022, Bratislava]
Institutional support: RVO:67985831
Keywords : polychaetes * trace fossils * 3D visualisation * late Cenomanian * early Turonian
OECD category: Paleontology
https://www.geology.sk/wp-content/uploads/2022/06/PAL_CON_abstracts_book_FINAL.pdf

Bioerosion in tubes of serpulid polychaetes from the late Cenomanian and early Turonian of the Bohemian Cretaceous Basin in the Czech Republic and the late Cenomanian of Le Mans region in France were studied by combination of non-invasive micro-computed tomography and invasive vacuum cast-embedding technique producing polymer resin casts. Our study shows how different imaging techniques bias the description and diagnosis of bioerosion inside tiny serpulid tubes (0.5–0.8 mm in diameter). The great benefits of micro-CT are its non-destructive nature and ability to display empty borings (air space) or borings filled with dense matrix. The results, however, depend critically on the contrast in density and atomic number between the fossil material and the respective boring infilling. Moreover, resolutions of less than 5 μm cannot be effectively achieved. Vacuum cast-embedding is the process of filling tunnels with epoxy resin under vacuum conditions, and dissolving the substrate via treatment with diluted hydrochloric acid. This method is thus unsuitable for poorly soluble (e.g. silicified, pyritized) substrates, boreholes filled with non-porous material, and due to its destructive nature for unique or rare specimens. Nevertheless, the SEM images of the resulting casts have significantly better resolution than micro-CT and thus enable to display and quantify the most delicate morphological features such as microborings as well as details of macroborings.

Permanent Link: https://hdl.handle.net/11104/0332849