Thomas, K, Herminghaus, S, Porada, H and Goehring, L ORCID: https://orcid.org/0000-0002-3858-7295, 2013. Formation of Kinneyia via shear-induced instabilities in microbial mats. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 371 (2004), p. 20120362. ISSN 1364-503X
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Abstract
Kinneyia are a class of microbially mediated sedimentary fossils. Characterized by clearly defined ripple structures, Kinneyia are generally found in areas that were formally littoral habitats and covered by microbial mats. To date, there has been no conclusive explanation of the processes involved in the formation of these fossils. Microbial mats behave like viscoelastic fluids. We propose that the key mechanism involved in the formation of Kinneyia is a Kelvin–Helmholtz-type instability induced in a viscoelastic film under flowing water. A ripple corrugation is spontaneously induced in the film and grows in amplitude over time. Theoretical predictions show that the ripple instability has a wavelength proportional to the thickness of the film. Experiments carried out using viscoelastic films confirm this prediction. The ripple pattern that forms has a wavelength roughly three times the thickness of the film. This behaviour is independent of the viscosity of the film and the flow conditions. Laboratory-analogue Kinneyia were formed via the sedimentation of glass beads, which preferentially deposit in the troughs of the ripples. Well-ordered patterns form, with both honeycomb-like and parallel ridges being observed, depending on the flow speed. These patterns correspond well with those found in Kinneyia, with similar morphologies, wavelengths and amplitudes being observed.
Item Type: | Journal article |
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Publication Title: | Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
Creators: | Thomas, K., Herminghaus, S., Porada, H. and Goehring, L. |
Publisher: | The Royal Society Publishing |
Date: | 4 November 2013 |
Volume: | 371 |
Number: | 2004 |
ISSN: | 1364-503X |
Identifiers: | Number Type 10.1098/rsta.2012.0362 DOI 24191114 PubMed ID |
Divisions: | Schools > School of Science and Technology |
Record created by: | Jonathan Gallacher |
Date Added: | 05 Sep 2016 09:51 |
Last Modified: | 18 Oct 2017 13:12 |
URI: | https://irep.ntu.ac.uk/id/eprint/28374 |
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