| Autor: |
T, Bosak, J W M, Bush, M R, Flynn, B, Liang, S, Ono, A P, Petroff, M S, Sim |
| Rok vydání: |
2010 |
| Předmět: |
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| Zdroj: |
Geobiology. 8(1) |
| ISSN: |
1472-4669 |
| Popis: |
Gas release in photic-zone microbialites can lead to preservable morphological biosignatures. Here, we investigate the formation and stability of oxygen-rich bubbles enmeshed by filamentous cyanobacteria. Sub-millimetric and millimetric bubbles can be stable for weeks and even months. During this time, lithifying organic-rich laminae surrounding the bubbles can preserve the shape of bubbles. Cm-scale unstable bubbles support the growth of centimetric tubular towers with distinctly laminated mineralized walls. In environments that enable high photosynthetic rates, only small stable bubbles will be enclosed by a dense microbial mesh, while in deep waters extensive microbial mesh will cover even larger photosynthetic bubbles, increasing their preservation potential. Stable photosynthetic bubbles may be preserved as sub-millimeter and millimeter-diameter features with nearly circular cross-sections in the crests of some Proterozoic conical stromatolites, while centrimetric tubes formed around unstable bubbles provide a model for the formation of tubular carbonate microbialites that are not markedly depleted in (13)C. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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