Fossilized bioelectric wire – the trace fossil Trichichnus
The trace fossil <i>Trichichnus</i> is proposed as an indicator of fossil bioelectric bacterial activity at the oxic–anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. &l...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-04-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/2301/2015/bg-12-2301-2015.pdf |
| Summary: | The trace fossil <i>Trichichnus</i> is proposed as an indicator of fossil bioelectric
bacterial activity at the oxic–anoxic interface zone of marine sediments.
This fulfils the idea that such processes, commonly found in the modern
realm, should be also present in the geological past. <i>Trichichnus</i> is an exceptional
trace fossil due to its very thin diameter (mostly less than 1 mm) and
common pyritic filling. It is ubiquitous in some fine-grained sediments,
where it has been interpreted as a burrow formed deeper than any other trace
fossils, below the redox boundary. <i>Trichichnus</i>, formerly referred to as deeply burrowed
invertebrates, has been found as remnant of a fossilized intrasediment
bacterial mat that is pyritized. As visualized in 3-D by means of X-ray
computed microtomography scanner, <i>Trichichnus</i> forms dense filamentous fabric, which
reflects that it is produced by modern large, mat-forming, sulfide-oxidizing
bacteria, belonging mostly to <i>Thioploca</i>-related taxa, which are able to house a
complex bacterial consortium. Several stages of <i>Trichichnus</i> formation, including
filamentous, bacterial mat and its pyritization, are proposed to explain an
electron exchange between oxic and suboxic/anoxic layers in the sediment.
Therefore, <i>Trichichnus</i> can be considered a fossilized "electric wire". |
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| ISSN: | 1726-4170 1726-4189 |