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| Titel |
The Gela Basin pockmark field in the strait of Sicily (Mediterranean Sea): chemosymbiotic faunal and carbonate signatures of postglacial to modern cold seepage |
| VerfasserIn |
M. Taviani, L. Angeletti, A. Ceregato, F. Foglini, C. Froglia, F. Trincardi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 7 ; Nr. 10, no. 7 (2013-07-12), S.4653-4671 |
| Datensatznummer |
250018336
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| Publikation (Nr.) |
 copernicus.org/bg-10-4653-2013.pdf |
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| Zusammenfassung |
| The geo-biological exploration of a pockmark field located at ca. 800 m below sea level in
the Gela basin (Strait of Sicily, Central Mediterranean) provided a
relatively diverse chemosymbiotic community and methane-imprinted
carbonates. To date, this is the first occurrence of such a type of
specialised deep-water cold-seep communities recorded from this key region,
before documented in the Mediterranean as rather disjunct findings in its
eastern and westernmost basins. The thiotrophic chemosymbiotic organisms
recovered from this area include empty tubes of the vestimentiferan
Lamellibrachia sp., loose and articulated shells of lucinids (Lucinoma kazani, Myrtea amorpha), vesicomyids (Isorropodon perplexum), and
gastropods (Taranis moerchii). A callianassid decapod (Calliax sp.) was consistently found alive in
large numbers in the pockmark mud. Their post-mortem calcified parts mixed with molluscs
and subordinately miliolid foraminifers form a distinct type of skeletal
assemblage. Carbonate concretions display δ13C values as low as
−40‰ PDB suggesting the occurrence of light hydrocarbons
in the seeping fluids. Since none of the truly chemosymbiotic organisms was
found alive, although their skeletal parts appear at times very fresh, some
specimens have been AMS-14C dated to shed light on the historical
evolution of this site. Lamellibrachiav and Lucinoma are two of the most significant chemosymbiotic
taxa reported from various Mediterranean cold seep sites (Alboran Sea and
Eastern basin). Specimens from station MEDCOR78 (pockmark #1, Lat.
36°46´10.18" N, Long. 14°01´31.59" E, 815 m below sea level) provided
ages of 11736 ± 636 yr cal BP (Lamellibrachia sp.), and 9609.5 ± 153.5 yr cal BP (L. kazani).
One shell of M. amorpha in core MEDCOR81 (pockmark #6,
Lat 36°45´38.89" N, Long 14°00´07.58" E, 822 m below sea level) provided a sub-modern
age of 484 ± 54 yr cal BP. These ages document that fluid seepage at
this pockmark site has been episodically sustaining thiotrophic macrobenthic
communities since the end of the Younger Dryas stadial up to sub-recent
times. |
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