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| Titel |
Mud volcanism and authigenic carbonates related to methane-rich fluids migration in the Tortonian-Messinian marls of the Huercal Overa basin (S.E. Spain) |
| VerfasserIn |
Catherine Pierre, Marie-Madeleine Blanc-Valleron, Jean-Marie Rouchy |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141390
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| Publikation (Nr.) |
 EGU/EGU2017-4897.pdf |
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| Zusammenfassung |
| Methane-rich fluids that are generated at depth in organic-rich deposits migrate within the
sediments to the seafloor where they are expelled to form mud volcanoes or pockmarks.
These migrating fluids are generally involved in diagenetic processes as authigenic carbonate
formation that is mediated by microbial activity and they may participate to gas
hydrate formation. These features are well-known in the present-day continental
margins but their fossil records are relatively scarce. In the Huercal Overa basin
(South East Spain), there are chaotic to roughly layered structures intruding the
Tortonian-Messinian marls that are interpreted as due to mud volcanism. Moreover, the
surrounding marls contain abundant authigenic dolomite nodules. The oxygen and carbon
isotopic compositions of these dolomites exhibit wide ranges (-1.4 < δ18O <+3.9
; -35.5 < δ13C <+5.1). They indicate that authigenic carbonate precipitation
occurred within the marly sediments due to circulation of deep fluids that might be
relatively warm as shown by the low δ18O values and where anaerobic oxidation of
methane (low δ13C values) and methanogenesis (high δ13C values) were active.
These two features, methane derived authigenic dolomites and mud volcanism, are
testifying of the intense methane-rich fluid migration in the marly deposits of the
western Mediterranean basins during the late Neogene, which was the time of major
paleoenvironmental changes in the Mediterranean sea climaxing during the Messinian
salinity crisis. |
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