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| Titel |
Mediterranean Outflow Water during the late Pliocene: New stratigraphic constraints from micropaleontology and XRF core-scanning (IODP Expedition 339, Hole U1389E) |
| VerfasserIn |
Patrick Grunert, Barbara Balestra, José-Abel Flores, Ángela Garcia Gallardo, Gerald Auer, Ulla Röhl, Werner E. Piller  |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107984
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| Publikation (Nr.) |
 EGU/EGU2015-7712.pdf |
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| Zusammenfassung |
| IODP Hole U1389E, at present located in the lower core of the Mediterranean Outflow Water
(MOW) at 640m water depth in the northern Gulf of Cadiz, represents a key-site for the
understanding of changes in MOW contribution to the North Atlantic during the late Pliocene
thermal optimum and the transition into the Pleistocene ice house climate. Zr/Al ratios of the
recovered sediments as well as δ18O and Mg/Ca of benthic foraminifera imply major changes
in MOW strength in the studied interval. However, to consider these data in a broader
paleoceanographic and paleoclimatic context, a well-constrained age model is essential.
New data from calcareous nannoplankton and XRF core-scanning suggest that
the shipboard age model for the site has to be reconsidered as major changes in
sedimentation rates have not been recognized in the original comparably low resolution
data-sets.
While the new, higher-resolution biostratigraphic data confirm the overall time frame of 2.6
to 3.6 Myrs, they also imply a potential sedimentary hiatus within the Pliocene
thermal optimum and a significant increase in sedimentation rates thereafter. A
distinct cyclic pattern is recognized in the CaCO3 and TOC contents as well as
Ca/Ti ratios. Based on the estimated sedimentation rates these cycles are most likely
linked to precessional forcing, resembling cyclic changes in riverine input from
southern Spain recognized at several drill-sites at the northern shelf break. A detailed
cyclostratigraphic analysis is currently in progress to confirm the precessional signal and to
further constrain the duration of the sedimentary hiatus during the Pliocene thermal
optimum.
This study contributes to project P25831-N29 of the Austrian Science Fund (FWF) and is
financially supported by grants of ECORD and the Max Kade Foundation. |
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