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| Titel |
Mediterranean Outflow Water at the Pliocene/Pleistocene transition: New stratigraphic constraints from IODP Site U1389 (Gulf of Cadiz, IODP Expedition 339) |
| VerfasserIn |
Patrick Grunert, Barbara Balestra, Gerald Auer, José-Abel Flores, Carl Richter, Ángela Garcia Gallardo, Ulla Röhl, Werner E. Piller  |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250132012
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| Publikation (Nr.) |
 EGU/EGU2016-12474.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
and the transition into the Pleistocene ice house climate. Integrated geophysical,
micropalaeontological and geochemical proxy records of the recovered sediments imply
major changes in MOW strength over the studied interval. However, to consider these data in
a broader paleoceanographic and paleoclimatic context, a well-constrained age model is
essential. New bio-, chemo-, magnetostratigraphic data and XRF core-scanning suggest that
the shipboard age model for the site has to be reconsidered as major changes in the
depositional environment have not been recognized in the original, comparably low
resolution data-sets.
While the new, high-resolution biostratigraphic data confirm the overall time frame of 2.6
to 3.6 Myrs for the studied interval, they also indicate that the last occurrence of
Discoaster tamalis in the succession should be reconsidered. New palaeomagnetic data
constrain the Gauss normal chron and its subchrons more accurately. Finally, a
high-resolution δ18O-record of the planktic foraminifer Globigerinoides ruber allows the
identification of many marine isotopic chrons, further refining the stratigraphic
framework.
Cyclic patterns are recognized in the CaCO3 and TOC contents as well as Ca/Ti- and
Zr/Al-ratios. A preliminary cyclostratigraphic analysis of these records in well-recovered
intervals suggests an interplay of obliquity and precessional forcing reflected in a change
from deposits strongly influenced by terrestrial input (3.0-2.8 Myrs) to deposits strongly
affected by MOW (2.8-2.6 Myrs).
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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