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| Titel |
Reconstruction of sea surface water dynamics in the North Atlantic during the Mid-Pleistocene (~540-400 ka) |
| VerfasserIn |
Marta Martinez-Sanchez, José-Abel Flores, Eliana Palumbo, Montserrat Alonso-Garcia, Francisco-Javier Sierro, Filomena Ornella Amore |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095711
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| Publikation (Nr.) |
 EGU/EGU2014-11179.pdf |
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| Zusammenfassung |
| This study focuses on the reconstruction of global changes in the North Atlantic Current
(NAC) and its ramifications, the Irminger Current (IC) and the Portugal Current (PC). For this
aim, coccolithophore assemblages have been studied at IODP Site U1314 (57ºN) and
integrated with published and unpublished data from MD03-2699 (39ºN) core (Amore et al.,
2012; Palumbo et al., 2013). The sampling resolution used in this study is about 1-2 ka and
ranging MIS 14 to MIS11 (~540-400 ka).
At both regions, the coccolithophore assemblage is characterized by high abundance of
small Gephyrocapsa. Since these species proliferate under eutrophic conditions, their
abundance variations have been discussed as indicative of paleoproductivity changes and
linked to the IC in IODP Site U1314, whereas in the MD03-2699 is related to the
PC.
Statistical analyses have been applied to numerical data concerning abundance of
different taxonomic groups of coccolithophores and planktonic foraminifers. Particularly, in
order to evaluate phase relationships between time series, cross correlation analysis has been
applied. Through the application of REDFIT package implemented in PAST software, the
main periodicities of the studied time series have been investigated. In order to better
appreciate the contribution of spectral signals, main periodic components have
been extrapolated applying filtering functions, implemented in Matlab statistic
toolbox, and the sinusoidal regression tool, implemented in PAST software. The main
orbital forcing acting on the distribution of small and medium sized Gephyrocapsa,
Coccolithus pelagicus sub. pelagicus and Neogloboquadrina pachyderma (sin), is
related to eccentricity. Overprinted, precession cycles have been observed provoking
fluctuations of this time-entity in the IC and PC, demonstrating a close behaviour as result
of a general fluctuation of the NAC and thermohaline dynamics (Alonso-García,
2011).
REFERENCES:
Montserrat Alonso-Garcia, Francisco J. Sierro, José A. Flores, Arctic front shifts
in the subpolar North Atlantic during the Mid-Pleistocene (800–400ka) and
their implications for ocean circulation, Palaeogeography, Palaeoclimatology,
Palaeoecology,Volume 311, Issues 3–4, 15 November 2011, Pages 268-280,
http://dx.doi.org/10.1016/j.palaeo.2011.09.004.
F.O.
Amore, J.A. Flores, A.H.L. Voelker, S.M. Lebreiro, E. Palumbo, F.J. Sierro, A
Middle Pleistocene Northeast Atlantic coccolithophore record: Paleoclimatology
and paleoproductivity aspects, Marine Micropaleontology, Volumes 90–91, June
2012, Pages 44-59, , http://dx.doi.org/10.1016/j.marmicro.2012.03.006.
E. Palumbo, J.A. Flores, C. Perugia, Z. Petrillo, A.H.L. Voelker, F.O. Amore,
Millennial scale coccolithophore paleoproductivity and surface water changes
between 445 and 360ka (Marine Isotope Stages 12/11) in the Northeast Atlantic,
Palaeogeography, Palaeoclimatology, Palaeoecology, Volumes 383–384, August
2013, Pages 27-41, http://dx.doi.org/10.1016/j.palaeo.2013.04.024. |
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