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| Titel |
Tracking climate variability in the western Mediterranean during the Late Holocene: a multiproxy approach |
| VerfasserIn |
V. Nieto-Moreno, F. Martinez-Ruiz, S. Giralt, F. Jiménez-Espejo, D. Gallego-Torres, M. Rodrigo-Gámiz, J. Garcia-Orellana, M. Ortega-Huertas, G. J. Lange |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 7, no. 4 ; Nr. 7, no. 4 (2011-12-13), S.1395-1414 |
| Datensatznummer |
250004695
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| Publikation (Nr.) |
 copernicus.org/cp-7-1395-2011.pdf |
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| Zusammenfassung |
| Climate variability in the western Mediterranean is reconstructed for the
last 4000 yr using marine sediments recovered in the west Algerian-Balearic
Basin, near the Alboran Basin. Fluctuations in chemical and mineralogical
sediment composition as well as grain size distribution are linked to
fluvial-eolian oscillations, changes in redox conditions and paleocurrent
intensity. Multivariate analyses allowed us to characterize three main
groups of geochemical and mineralogical proxies determining the sedimentary
record of this region. These three statistical groups were applied to
reconstruct paleoclimate conditions at high resolution during the Late
Holocene. An increase in riverine input (fluvial-derived elements – Rb/Al,
Ba/Al, REE/Al, Si/Al, Ti/Al, Mg/Al and K/Al ratios), and a decrease in
Saharan eolian input (Zr/Al ratio) depict the Roman Humid Period and the
Little Ice Age, while drier environmental conditions are recognized during
the Late Bronze Age-Iron Age, the Dark Ages and the Medieval Climate
Anomaly. Additionally, faster bottom currents and more energetic
hydrodynamic conditions for the former periods are evidenced by enhanced
sortable silt (10-63 μm) and quartz content, and by better oxygenated
bottom waters – as reflected by decreasing redox-sensitive elements (V/Al,
Cr/Al, Ni/Al and Zn/Al ratios). In contrast, opposite paleoceanographic
conditions are distinguished during the latter periods, i.e. the Late Bronze
Age-Iron Age, the Dark Ages and the Medieval Climate Anomaly. Although no Ba
excess was registered, other paleoproductivity indicators (total organic
carbon content, Br/Al ratio, and organometallic ligands such as U and Cu)
display the highest values during the Roman Humid Period, and together with
increasing preservation of organic matter, this period exhibits by far the
most intense productivity of the last 4000 yr. Fluctuations in detrital
input into the basin as the main process managing deposition, reflected by
the first eigenvector defined by the Principal Component Analyses, point to
solar irradiance and the North Atlantic Oscillation variability as the main
driving mechanisms behind natural climate variability over decadal to
centennial time-scales for the last 4000 yr. |
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