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| Titel |
Reconstructing paleoceanographic conditions in the westernmost Mediterranean during the last 4.000 yr: tracking rapid climate variability |
| VerfasserIn |
V. Nieto-Moreno, F. Martinez-Ruiz, F. J. Jimenez-Espejo, D. Gallego-Torres, M. Rodrigo-Gámiz, T. Sakamoto, M. Böttcher, J. Garcia-Orellana, M. Ortega-Huertas |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250028827
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| Zusammenfassung |
| The westernmost Mediterranean (Alboran Sea basin) is a key location for paleoceanographic
and paleoclimatic reconstructions since high sedimentation rates provide ultra high-resolution
records at centennial and millennial scales. Here, we present a paleoenvironmental
reconstruction for the last 4000 yr, which is based on a multi-proxy approach that includes
major and trace element-content fluctuations and mineral composition of marine sediments.
The investigated materials correspond to several gravity and box cores recovered in the
Alboran Sea basin during different oceanographic cruises (TTR-14 and TTR-17), which have
been sampled at very high resolution. Comparative analysis of these cores allows establishing
climate oscillations at centennial to millennial scales. Although relatively more attention have
been devoted to major climate changes during the last glacial cycle, such as the Last Glacial
Maximun, deglaciation and abrupt cooling events (Heinrich and Younger Dryas), the late
Holocene has also been punctuated by significant rapid climate variability including
polar cooling, aridity and changes in the intensity of the atmospheric circulation.
These climate oscillations coincide with significant fluctuations in chemical and
mineral composition of marine sediments. Thus, bulk and clay mineralogy, REE
composition and Rb/Al, Zr/Al, La/Lu ratios provide information on the sedimentary
regime (eolian-fluvial input and source areas), Ba-based proxies on fluctuations in
marine productivity and redox sensitive elements on oxygen conditions at time of
deposition. A decrease in fluvial-derived elements/minerals (e.g., Rb, detrital mica)
takes places during the so-called Late Bronze Age-Iron Age, Dark Age, and Little
Ice Age Period. Meanwhile an increase is evidenced during the Medieval Warm
Period and the Roman Humid Period. This last trend runs parallel to a decline of
element/minerals of typical eolian source (Zr, kaolinite) with the exception of the
Roman Humid Period where Zr/Al ratio increases. These climate oscillations (wet
and dry periods) are also accompanied by changes in marine productivity rates,
as suggested by the Ba/Al ratio. Additionally, anthropic contribution during the
Industrial Period is also evidenced by a significant increase in Pb content in most recent
sediments.
Acknowledges: Projects Marcal CGL2006-13327-C04-04, Sagas CTM2005-08071-C03-01,
Ministerio MARM 200800050084447, RNM 0179, CSD2006-00041. |
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