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| Titel |
Was the Mediterranean Sea during the Calabrian (Early Pleistocene) a low seasonality environment? |
| VerfasserIn |
Gotje von Leesen, Lars Beierlein, Daniele Scarponi, Bernd R. Schöne, Thomas Brey |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250149344
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| Publikation (Nr.) |
 EGU/EGU2017-13679.pdf |
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| Zusammenfassung |
| Understanding past seasonal temperature variability in the ocean is essential to evaluate the
effects of future climate change on marine ecosystems. Here, we estimate seasonal
amplitudes and average water temperature from stable oxygen isotope (δ18Oshell) values
assuming δ18Owater values of 0.9 ± 0.1‰ (V-SMOV). Fossil valves of the bivalve Arctica
islandica were collected from three Pleistocene successions (middle-late Calabrian) in Italy.
Biostratigraphic analyses from Tacconi Quarry deposits (Rome) indicate an age between 1.6
and 1.2 Ma, while Augusta and Cutrofiano (Lecce) successions are slightly more recent (1.1
and 0.62 Ma, respectively). Prior to carbonate geochemical analysis, we checked the shells
for potential diagenetic alterations (e.g., from aragonite to calcite). Stable oxygen isotope
(δ18Oshell) profiles of eleven fossil A. islandica valves all depict a relatively low
seasonality scenario. δ18Oshell amplitudes vary between 0.4‰ and 1.1‰ implying a
reconstructed seasonal water temperature amplitude of 1.7˚ C to 4.8˚ C. The reconstructed
average water temperature for the Sicilian population (i.e., 9 valves) is 9.5 ± 0.47˚ C
for δ18Owater 0.9 ± 0.1‰ and coincides well with temperature requirements for
modern A. islandica. The low seasonality scenario (ca. 3˚ C) represented by the
shells and the low reconstructed water temperatures, colder than modern water
temperatures let to the conclusion that the shells lived during a maximum glacial
phase when relatively constant water temperatures prevailed throughout the year. |
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