Was the Mediterranean Sea during the Calabrian (Early Pleistocene) a low seasonality environment?


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Thomas.Brey [ at ] awi.de

Abstract

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±0.1permill (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 0.4permill and 1.1permill 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±0.1permill 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.



Item Type
Conference (Poster)
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Not peer-reviewed
Publication Status
Published
Event Details
European Geosciences Union General Assembly, 01 Apr 2017 - 01 Apr 2017, Vienna, Austria.
Eprint ID
45359
Cite as
von Leesen, G. , Beierlein, L. , Scarponi, D. , Schöne, B. R. and Brey, T. (2017): Was the Mediterranean Sea during the Calabrian (Early Pleistocene) a low seasonality environment? , European Geosciences Union General Assembly, Vienna, Austria, April 2017 - April 2017 .


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