Evidence of a full West Antarctic Ice Sheet back to the early Oligocene: insight from double dating of detrital apatites in Ross Sea sediments. |
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| Authors: | Valerio Olivetti Maria Laura Balestrieri Federico Rossetti Stuart N Thomson Franco M Talarico Massimiliano Zattin |
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| Institution: | 1. Aix‐Marseille Université, CNRS, IRD, CEREGE UM34, Aix en Provence, France;2. CNR, Istituto di Geoscienze e Georisorse, U.O.S. Firenze, Florence, Italy;3. Department of Sciences, Geological Sciences, University of Roma Tre, Rome, Italy;4. Department of Geosciences, University of Arizona, Tucson, AZ, USA;5. Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy;6. Department of Geosciences, University of Padova, Padova, Italy |
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| Abstract: | The West Antarctic Ice Sheet is the most unstable component of the Antarctic cryosphere. Its fluctuations are well documented since the Pliocene, but its behaviour over the last 35 Ma is more controversial, particularly during periods of past high global pCO2 values similar to those predicted in future global climate scenarios. Here, we present new U–Pb dating of detrital apatite grains (previously dated by the fission‐track method) from Cape Roberts Project Oligocene to Pliocene marine sediments in the Ross Sea. Two past ice‐flow patterns were identified: one formed by outlet glaciers sourcing short‐travelled apatites and one, northerly directed, bringing far‐travelled apatite grains. The latter provides the first robust physical evidence for the presence and repeated expansion of an Oligocene West Antarctic Ice Sheet. |
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