New insights into the early Pliocene hydrographic dynamics and their relationship to the climatic evolution of the Mediterranean Sea G. Kontakiotis a, ⁎, V. Karakitsios a , P.G. Mortyn b,c , A. Antonarakou a , H. Drinia a , G. Anastasakis a , K. Agiadi a , N. Kafousia a , &, M. De Rafelis d,e a Faculty of Geology & Geoenvironment, School of Earth Sciences, Department of Historical Geology-Paleontology, National & Kapodistrian University of Athens, Panepistimiopolis, Zografou 15784, Greece b Institute of Environmental Science and Technology (ICTA), Universitat Autςnoma de Barcelona (UAB), Edifici Z - Carrer de les Columnes, Bellaterra 08193, Spain c Department of Geography, Universitat Autςnoma de Barcelona (UAB), Spain d Université Pierre et Marie CURIE, Institut des Sciences de la Terre de Paris UMR 7193 CNRS-UPMC, 75005 Paris, France e Géosciences Environnement Toulouse (GET), Univ. Paul Sabatier, UMR CNRS 5563, Toulouse, France abstract article info Article history: Received 26 February 2016 Received in revised form 22 June 2016 Accepted 19 July 2016 Available online 21 July 2016 One of the most enigmatic features of long-term Cenozoic climatic evolution, with some analog potential for present/future global climate change, is the last sustained warm and high-atmospheric CO 2 interval in Earth's history, which started after the end of the Messinian Salinity Crisis (5.971–5.332 Ma) in the Mediterranean Sea. We present high-resolution, astronomically-tuned climate (Mg/Ca, δ 18 O) and productivity (Ba/Ca, δ 13 C) proxy records from the planktonic foraminifera Globigerinoides obliquus in the Kalamaki section (Zakynthos Island, Greece), which sheds new light on the early Pliocene Mediterranean hydrographic dynamics, and the associated climatic transition from 5.33 to 5.11 Ma. We recognized four distinct climatic phases with variable am- plitude changes: (1) very warm climate interval prior to 5.28 Ma characterized by minimum ice volume, large salinity fluctuations, enhanced productivity, and intense river runoff, (2) stable paleoceanographic conditions from 5.28 to 5.23 Ma, which reflect a relatively warm and mesotrophic to eutrophic open-marine environment with improved ventilation, (3) a brief interval (20 ky) characterized by the most pronounced ice growth and in- tense cooling (∼ 5 °C) coupled with the abrupt decrease of ventilation and primary productivity, and (4) reinstate- ment of relatively stable conditions (warm and well-ventilated mesotrophic upper water column) in conjunction with relatively stable sea-level after 5.21 Ma. Overall, the succession of these phases provides an explanation for the more variable Mediterranean climate and stronger hydrographic variability with respect to other regions during the early Pliocene. © 2016 Elsevier B.V. All rights reserved. Keywords: “Trubi” formation Sediment cycles Stable isotopes Mg/Ca-SSTs Sea-level changes Paleoceanography 1. Introduction The Pliocene Epoch (5.33–2.58 Ma) spans a critical period in Earth history during which global climate underwent a profound transition from relatively warm conditions to the substantially cooler climate that heralded the high magnitude glacial–interglacial (G/I) oscillations of the Pleistocene. The early Pliocene is the most recent period in Earth history when the average global temperature (2.70–4.05 °C or 3–9 °C according to computer modeling (Haywood et al., 2013a, 2013b; Lunt et al., 2010) and multi-proxy (e.g. Mg/Ca, U k’ 37 ) paleothermometers (Haywood et al., 2005; Lawrence et al., 2009; Dekens et al., 2007, 2008; Medina-Elizalde et al., 2008; Seki et al., 2010; Karas et al., 2011) and sea-level (5–70 m; Miller et al., 2005, 2011; Rohling et al., 2014) were higher than today. Moreover, the atmospheric carbon dioxide concen- trations (pCO 2 ) were close to or slightly above modern values (350– 400 ppmv; Pagani et al., 2010; Seki et al., 2010; Bartoli et al., 2011). Although this time period is not an ideal analog for present or future anthropogenic climate change according to Haywood et al. (2011), it does offer an appropriate interval to understand the climatic processes of a warm, high CO 2 world and its response to the changing cryosphere. One period of geological time receiving considerable attention within the early Pliocene is the basal Pliocene, specifically that (5.33–5.00 Ma) immediately following the Messinian Salinity Crisis (MSC). The sedimentary expression of this event is widely recorded, both in land sections and in deep sea cores, showing that the transition from an evap- oritic or continental (e.g. Messinian Lago-Mare deposits) to a marine (e.g. Zanclean “Trubi” marls) environment across the Miocene/Pliocene (M/P) boundary was typified by geologically instantaneous and continuous Palaeogeography, Palaeoclimatology, Palaeoecology 459 (2016) 348–364 ⁎ Corresponding author. E-mail addresses: gkontak@geol.uoa.gr (G. Kontakiotis), vkarak@geol.uoa.gr (V. Karakitsios), graham.mortyn@uab.es (P.G. Mortyn), aantonar@geol.uoa.gr (A. Antonarakou), cntrinia@geol.uoa.gr (H. Drinia), anastasakis@geol.uoa.gr (G. Anastasakis), kagiadi@geol.uoa.gr (K. Agiadi), nkafousia@geol.uoa.gr (N. Kafousia), marc.derafelis@get.omp.eu (M. De Rafelis). http://dx.doi.org/10.1016/j.palaeo.2016.07.025 0031-0182/© 2016 Elsevier B.V. All rights reserved. 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