Articles | Volume 13, issue 8
Clim. Past, 13, 1023–1035, 2017
https://doi.org/10.5194/cp-13-1023-2017
Clim. Past, 13, 1023–1035, 2017
https://doi.org/10.5194/cp-13-1023-2017

Research article 17 Aug 2017

Research article | 17 Aug 2017

Mediterranean Outflow Water variability during the Early Pleistocene

Stefanie Kaboth1,2, Patrick Grunert3, and Lucas Lourens2 Stefanie Kaboth et al.
  • 1Department of Earth Sciences, National Taiwan University, No 1. Sec. 4 Roosevelt Road, 106 Taipei City, Taiwan
  • 2Department of Earth Sciences, Utrecht University, Heidelberglaan 2, 3584 CS, Utrecht, the Netherlands
  • 3Institute of Earth Sciences, University of Graz, NAWI Graz, Heinrichstraße 26, 8010 Graz, Austria

Abstract. Gaining insights into the evolution of Mediterranean Outflow Water (MOW) during the Early Pleistocene has been so far hampered by the lack of available palaeoclimatic archives. Here we present the first benthic foraminifera stable oxygen and carbon isotope records and grain-size data from IODP Expedition 339 Site U1389 presently located within the upper core of the MOW in the Gulf of Cadiz for the time interval between 2.6 and 1.8 Ma. A comparison with an intermediate water mass record from the Mediterranean Sea strongly suggest an active MOW supplying Site U1389 on glacial–interglacial timescales during the Early Pleistocene. We also find indication that the increasing presence of MOW in the Gulf of Cadiz during the investigated time interval aligns with the progressive northward protrusion of Mediterranean sourced intermediate water masses into the North Atlantic, possibly modulating the intensification of the North Atlantic Meridional Overturning Circulation at the same time. Additionally, our results suggest that MOW flow strength was already governed by precession and semi-precession cyclicity during the Early Pleistocene against the background of glacial–interglacial variability.

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Short summary
This study is devoted to reconstructing Mediterranean Outflow Water (MOW) variability and the interplay between the Mediterranean and North Atlantic climate systems during the Early Pleistocene. We find indication that the increasing production of MOW aligns with the intensification of the North Atlantic overturning circulation, highlighting the potential of MOW to modulate the North Atlantic salt budget. Our results are based on new stable isotope and grain-size data from IODP 339 Site U1389.