New insights into upper MOW variability over the last 150 kyr from IODP 339 Site U1386 in the Gulf of Cadiz

Type Article
Date 2016-07
Language English
Author(s) Kaboth Stefanie1, Bahr Andre2, Reichart Gert-Jan1, 3, Jacobs Bram1, Lourens Lucas J.1
Affiliation(s) 1 : Univ Utrecht, Dept Earth Sci, Fac Geosci, Heidelberglaan 2, NL-3584 CS Utrecht, Netherlands.
2 : Heidelberg Univ, Inst Earth Sci, Neuenheimer Feld 234, D-69120 Heidelberg, Germany.
3 : Royal Netherlands Inst Sea Res NIOZ, POB 59, NL-1790 AB Den Burg, Texel, Netherlands.
Source Marine Geology (0025-3227) (Elsevier Science Bv), 2016-07 , Vol. 377 , P. 136-145
DOI 10.1016/j.margeo.2015.08.014
WOS© Times Cited 30
Keyword(s) Mediterranean outflow, Glacial-interglacial variability, Sapropel, Heinrich events, Gulf of Cadiz

The upper Mediterranean Outflow Water (MOW) paleo-oceanographic history in the Gulf of Cadiz is poorly constrained due to the lack of high-resolution records that pre-date the last glaciation. Existing proxy records concentrate on MOW variability along the middle slope of the Gulf of Cadiz. Here we present a continuous high-resolution benthic foraminifera delta O-18 record from the upper MOW core at IODP Expedition 339 Site U1386 in the Gulf of Cadiz of the past 150,000 years. Based on delta O-18, grain-size and Zr/AI variability comparison of our results with existing Mediterranean Sea (MD01-2472, MD95-2043), open ocean (LR04) and Gulf of Cadiz (MD99-2339) records we have gathered new insights into the evolution of the upper MOW core on glacial interglacial timescales. The influence of the upper MOW at Site U1386 was strongest during MIS 5 and MIS 1. Similar delta O-18 variability can be seen in the Levantine Intermediate Water (LIW) originating from the Levantine Basin of the Eastern Mediterranean Sea. We found clear indication for a vertical shift of the MOW from the upper to the middle slope of the Gulf of Cadiz during sea level lowstands coinciding with MIS 4 and MIS 2 but also during MIS 3. Additionally, our results indicate an increased upper MOW flow correlated with Heinrich Events 7 to 10 and the Younger Dryas, and also inversely relate to precession-forced monsoonal freshwater inputs into the Eastern Mediterranean. In the context of Sapropel formation, we could not find conclusive evidence of the proposed MOW shutdown in our data. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.

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