Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/98215
Title: Impact of restriction of the Atlantic-Mediterranean gateway on the Mediterranean Outflow Water and eastern Atlantic circulation during the Messinian
Author: Pérez-Asensio, José N. (José Noel)
Aguirre, Julio
Schmiedl, Gerhard
Civis Llovera, Jorge
Keywords: Messinià
Foraminífers
Bentos
Bajo Guadalquivir (Andalusia)
Messinian
Foraminifera
Benthos
Bajo Guadalquivir Region (Andalusia)
Issue Date: 1-Sep-2012
Publisher: American Geophysical Union
Abstract: Messinian foraminiferal stable oxygen and carbon isotopes of the Montemayor-1 core (Guadalquivir Basin, SW Spain) have been investigated. This record is exceptional to study the Mediterranean Outflow Water (MOW) impact on the Atlantic meridional overturning circulation (AMOC) and global climate during the Messinian because the core is near the Guadalhorce Corridor, the last Betic gateway to be closed during the early Messinian. Our results allow dating accurately its closure at 6.18 Ma. Constant benthic d18O values, high difference between benthic and planktonic d18O, and low sedimentation rates before 6.18 Ma indicate the presence of a two-layer water column, with bottom winnowing due to an enhanced Mediterranean outflow current. The enhanced contribution of dense MOW to the North Atlantic Ocean likely fostered the formation of North Atlantic Deep Water (NADW). After 6.18 Ma, benthic d18O values parallel that of the global glacioeustatic curve, the difference between benthic and planktonic d18O is low, and sedimentation rates considerably increased. This indicates a good vertical mixing of the water column, interruption of the MOW, and a dominant glacioeustatic control on the isotopic signatures. According to the role of MOW in the modern Atlantic thermohaline circulation, the reduction of the MOW after the closure of the Guadalhorce Corridor might have resulted in a decreased NADW formation rate between 6.0 and 5.5 Ma weakening the AMOC and promoting northern hemisphere cooling. After the Gibraltar Strait opening, the restoration of the MOW and related salt export from the Mediterranean could have promoted an enhanced NADW formation.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1029/2012PA002309
It is part of: Paleoceanography, 2012, vol. 27, num. 3, p. 1-14
Related resource: http://dx.doi.org/10.1029/2012PA002309
URI: http://hdl.handle.net/2445/98215
ISSN: 0883-8305
Appears in Collections:Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)

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