Universität zu Köln

Garcia-Gallardo, Angela ORCID: 0000-0001-8802-7512, Grunert, Patrick and Piller, Werner E. ORCID: 0000-0003-2808-4720 (2018). Variations in Mediterranean-Atlantic exchange across the late Pliocene climate transition. Clim. Past., 14 (3). S. 339 - 351. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1814-9332

Full text not available from this repository.

Abstract

Mediterranean-Atlantic exchange through the Strait of Gibraltar plays a significant role in the global ocean-climate dynamics in two ways. On one side, the injection of the saline and warm Mediterranean Outflow Water (MOW) contributes to North Atlantic deep-water formation. In return, the Atlantic inflow is considered a sink of less saline water for the North Atlantic Ocean. However, while the history of MOW is the focus of numerous studies, the Pliocene Atlantic inflow has received little attention so far. The present study provides an assessment of the Mediterranean-Atlantic exchange with a focus on the Atlantic inflow strength and its response to regional and global climate from 3.33 to 2.60 Ma. This time interval comprises the mid-Pliocene warm period (MPWP; 3.29-2.97 Ma) and the onset of the Northern Hemisphere glaciation (NHG). For this purpose, gradients in surface delta O-18 records of the planktonic foraminifer Globigeri-noides ruber between the Integrated Ocean Drilling Program (IODP) Hole U1389E (Gulf of Cadiz) and Ocean Drilling Program (ODP) Hole 978A (Alboran Sea) have been evaluated. Interglacial stages and warm glacials of the MPWP revealed steep and reversed (relative to the present) W-E delta O-18 gradients suggesting a weakening of MediterraneanAtlantic exchange likely caused by high levels of relative humidity in the Mediterranean region. In contrast, periods of stronger inflow are indicated by flat delta O-18 gradients due to more intense arid conditions during the severe glacial Marine Isotope Stage (MIS) M2 and the initiation of NHG (MIS G22, G14, G6-104). Intensified Mediterranean-Atlantic exchange in cold periods is linked to the occurrence of icerafted debris (IRD) at low latitudes and a weakening of the Atlantic Meridional Overturning Circulation (AMOC). Our results thus suggest the development of a negative feedback between AMOC and exchange rates at the Strait of Gibraltar in the latest Pliocene as it has been proposed for the late Quaternary.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Garcia-Gallardo, Angela UNSPECIFIED orcid.org/0000-0001-8802-7512 UNSPECIFIED Grunert, Patrick UNSPECIFIED UNSPECIFIED UNSPECIFIED Piller, Werner E. UNSPECIFIED orcid.org/0000-0003-2808-4720 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-192916
DOI:	10.5194/cp-14-339-2018
Journal or Publication Title:	Clim. Past.
Volume:	14
Number:	3
Page Range:	S. 339 - 351
Date:	2018
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1814-9332
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CONTOURITE DEPOSITIONAL SYSTEM; SEA-SURFACE TEMPERATURES; WESTERN ALBORAN SEA; OUTFLOW WATER; EARLY PLEISTOCENE; SEASONAL VARIABILITY; NORTH-ATLANTIC; GIBRALTAR; CADIZ; GULF Multiple languages Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19291