Variations in mid-latitude North Atlantic surface water properties during the mid-Brunhes (MIS 9-14) and their implications for the thermohaline circulation

Online Access: Get full text
doi: 10.5194/cp-6-531-2010
Author(s): Voelker, Antje H. L.; Rodrigues, Teresa A.; Billups, Katharina; Oppo, Delia Wanda; McManus, Jerry F.; Stein, Rüdiger; Hefter, Jens; Grimalt, J. O.
Author Affiliation(s): Primary:
Laboratorio Nacional de Energia e Geologia, Unidade Geologia Marinha, Amadora, Portugal
Other:
CIMAR Associate Laboratory, Portugal
University of Delaware, United States
Woods Hole Oceanographic Institution, United States
Alfred-Wegener-Institut für Polar- und Meeresforschung, Federal Republic of Germany
CSIC, Institut de Diagnôstic Ambiental i Estudis de l'Aigua, Spain
Volume Title: Climate of the Past
Source: Climate of the Past, 6(4), p.531-552. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. Published in Climate of the Past Discussion: 3 June 2009, http://www.clim-past-discuss.net/5/1553/2009/cpd-5-1553-2009.html; part of special issue no. 14, Marine Isotope Stage 11, edited by Tzedakis, C., McManus, J., and Wolff, E., http://www.clim-past.net/special_issue14.html; accessed in Oct., 2010; abstract: doi:10.5194/cp-6-531-2010. 104 refs.; illus., incl. 2 tables, sketch map
Summary: Stable isotope and ice-rafted debris records from three core sites in the mid-latitude North Atlantic (IODP Site U1313, MD01-2446, MD03-2699) are combined with records of ODP Sites 1056/1058 and 980 to reconstruct hydrographic conditions during the middle Pleistocene spanning Marine Isotope Stages (MIS) 9-14 (300-540 ka). Core MD03-2699 is the first high-resolution mid-Brunhes record from the North Atlantic's eastern boundary upwelling system covering the complete MIS 11c interval and MIS 13. The array of sites reflect western and eastern basin boundary current as well as north to south transect sampling of subpolar and transitional water masses and allow the reconstruction of transport pathways in the upper limb of the North Atlantic's circulation. Hydrographic conditions in the surface and deep ocean during peak interglacial MIS 9 and 11 were similar among all the sites with relative stable conditions and confirm prolonged warmth during MIS 11c also for the mid-latitudes. Sea surface temperature (SST) reconstructions further reveal that in the mid-latitude North Atlantic MIS 11c is associated with two plateaus, the younger one of which is slightly warmer. Enhanced subsurface northward heat transport in the eastern boundary current system, especially during early MIS 11c, is denoted by the presence of tropical planktic foraminifer species and raises the question how strongly it impacted the Portuguese upwelling system. Deep water ventilation at the onset of MIS 11c significantly preceded surface water ventilation. Although MIS 13 was generally colder and more variable than the younger interglacials the surface water circulation scheme was the same. The greatest differences between the sites existed during the glacial inceptions and glacials. Then a north-south trending hydrographic front separated the nearshore and offshore waters off Portugal. While offshore waters originated from the North Atlantic Current as indicated by the similarities between the records of IODP Site U1313, ODP Site 980 and MD01-2446, nearshore waters as recorded in core MD03-2699 derived from the Azores Current and thus the subtropical gyre. Except for MIS 12, Azores Current influence seems to be related to eastern boundary system dynamics and not to changes in the Atlantic overturning circulation.
Year of Publication: 2010
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Algae; Atlantic Ocean; Blake-Bahama Outer Ridge; Brunhes Chron; C-13; C-13/C-12; Carbon; Cenozoic; Climate change; Expeditions 303/306; Foraminifera; IODP Site U1313; Integrated Ocean Drilling Program; Interglacial environment; Invertebrata; Isotope ratios; Isotopes; Leg 162; Leg 172; MIS 11; Microfossils; Mid-Atlantic Ridge; Middle Pleistocene; Nannofossils; North Atlantic; O-18/O-16; ODP Site 1056; ODP Site 1058; ODP Site 980; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleocirculation; Paleoclimatology; Paleocurrents; Plantae; Pleistocene; Protista; Quaternary; Rockall Bank; Sea-surface temperature; Stable isotopes; Thermohaline circulation; Upper Quaternary; Upwelling
Coordinates: N322906 N322906 W0761949 W0761949
N410007 N410007 W0325740 W0325740
N314124 N314124 W0752548 W0752548
N552906 N552906 W0144208 W0144208
Record ID: 2010090430
Copyright Information: GeoRef, Copyright 2020 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany