Palaeoceanographic changes in the North Atlantic during the mid-Pleistocene transition (MIS 31-19) as inferred from planktonic foraminiferal and calcium carbonate records

Online Access: Get full text
doi: 10.1111/j.1502-3885.2012.00283.x
Author(s): Hernández-Almeida, Iván; Sierro, Francisco Javier; Flores, José-Abel; Cacho, Isabel; Filippelli, Gabriel Michael
Author Affiliation(s): Primary:
University of Salamanca, Department of Geology, Salamanca, Spain
Other:
University of Barcelona, Spain
Indiana University-Purdue University Indianapolis, United States
Volume Title: Boreas
Source: Boreas, 42(1), p.140-159. Publisher: Wiley-Blackwell, Oslo, Norway. ISSN: 0300-9483 CODEN: BRESB3
Note: In English. 124 refs.; illus., incl. 1 table, sketch map
Summary: Marine sediments from the Integrated Ocean Drilling Project (IODP) Site U1314 (56.36°N, 27.88°W), in the subpolar North Atlantic, were studied for their planktonic foraminifera, calcium carbonate content, and Neogloboqudrina pachyderma sinistral (sin.) δ13C records in order to reconstruct surface and intermediate conditions in this region during the Mid-Pleistocene Transition (MPT). Variations in the palaeoceanography and regional dynamics of the Arctic Front were estimated by comparing CaCO3 content, planktonic foraminiferal species abundances, carbon isotopes and ice-rafted debris (IRD) data from Site U1314 with published data from other North Atlantic sites. Site U1314 exhibited high abundances of the polar planktonic foraminifera N. pachyderma sin. and low CaCO3 content until Marine Isotope Stage (MIS) 26, indicating a relatively southeastward position of the Arctic Front (AF) and penetration of colder and low-salinity surface arctic water-masses. Changing conditions after MIS 25, with oscillations in the position of the AF, caused an increase in the northward export of the warmer North Atlantic Current (NAC), indicated by greater abundances of non-polar planktonic foraminifera and higher CaCO3. The N. pachyderma sin. δ13C data indicate good ventilation of the upper part of the intermediate water layer in the eastern North Atlantic during both glacial and interglacial stages, except during Terminations 24/23, 22/21 and 20/1. In addition, for N. pachyderma (sin.) we distinguished two morphotypes: non-encrusted and heavily encrusted test. Results indicate that increases in the encrusted morphotype and lower planktonic foraminiferal diversity are related to the intensification of glacial conditions (lower sea-surface temperatures, sea-ice formation) during MIS 22 and 20. Abstract Copyright (2012), The Boreas Collegium.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 02 Geochemistry; 24 Surficial Geology, Quaternary Geology; Assemblages; Atlantic Ocean; Biodiversity; C-13/C-12; Calcium carbonate; Carbon; Cenozoic; Expedition 306; Expeditions 303/306; Foraminifera; Globigerinacea; IODP Site U1314; Integrated Ocean Drilling Program; Invertebrata; Isotope ratios; Isotopes; Marine environment; Marine sediments; Microfossils; Middle Pleistocene; Morphology; Neogloboquadrina; Neogloboquadrina pachyderma; North Atlantic; Northeast Atlantic; Paleo-oceanography; Paleoecology; Paleoenvironment; Planktonic taxa; Pleistocene; Productivity; Protista; Quaternary; Rotaliina; SEM data; Sediments; Stable isotopes
Coordinates: N562200 N562200 W0275300 W0275300
Record ID: 2013033536
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom