Southern Ocean upper water column structure over the last 140 kyr with emphasis on the glacial terminations

Author(s): Mortyn, P. Graham; Charles, Christopher D.; Hodell, David A.
Author Affiliation(s): Primary:
Scripps Institution of Oceanography, Fresno, CA, United States
University of Florida, Department of Geological Sciences, La Jolla, CA, United States
Volume Title: From process studies to reconstruction of the palaeoenvironment; advances in palaeoceanography
Volume Author(s): Ganssen, Gerald, editor
Source: Global and Planetary Change, 34(3-4), p.241-252; XXV assembly of the European Geophysical Society, special session on From process studies to reconstruction of the palaeoenvironment; advances in palaeoceanography, Nice, France, April 25-29, 2000, edited by Gerald Ganssen. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0921-8181
Note: In English. 33 refs.; illus., incl. sketch map
Summary: We use δ18O and δ13C isotopic records from both shallow- and deep-dwelling planktonic foraminiferal species to describe the transition of surface water column structure over the last two glacial terminations in the Atlantic sector of the Southern Ocean between 41°S-50°S. The δ18O differences between deep- and shallow-dwelling foraminifera are typically less pronounced before and during a termination than they are following a termination. Additionally, δ13C minima occur during terminations that may be linked to changes in thermohaline circulation mode. These observations collectively point toward water column structural changes that vary from relatively unstratified to relatively stratified during the course of a typical climate transition. The data can potentially be explained by southward retreats of surface water masses that previously advanced to the north during a typical glacial (i.e. frontal migration). Some of the δ18O phenomena can also be explained by subduction, entrainment, and advection of continental ice meltwater from higher latitudes. In either case, the glacial subantarctic between 41°S-50°S was less thermally stratified than it is today. Abstract Copyright (2002) Elsevier, B.V.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Antarctic Ocean; Biochemistry; C-13/C-12; Carbon; Cenozoic; Climate change; Cores; Deep-water environment; Foraminifera; Geochemistry; Glacial environment; Glacial extent; Glaciomarine environment; Globigerina; Globigerina bulloides; Globigerinacea; Globigerinidae; Globorotalia; Globorotalia inflata; Globorotalia truncatulinoides; Globorotaliidae; Hydrochemistry; Invertebrata; Isotope ratios; Isotopes; Leg 177; Marine environment; Marine sediments; Microfossils; Neogloboquadrina; Neogloboquadrina pachyderma; O-18/O-16; ODP Site 1089; ODP Site 1093; Ocean Drilling Program; Ocean circulation; Oxygen; Paleo-oceanography; Paleocirculation; Paleoclimatology; Planktonic taxa; Protista; Quaternary; Rotaliina; Sea water; Sediments; Shallow-water environment; Southern Ocean; Stable isotopes; Statistical analysis; Stratification; Subantarctic regions; Thermohaline circulation; Time series analysis; Upper Quaternary
Coordinates: S405611 S405611 E0095338 E0095338
S495835 S495835 E0055156 E0055156
Record ID: 2003008115
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands