The oxygen isotopic composition of seawater during the last glacial maximum

Author(s): Schrag, Daniel P.; Adkins, Jess F.; McIntyre, Katherine; Alexander, Jane L.; Hodell, David A.; Charles, Christopher D.; McManus, Jerry F.
Author Affiliation(s): Primary:
Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA, United States
California Institute of Technology, United States
College of Staten Island, United States
University of Florida, United States
Scripps Institution of Oceanography, United States
Woods Hole Oceanographic Institution, United States
Volume Title: Ice sheets and sea level of the last glacial maximum
Volume Author(s): Clark, Peter U., editor; Mix, Alan C.
Source: Ice sheets and sea level of the last glacial maximum, edited by Peter U. Clark and Alan C. Mix. Quaternary Science Reviews, 21(1-3), p.331-342. Publisher: Pergamon, Oxford, United Kingdom. ISSN: 0277-3791
Note: In English. 33 refs.; illus., incl. 1 table, sketch map
Summary: High-resolution oxygen and hydrogen isotope measurements were made on pore fluids from deep-sea sediments from sites in the North and South Atlantic. The data provide direct measurements of changes in the isotopic composition of bottom waters during the Last Glacial Maximum (LGM). Results from Ocean Drilling Program (ODP) Site 981 in the North Atlantic, currently bathed in North Atlantic Deep Water (NADW) reproduces previous results from the Ceara and Bermuda Rises, constraining the glacial-interglacial change in δ18O of the deep Atlantic to be 0.7-0.8 per mil. Results from Site 984, which is located north of Site 981 and at a shallower water depth, yield a similar value (0.8 per mil), providing insight into the properties of Glacial North Atlantic Intermediate Water (GNAIW). Sites from ODP Leg 177 in the South Atlantic span the modern boundary between northern and southern sources of deep water. Data from the northern site (1088) yield a similar result to sites in the tropical and North Atlantic (0.7 per mil). At the southern site (1093), located south of the polar front, the change is substantially larger (1.1 per mil), representing the change in δ18O of southern source waters since the LGM. These results confirm previous estimates that the global average change in δ18O of seawater is 1.0±0.1 per mil. Hydrogen isotopes measured on pore fluids from three sites are consistent with the oxygen isotopes from these locations, giving further support to these results. At all sites studied, the temperature of the deep ocean during the LGM, calculated by combining the pore fluid results with oxygen isotope data from benthic foraminifera, was within 1°C of the freezing point of seawater. Abstract Copyright (2002) Elsevier, B.V.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Benthic taxa; Bottom currents; Cenozoic; Currents; Deglaciation; Foraminifera; Glacial geology; Glaciation; Holocene; Invertebrata; Isotope ratios; Isotopes; Last glacial maximum; Leg 154; Leg 162; Leg 172; Leg 177; Marine sediments; Microfossils; Models; North Atlantic; North Atlantic Deep Water; Numerical models; O-18/O-16; ODP Site 1063; ODP Site 1088; ODP Site 1093; ODP Site 925; ODP Site 981; ODP Site 984; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleotemperature; Pleistocene; Pore water; Protista; Quaternary; Sediments; Stable isotopes
Coordinates: N552838 N552838 W0143903 W0143903
N612532 N612532 W0240457 W0240457
N334111 N334111 W0573654 W0573654
N041215 N041216 W0432920 W0432922
S410810 S410810 E0133346 E0133346
S495835 S495835 E0055156 E0055156
Record ID: 2002011354
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands