Changes in late Pleistocene mid-water mass properties of the Gulf of Mexico

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6453509

Joyce, J E; WIlliams, D F

Micropaleontological and geochemical studies were carried out on a piston core taken from 1600 m in the northwestern Gulf of Mexico (GOM). The carbon isotope record indicates that only at approx. 78,000 year B.P. was the apparent oxygen utilization (AOU) of the mid waters equal to that of the present, otherwise, all delta/sup 13/C values are more negative during the last 130,000 years. AOU values (derived from benthic-delta/sup 13/C) from some intervals exceed the present-day AOU by approx. 0.17 mol/m/sup 3/, suggesting a > twofold increase in AOU. While an increase in mid-water mass residence time, resulting from a decrease in the production of North Atlantic Deep Water (NADW), may have contributed to an increased AOU, calculations suggest that it cannot account for the entire change. The authors suggest that the depth range of Antarctic Intermediate Water in the GOM may have extended by at least 600 m below its present-day maximum of approx. 1000 m. Increases in the relative percentage of the benthic foraminifera Uvigerina peregrina are correlatable with negative benthic-delta/sup 13/C events during oxygen isotope stages 2, 4, 5, and 6. This suggests that U. peregrina may have been responding to changes in the dissolved oxygen content of the mid waters. No correlation was found between the distribution of U. peregrina and sedimentary organic carbon. For the last 22,000 years, there is a good correlation between the benthic-delta/sup 13/C records from the North Atlantic and the GOM, and between the U. peregrina records from the two basins.

• Research Organization: Union Oil Company, Houston, TX (USA)
• OSTI ID: 6453509
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ANIMALS
ATLANTIC OCEAN
CARBON ISOTOPES
CARIBBEAN SEA
CENOZOIC ERA
CHEMICAL COMPOSITION
CHEMISTRY
DRILL CORES
ELEMENTS
FORAMINIFERA
GEOCHEMISTRY
GEOLOGIC AGES
GULF OF MEXICO
INVERTEBRATES
ISOTOPE RATIO
ISOTOPES
MICROORGANISMS
NONMETALS
OXYGEN
PALEONTOLOGY
PLEISTOCENE EPOCH
PROTOZOA
QUATERNARY PERIOD
SARCODINA
SEA BED
SEAS
SEDIMENTS
SURFACE WATERS
WATER CHEMISTRY