Major change in Atlantic Deep and bottom waters 700,000 yr ago

Benthonic foraminiferal evidence from the South Atlantic

Larry C Peterson, G. P. Lohmann

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

In the modern South Atlantic the transition between deep water and bottom water is marked by a clear change in the associated benthonic foraminiferal fauna. uvigerina and Globocassidulina characterize oxygen-poor Circumpolar Deep Water which has long been isolated from the surface. Planulina and miliolids are found associated with the more newly formed, oxygen-rich North Atlantic Deep Water. Antarctic Bottom Water is characterized by "Epistominella" umbonifera. Analysis of the benthonic foraminiferal faunas in two sediment cores recovered from the Vema and Hunter Channels in the western South Atlantic shows that the level of the transition between deep and bottom waters shallowed sharply about 700,000 yr ago. This rise indicates a sharp, sustained increase in the volume of bottom water flowing through the South Atlantic after this time. Prior to about 700,000 yr ago, the amount of Antarctic Bottom Water entering the western South Atlantic was greatly reduced and Circumpolar Deep Water apparently accounted for the bulk of northward flow. Production of southward-flowing North Atlantic Deep Water seems not to have been affected. The timing of this change in circulation regime suggests a possible causal link to similar changes in records of terrestrial and sea-surface climate.

Original languageEnglish (US)
Pages (from-to)26-38
Number of pages13
JournalQuaternary Research
Volume17
Issue number1
DOIs
StatePublished - 1982
Externally publishedYes

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bottom water
deep water
Antarctic Bottom Water
North Atlantic Deep Water
fauna
oxygen
sediment core
sea surface
Water
climate

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Earth-Surface Processes

Cite this

Major change in Atlantic Deep and bottom waters 700,000 yr ago : Benthonic foraminiferal evidence from the South Atlantic. / Peterson, Larry C; Lohmann, G. P.

In: Quaternary Research, Vol. 17, No. 1, 1982, p. 26-38.

Research output: Contribution to journalArticle

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