Mid-holocene climate change in Lake Bosumtwi, Ghana

James Russell, Michael R. Talbot, Brian J. Haskell

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66 Scopus citations

Abstract

Lake Bosumtwi is one of the most widely studied palaeoclimate archives in West Africa. Results from numerous AMS 14C dates of samples from four piston cores from Lake Bosumtwi show that an abrupt sedimentary transition from a mid-Holocene sapropel to calcareous laminated muds occurred at about 3200 cal yr B.P. High-resolution analyses of the nitrogen isotopic composition of organic matter across this transition confirm its abrupt nature, and suggest that the change may signal a step toward increased aridity and intensified surface winds that affected western equatorial Africa from Ghana to the Congo basin. Northern and Eastern Africa experienced a similar abrupt shift toward aridity during the late Holocene, but at about 5000 cal yr B.P., a difference in timing that illustrates the regional nature of climate changes during the Holocene and the importance of feedback mechanisms in regulating Holocene climate variability. Furthermore, an abrupt change at about 3000 cal yr B.P. occurs at several sites adjacent to the tropical and subtropical Atlantic, which may hint at major changes in the surface temperatures of the tropical Atlantic and/or Pacific at this time.

Original languageEnglish (US)
Pages (from-to)133-141
Number of pages9
JournalQuaternary Research
Volume60
Issue number2
DOIs
StatePublished - Sep 2003

Bibliographical note

Funding Information:
We thank Dan Livingstone, John King, Jonathan Overpeck, John Peck, and Chris Scholz for the kind donations of samples from Lake Bosumtwi cores. J. Russell acknowledges the NSF Graduate Research Fellowship program for salary support. This research was supported by grants from the Graduate Research Training Group: Palaeorecords of Global Change at the University of Minnesota to J. Russell and NSF ATM 9805293 to Dr. Kerry R. Kelts. Jean Maley, Thomas C. Johnson, and an anonymous reviewer gave helpful criticisms of an earlier version of this paper. The GMS laboratory at the University of Bergen is supported by the Norwegian Research Council (NFR).

Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.

Keywords

  • Lake Bosumtwi
  • Nitrogen isotopes
  • Palaeolimnology
  • Radiocarbon
  • Tropical palaeoclimate
  • West Africa

Continental Scientific Drilling Facility tags

  • LIAF

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