Southward Migration of the Intertropical Convergence Zone Through the Holocene
Gerald H. Haug,1
Konrad A. Hughen,2
Daniel M. Sigman,3
Larry C. Peterson,4
Ursula Röhl5
Titanium and iron concentration data from the anoxic Cariaco Basin,
off the Venezuelan coast, can be used to infer variations in the
hydrological cycle over northern South America during the past 14,000 years with subdecadal resolution. Following a dry Younger Dryas, a
period of increased precipitation and riverine discharge occurred
during the Holocene "thermal maximum." Since ~5400 years ago, a
trend toward drier conditions is evident from the data, with
high-amplitude fluctuations and precipitation minima during the time
interval 3800 to 2800 years ago and during the "Little Ice Age."
These regional changes in precipitation are best explained by shifts in
the mean latitude of the Atlantic Intertropical Convergence Zone
(ITCZ), potentially driven by Pacific-based climate variability.
The Cariaco Basin record exhibits strong correlations with climate
records from distant regions, including the high-latitude Northern
Hemisphere, providing evidence for global teleconnections among
regional climates.
1 Department of Earth Sciences,
Eidgenössische Technische Hochschule-Zentrum, CH-8092
Zürich, Switzerland.
2 Woods Hole
Oceanographic Institution, Woods Hole, MA 02543, USA.
3 Department of Geosciences, Princeton University,
Princeton, NJ 08544, USA.
4 Rosenstiel School of
Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA.
5 Fachbereich Geowissenschaften,
Universität Bremen, D-28334 Bremen, Germany.
