Southward Migration of the Intertropical Convergence Zone Through the Holocene

TLDR

Titanium and iron concentration data from the anoxic Cariaco Basin off the Venezuelan coast provide subdecadal resolution records of hydrological cycle variations over northern South America during the past 14,000 years. These regional precipitation changes are best explained by shifts in the mean latitude of the Atlantic Intertropical Convergence Zone, potentially driven by Pacific‑based climate variability. The Cariaco Basin record shows that after the dry Younger Dryas, the Holocene thermal maximum brought increased precipitation, but since about 5400 yr BCE a trend toward drier conditions emerged with pronounced minima during 3800–2800 yr BCE and the Little Ice Age, and the record correlates strongly with distant high‑latitude Northern Hemisphere climates, evidencing global teleconnections.

Abstract

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 approximately 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.