Research Article

Annually Resolved Ice Core Records of Tropical Climate Variability Over the Past ~1800 Years

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Science  04 Apr 2013:
DOI: 10.1126/science.1234210

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Ice cores from low latitudes can provide a wealth of unique information about past climate in the tropics, but they are difficult to recover and few exist. Here, we report annually resolved ice core records from the Quelccaya ice cap (5670 masl) in Peru which extend back ~1800 years and provide a high-resolution record of climate variability there. Oxygen isotopic ratios (δ18O) are linked to sea-surface temperatures in the tropical eastern Pacific, while concentrations of ammonium and nitrate document the dominant role played by the migration of the Intertropical Convergence Zone in the region of the tropical Andes. Quelccaya continues to retreat and thin: Radiocarbon dates on wetland plants exposed along its retreating margins indicate it has not been smaller for at least six millennia.

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