Multi-proxy validation of glacial-interglacial rainfall variations in southwest Sulawesi
Date
2023
Authors
Kimbrough, Alena
Gagan, Michael
Dunbar, Gavin
Hantoro, Wahyoe
Shen, Chuan-Chou
Hu, Hsun-Ming
Cheng, Hai
Edwards, Lawrence
Rifai, Hamdi
Suwargadi, Bambang W
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Nature Publishing Group
Abstract
Speleothem δ18O is widely used as a proxy for rainfall amount in the tropics on glacial-interglacial to interannual scales. However, uncertainties in the interpretation of this renowned proxy pose a vexing problem in tropical paleoclimatology. Here, we present paired multi-proxy geochemical measurements for stalagmites from southwest Sulawesi, Indonesia, and confirm changes in rainfall amount across ice age terminations. Collectively, the stalagmites span two glacial-interglacial transitions from ~380,000 to 330,000 and 230,000 to 170,000 years ago. Mg/Ca in the slow-growing stalagmites is affected by water moving through the karst and prior calcite precipitation, making it a good proxy for changes in local rainfall. When paired, Mg/Ca and δ18O corroborate prominent shifts from drier glacials to wetter interglacials in the core of the Australasian monsoon domain. These shifts in rainfall occur 4,000-7,000 years later than glacial-interglacial increases in global temperature and the associated response of Sulawesi vegetation, determined by speleothem δ13C.
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Communications Earth & Environment
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Journal article
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Open Access
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Creative Commons Attribution licence
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