Multi-proxy validation of glacial-interglacial rainfall variations in southwest Sulawesi

Alena K. Kimbrough*, Michael K. Gagan, Gavin B. Dunbar, Wahyoe S. Hantoro, Chuan Chou Shen, Hsun Ming Hu, Hai Cheng, R. Lawrence Edwards, Hamdi Rifai, Bambang W. Suwargadi

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)

    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.

    Original languageEnglish
    Article number210
    JournalCommunications Earth and Environment
    Volume4
    Issue number1
    DOIs
    Publication statusPublished - Dec 2023

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