Validation of glacial-interglacial rainfall variations in southwest Sulawesi using Mg/Ca and δ18O in speleothems

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.

Downloads

Download Preprint

Authors

Alena K Kimbrough, Michael Gagan, Gavin Dunbar, Wahyoe Hantoro, Chuan-Chou Shen, Hsun-Ming Hu, Hai Cheng, Larry Edwards, Hamdi Rifai, Bambang W Suwargadi

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 measurements of Mg/Ca and δ18O for multiple stalagmites from southwest Sulawesi, Indonesia, that that confirm changes in rainfall amount across ice age terminations. Collectively, the stalagmites span two glacial-interglacial transitions from 380 to 330 ky BP and 230 to 170 ky BP. Mg/Ca in our slow-growing stalagmites is affected by karst infiltration rates 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. Deviations between the two proxies may reveal concurrent changes in rainfall amount and moisture-transport pathways indicative of regional monsoon circulation.

DOI

https://doi.org/10.31223/X5R054

Subjects

Atmospheric Sciences, Climate, Earth Sciences, Geochemistry, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Speleology

Keywords

Tropical speleothems, Mg/Ca, δ18O, prior calcite precipitation, Indonesia, glacial-interglacial paleoclimates, Mg/Ca, δ18O, prior calcite precipitation, Indonesia, Glacial-Interglacial, paleoclimate

Dates

Published: 2022-06-17 11:32

Last Updated: 2022-06-17 15:32

License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
The authors declare no competing interests.

Data Availability (Reason not available):
Please email Alena Kimbrough for the data spreadsheets mentioned in the manuscript and Supplementary Information.

Add a Comment

You must log in to post a comment.


Comments

There are no comments or no comments have been made public for this article.