Hydrological connectivity and mixing of Lake Towuti, Indonesia in response to paleoclimatic changes over the last 60,000 years

K. M. Costa, J. M. Russell, H. Vogel, S. Bijaksana

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33 Scopus citations

Abstract

The Indo-Pacific Warm Pool (IPWP) is an important driver of global climate, but its response to and involvement in paleoclimate change is poorly constrained. We generated a new record of sediment geochemistry from Lake Towuti (2.5°S, 121.5°E), Indonesia, located in the heart of the IPWP, to investigate changes in hydrological connectivity with upstream lakes and the extent of lake mixing and oxygenation during paleoclimate changes over the last 60,000. years BP (60. ka). Lake Towuti is located at the downstream end of the Malili Lakes, a chain of large, ancient, and biologically diverse tectonic lakes occupying a geologically heterogeneous terrain in central Sulawesi, Indonesia. Major and trace element data from river and lake sediments suggest no changes in sediment provenance during the Last Glacial Maximum (LGM), indicating that some of the Malili Lakes remained hydrologically open despite a regionally drier climate. However, samples from the LGM are uniformly less enriched in trace elements than samples from the Holocene and Marine Isotope Stage 3 (MIS3), which suggests a decrease in weathering intensity during the LGM, likely in response to decreased precipitation and temperature. Changes in Fe and other redox-sensitive trace element concentrations indicate changes in water column oxygenation, with the highest oxygen availability occurring during the LGM (15-35. ka) likely due to more frequent and/or deeper mixing of Lake Towuti's water column. The glacial-interglacial trend in lake oxygenation corresponds with changes in regional precipitation and associated changes in the seasonal cycle. The high degree of faunal endemism in these lakes may be related to changes in the lake geochemistry associated with glacial-interglacial environmental variability driven by changing inputs and redox variability.

Original languageEnglish (US)
Pages (from-to)467-475
Number of pages9
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume417
DOIs
StatePublished - Jan 1 2015

Bibliographical note

Funding Information:
The authors thank Gerald Tamuntuan, Satrio Wicaksono, and Vale Base Metals for field assistance, David Murray and Joe Orchardo for laboratory assistance, and Sean Crowe for oxygen saturation data. We thank two anonymous reviewers for constructive feedback on this manuscript. This research was funded by NSF-EAR-1144623 to JMR. Research permits for this work were granted by the Indonesian Ministry of Research and Technology (RISTEK).

Publisher Copyright:
© 2014 Elsevier B.V.

Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.

Keywords

  • Indonesia
  • Redox
  • Sediment provenance
  • Tropical paleoclimate

Continental Scientific Drilling Facility tags

  • IDLE

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