Abrupt increase in east Indonesian rainfall from flooding of the Sunda Shelf ∼9500 years ago

Griffiths, Michael L., Drysdale, Russell N., Gagan, Michael K., Zhao, Jian-xin, Hellstrom, John C., Ayliffe, Linda K. and Hantoro, Wahyoe S. (2013) Abrupt increase in east Indonesian rainfall from flooding of the Sunda Shelf ∼9500 years ago. Quaternary Science Reviews, 74 273-279. doi:10.1016/j.quascirev.2012.07.006


Author Griffiths, Michael L.
Drysdale, Russell N.
Gagan, Michael K.
Zhao, Jian-xin
Hellstrom, John C.
Ayliffe, Linda K.
Hantoro, Wahyoe S.
Title Abrupt increase in east Indonesian rainfall from flooding of the Sunda Shelf ∼9500 years ago
Journal name Quaternary Science Reviews   Check publisher's open access policy
ISSN 0277-3791
1873-457X
Publication date 2013-08-15
Year available 2012
Sub-type Article (original research)
DOI 10.1016/j.quascirev.2012.07.006
Open Access Status
Volume 74
Start page 273
End page 279
Total pages 7
Place of publication Kidlington, Oxford, United Kingdom
Publisher Pergamon
Collection year 2013
Language eng
Abstract We present a precisely dated, multi-proxy stalagmite record from Liang Luar Cave, Flores (southeast Indonesia) that reveals a rapid increase in Indonesian monsoon rainfall at ∼9.5 ka. A "ramp-fitting" method for detecting statistically significant inflections in a time-series was applied to the stalagmite δ 18O, Mg/Ca, and Sr/Ca profiles to quantify the precise timing and magnitude of an abrupt increase in monsoon strength over a period of ∼350 years. Previously published lake-level records from the monsoon-affected Australian interior show a sudden intensification of the Australian monsoon at ∼14 ka. However, our records indicate that monsoon intensification in Flores occured ∼4-5 kyr later. The timing of the monsoon shift in Flores is synchronous with the rapid expansion of rainforest in northeast Australia and regional freshening of the southern Makassar Strait which, under present-day conditions, is sensitive to monsoon variability. The freshening of southern Makassar was coeval with an abrupt ∼1.5 °C cooling in the upper thermocline of the Timor Sea ∼9.5 ka, indicative of reduced surface heat transport by the Indonesian Throughflow (ITF) when the Java Sea opened during postglacial sea-level rise. This suggests that the abrupt increase in monsoon rainfall on Flores was not due to a change in the ITF - because a decrease in rainfall would be expected to accompany cooler local sea surface temperatures (SSTs) - but rather by the sudden increase in ocean surface area and/or temperature in the monsoon source region as the Sunda Shelf flooded during deglaciation. We propose that it was the abrupt intensification of the monsoon through the late deglaciation that maintained the subsequent structure of the ITF following the flooding of the Sunda Shelf at ∼9.5 ka.
Keyword Indonesia
Monsoon
Speleothem
Sunda Shelf
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online 10 August 2012

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
Centre for Microscopy and Microanalysis Publications
 
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Created: Wed, 10 Apr 2013, 13:40:12 EST by Ashleigh Paroz on behalf of School of Earth Sciences