Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6445640 | Quaternary Science Reviews | 2013 | 14 Pages |
Abstract
Oxygen isotopic data from a suite of calcite and aragonite stalagmites from cave KNI-51, located in the eastern Kimberley region of tropical Western Australia, represent the first absolute-dated, high-resolution speleothem record of the Holocene Indonesian-Australian summer monsoon (IASM) from the Australian tropics. Stalagmite oxygen isotopic values track monsoon intensity via amount effects in precipitation and reveal a dynamic Holocene IASM which strengthened in the early Holocene, decreased in strength by 4Â ka, with a further decrease from â¼2 to 1Â ka, before strengthening again at 1Â ka to years to levels similar to those between 4 and 2Â ka. The relationships between the KNI-51 IASM reconstruction and those from published speleothem time series from Flores and Borneo, in combination with other data sets, appear largely inconsistent with changes in the position and/or organization of the Intertropical Convergence Zone (ITCZ). Instead, we argue that the El Niño/Southern Oscillation (ENSO) may have played a dominant role in driving IASM variability since at least the middle Holocene. Given the muted modern monsoon rainfall responses to most El Niño events in the Kimberley, an impact of ENSO on regional monsoon precipitation over northwestern Australia would suggest non-stationarity in the long-term relationship between ENSO forcing and IASM rainfall, possibly due to changes in the mean state of the tropical Pacific over the Holocene.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geology
Authors
Rhawn F. Denniston, Karl-Heinz Wyrwoll, Victor J. Polyak, Josephine R. Brown, Yemane Asmerom, Alan D. Jr., Zachary LaPointe, Rebecca Ellerbroek, Michael Barthelmes, Daniel Cleary, John Cugley, David Woods, William F. Humphreys,