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ABSTRACT: Thorium-230 ages and oxygen isotope ratios of stalagmites from Dongge Cave, China, characterize the Asian Monsoon and low-latitude precipitation over the past 160,000 years. Numerous abrupt changes in 18O/16O values result from changes in tropical and subtropical precipitation driven by insolation and millennial-scale circulation shifts. The Last Interglacial Monsoon lasted 9.7 ± 1.1 thousand years, beginning with an abrupt (less than 200 years) drop in 18O/16O values 129.3 ± 0.9 thousand years ago and ending with an abrupt (less than 300 years) rise in 18O/16O values 119.6 ± 0.6 thousand years ago. The start coincides with insolation rise and measures of full interglacial conditions, indicating that insolation triggered the final rise to full interglacial conditions. |
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| Fig. 2 (top) d18O values of Dongge Cave stalagmites D3 (blue) and D4 (green) and Hulu Cave stalagmites {purple, including H82, MSD, and MSL}. Dongge and Hulu Cave 230Th ages and 2 sigma errors are color-coded by stalagmite (errors for dates <20 ka are equal to or less than the error bars). Summer insolation (integrated over June, July, and August) at 25°N is shown in gray. (Bottom) d18O values of Greenland ice. The d18O scale in the top section increases downward, whereas that of the bottom section increases upward. The Asian Monsoon is characterized throughout this interval by large abrupt (several years to a few centuries) shifts in d18O, which anticorrelate with millennial-scale events as observed in Greenland and with insolation. The changes in stalagmite d18O likely reflect changes in the amount of precipitation between atmospheric moisture sources and cave localities, with decreases in d18O (up in top section) corresponding to increases in precipitation integrated from source to cave site. |
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To read or view the full study, please visit the
Science website. It was published in Science, Vol. 304, Issue 5670, 575-578 , 23 April 2004 |
| DATA: Download the Data from the WDC Paleo archive.
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Contact Us National Oceanic and Atmospheric Administration 12 May 2004 |