Fig. 1. δ18O time series during penultimate glacial period for stalagmites
MSX (green), MSP (pink), and MSH (red). Click image for full figure.
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A penultimate glacial monsoon record from Hulu Cave and
two-phase glacial terminations
Geology
Vol. 34, Issue 3, pp. 217 - 220, March 2006
Hai Cheng1,2, R. Lawrence Edwards1, Yongjin Wang2,
Xinggong Kong2, Yanfang Ming2,
Megan J. Kelly1, Xianfeng Wang1,
Christina D. Gallup3, and Weiguo Liu4
1 Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
2 College of Geography Science, Nanjing Normal University, Nanjing 210097, China
3 Department of Geological Sciences and Large Lakes Observatory, University of Minnesota Duluth,
Duluth, Minnesota 55812, USA
4 Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710054, China
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ABSTRACT:
Oxygen isotope records of three stalagmites from Hulu Cave,
China, extend the previous high-resolution absolute-dated Hulu
Asian Monsoon record from the last to the penultimate glacial and
deglacial periods. The penultimate glacial monsoon broadly follows
orbitally induced insolation variations and is punctuated by at least
16 millennial-scale events. We confirm a Weak Monsoon Interval
between 135.5 ± 1.0 and 129.0 ± 1.0 ka, prior to the abrupt increase
in monsoon intensity at Asian Monsoon Termination II.
Based on correlations with both marine ice-rafted debris and atmospheric
CH4 records, we demonstrate that most of marine Termination
II, the full rise in Antarctic temperature and atmospheric
CO2, and much of the rise in CH4 occurred within the Weak Monsoon
Interval, when the high northern latitudes were probably
cold. From these relationships and similar relationships observed
for Termination I, we identify a two-phase glacial termination process
that was probably driven by orbital forcing in both hemispheres,
affecting the atmospheric hydrological cycle, and combined
with ice sheet dynamics.
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