| Abstract: |
High-resolution speleothem records from China have provided insights into the factors that control the strength of the East Asian monsoon14. Our understanding of these factors remains incomplete, however, owing to gaps in the record of monsoon history over the past two interglacialglacial cycles. In particular, missing sections have hampered our ability to test ideas about orbital-scale controls on the monsoon57, the causes of millennial-scale events8,9 and relationships between changes in the monsoon and climate in other regions. Here we present an absolute-dated oxygen isotope record from Sanbao cave, central China, that completes a Chinese cave- based record of the strength of the East Asian monsoon that covers the past 224,000 years. The record is dominated by 23,000- year-long cycles that are synchronous within dating errors with summer insolation at 656N (ref. 10), supporting the idea that tropical/subtropical monsoons respond dominantly and directly to changes in Northern Hemisphere summer insolation on orbital timescales5. The cycles are punctuated by millennial-scale strongsummer- monsoon events (Chinese interstadials1), and the new record allows us to identify the complete series of these events over the past two interglacialglacial cycles.Their duration decreases and their frequency increases during glacial build-up in both the last and penultimate glacial periods, indicating that ice sheet size affects their character and pacing. The ages of the events are exceptionally well constrained and may thus serve as benchmarks for correlating and calibrating climate records.
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