A high-resolution, absolute-dated Holocene and deglacial Asian monsoon record from Dongge Cave, China

We present a continuous record of the Asian monsoon over the last 16 ka from delta O-18 measurements of stalagmite calcite. Over 900 oxygen isotopic measurements providing information on shifts in monsoon precipitation are combined with a chronology from 45 precise Th-230 dates. delta O-18 and therefore Asian monsoon intensity generally follows changes in insolation, although changes in delta O-18 are generally accommodated in abrupt shifts in contrast to smoothly varying insolation, indicating that threshold effects may be important. delta O-18 decreased dramatically (similar to 3 parts per thousand) at the start of the Holocene (similar to 11.5 ka) and remained low for similar to 6 ka. Four positive delta O-18 events centered at 11225 +/- 97 yr BP (1.05%o), 10980 +/- 117 yr BP (1.15 parts per thousand), 9165 +/- 75 yr BP (1.4 parts per thousand), and a double event centered at 8260 +/- 64 yr BP (1.1 parts per thousand) and 8080 +/- 74 yr BP (1.0 parts per thousand) punctuated this period of high monsoon intensity. All four events correlate within error with climate changes in Greenland ice cores. Thus, the relationship between the Asian monsoon and the North Atlantic observed during the glacial period appears to continue into the early Holocene. In addition, three of the four events correlate within error with outburst events from Lake Agassiz. The decline of monsoon intensity in the mid-late Holocene is characterized by an abrupt positive shift in delta O-18 which occurs at 35505 +/- 9 yr BP (1.1 parts per thousand in similar to 100 yr). In addition, the Holocene is punctuated by numerous centennial- and multi-decadal-scale events (amplitudes 0.5 to 1 parts per thousand) up to half the amplitude of the glacial interstadial events seen in the last glacial period. Thus, Holocene centennial- and multi-decadal-scale monsoon variability is significant, although not as large as glacial millennial-scale variability. The monsoon shows a strong connection with northern South American hydrological changes related by changes in ITCZ position. Spectral analysis of the delta O-18 record shows significant peaks at solar periodicities of 208 yr and 86 yr suggesting variation is influenced by solar forcing. However, there are numerous other significant peaks including peaks at El Ni (n) over capo frequencies (observed for high-resolution portions of the record between 8110 and 8250 yr) which suggest that changes in oceanic and atmospheric circulation patterns in addition to those forced by solar changes are important in controlling Holocene monsoon climate. In addition, for this high-resolution portion, we observe a distinctive biennial oscillation of the Asian monsoon, which has been associated with the Tropospheric Biennial Oscillation (TBO). (c) 2005 Elsevier B.V. All rights reserved.