VARIABILITY OF HOLOCENE CLIMATIC EVENTS RECORDED IN PEAT SEDIMENTS FROM THE TIBETAN PLATEAU

North Atlantic deep sea sediment records indicate that the Holocene climate has been punctuated by abrupt shifts with a cyclicity close to 1500 yr, forming part of a millennial scale climate cycle operating independently of the glacial-interglacial cycle¹. Recent examination of a peat bog profile along the Tibetan Plateau has involved high resolution sampling (15-30 yr) and sensitive proxies together with reliable 14C AMS dating. Among other sharp fluctuations, we have recognized a series of cold, dry Holocene events and correlated well with ice rafting events recorded in North Atlantic Ocean sediment cores¹ and sedimentary sequences from the Arabian Sea. Spectral analysis of our data indicates high frequency climate variation with a predominant cyclicity of 1460 yr. This high-to mid-to low latitude relationship can only occur through an ocean-atmosphere coupling mechanism^2,3. Hence the role of the Tibetan Plateau as a conduit for both high and low latitude climate variations needs to be examined more closely.

References:

1.Bond, G., Showers, W., Cheseby, M., et al., A pervasive millennial-scale cycle in North Atlantic Holocene and glacial climates. Science, 280, 1257-1265 (1997).

2.Zhou, W. J., Head, M. J., Lu, X. F., et al., Teleconnection of climatic events between east Asia and polar, high latitude areas during the last deglaciation. Palaeogeog. Palaeoclim. Palaeoecol., 152, 163-172 (1999).

3.Zhou, W. J. et al. Terrestrial evidence for a spatial structure of tropical-polar interconnections during the Younger Dryas Episode. Earth and Planetary Science Letters 191, 231-239 (2001).