Palaeoclimate
Lake Baikal contains a potentially uninterrupted palaeoclimate record extending back over 20 million years. This record is of significant importance, given the lake’s position in one of the world’s most continental regions where there are few continuous, high quality records spanning the Quaternary (last c. 2.75 million years).
In the latest issue of Earth-Science Reviews [http://dx.doi.org/10.1016/j.earscirev.2007.03.002] I have written a review which provides a synthesis of Lake Baikal paleoclimate studies that exploit the sedimentary diatom record and associated diatom / biogenic silica (BioSi). I focus on diatoms and biogenic silica because they are the most extensively utilized paleoclimatic proxies found in Lake Baikal sediments, and arguably the most important. (Although other biological proxies are increasingly being utilised to great effect, including pollen, pigments, alkenones, TEX86, etc). I will provide information on each of these in future posts.
In Mackay 2007 I outline (1) the major hydrological and climatic features of the Lake Baikal region; (2) discuss the properties of diatoms in Lake Baikal, relevant to their use as paleoclimatic proxies; (3) provides a synthesis of studies that have utilized either diatoms or aspects of diatom silica to reconstruct central Asian paleoclimate at various timescales throughout the Quaternary (here taken as beginning c. 2.75 Ma). For each timescale, I initially outline current issues, followed by a critical examination of how the Lake Baikal records have added to the scientific body of knowledge. Central to these findings are the causes of climate change over the Quaternary, and there have been several accounts published recently on possible climate forcing mechanisms throughout this epoch.
In the synthesis I therefore took the opportunity to provide an assessment of potential forcing mechanisms in central Asia during each of the relevant timeframes, which are likely to be contributing to change in the region of Lake Baikal (i.e. glacial-interglacial cycles; interglacial climate variability; abrupt climate events associated with Heinrich Events and interstadials; abrupt climate events associated with Dansgaard-Oeschger cycles and Termination 1; Holocene climate variability; climate change over the last 1000 years).