A HIGH-RESOLUTION DIATOM RECORD OF THE PALAEOCLIMATES OF EAST SIBERIA FOR THE LAST 2.5 My FROM LAKE BAIKAL |
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| Authors: | MIKHAIL A GRACHEV SVETLANA S VOROBYOVA YELENA V LIKHOSHWAY EVGENY L GOLDBERG GALINA A ZIBOROVA OLGA V LEVINA OLEG M KHLYSTOV |
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| Institution: | Limnological Institute of the Siberian Branch of Russian Academy of Sciences, 664033 Irkutsk, Russia (E-mail:root@lin.irtutsk.su) |
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| Abstract: | Two parallel drilling cores, BDP96-1 (200 m), and BDP96-2 (100 m), have been taken from top of the underwater Akademichesky Ridge in Lake Baikal and dated by paleomagnetic techniques. These cores are part of the Baikal Drilling Project (Kuzmin et al., 1997a, b). Diatom analysis of the first 100 m of these sediments reveals that they store a 2.5 Myr high-resolution continuous record of the palaeoclimates of East Siberia. Sediments belonging to warmer climates have a high content of diatom algae frustules, whereas those belonging to global glaciations are diatom-barren. The record of Upper Pleistocene (500 kyr BP) strongly correlates with the oceanic SPECMAP curve and contains distinct 100, 41, 23, and 19 kyr periods, as revealed by Fourier analysis. Diversity of diatom species was small in Pliocene. Abrupt and frequent changes of the climate in Pleistocene resulted in frequent dramatic changes in the diatom communities. The extant dominating endemics, Cyclotella minuta and Aulacoseira baicalensis, became important in Lake Baikal 760 kyr and less than 120 kyr BP, respectively. |
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