Siberian paleoclimate records: insight into millennial climate cyclicity during Holocene and the Last Glacial Maximum | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Siberian paleoclimate records: insight into millennial climate cyclicity during Holocene and the Last Glacial Maximum

Friday 20 May 2016
Séminaires communs Géomagnétisme-Paléomagnétisme
Vadim A. Kravchinsky
(Dept. of Physics, Univ of Alberta (Canada))
Extrait: 

A high-resolution study of the continuous (1) Holocene loess–soil sequence and (2) Last Glacial Maximum (LGM) piston core sediments from Lake Kotokel was conducted near Lake Baikal in Siberia, far from marine environment influences. This was accomplished in order to assess the difference between North Atlantic marine and Asian in-land climate variations. Relative wind strength was determined by grain size analyses of different stratigraphic units. Petromagnetic measurements were performed to provide a proxy for the relative extent of pedogenesis in Holocene. Pollen analysis for the lacustrine sediments with an average temporal resolution of 40 years was performed to evaluate the regional environmental dynamics in the study region during the LGM.

Spectral analysis of our results demonstrates the periodic changes of 1000 and 1500 years in relatively warm and cold intervals during Holocene and the 1000 year cycle during the LGM. The 1000 year climate cycle is interpreted to be driven by the solar insolation variations reaching the Earth surface and amplified by other still controversial mechanisms. The 1500 year cycle associated with the North Atlantic Bond events appeared only in late Holocene and probably was not a common characteristic for the continental environment during early Holocene and the LGM.