TY JOUR TI Evolution and variability of the pleistocene ice ages: A~new view KW Paleoclimate KW orbital theory KW ice ages KW Middle Pleistocene transition KW insolation KW marine isotope stages JO Russian Journal of Earth Sciences AU Bol'shakov, V.A. AU Kuzmin, Y.V. PY 2014 IS 14 PB Geophysical Center of the Russian Academy of Sciences