Home – Home – Jornals – Russian Geology and Geophysics 2013 number 1

We present results of study of Holocene and Late Pleistocene deposits recovered on the underwater Akademicheskii Ridge in Lake Baikal. The change in mineral composition and grain size in the bottom sediment core is closely consistent with the change of major diatom complexes marking the Holocene–Late Pleistocene boundary. A high content of chloritoid (up to 14.6 %) has been found among the heavy minerals of the sand fraction of Late Pleistocene clays. The concentration of chloritoid in Holocene mud is no higher than 1.2 %. The source of chloritoid is chloritoid shales of the Anaya Formation (Upper Proterozoic), widespread in the watershed of the Primorskii Ridge in the upper reaches of the Lena and Anaya Rivers. Chloritoid was transported to the area of the Akademicheskii Ridge by predominant western and northwestern winds, which is also evidenced from the absence of mechanical impacts on the surface of its grains. The high contents of chloritoid in the Late Pleistocene sediments are due to the more intense eolian transportation at that time as compared with the Holocene.