Lacustrine sediment records provide considerable information on the environmental fluctuations in the surrounding catchments. Particularly, sediment records obtained in deltas provide precious earth surface information in the catchments of rivers forming the deltas. The long core called BDP-99 was obtained in 1999 at the margin of the Selenga Delta, Lake Baikal (in glaciated zone), which was formed by the Selenga River. The sedimentation rate is large in cold (glacial and stadial) periods while mineral grain size is comparatively large in warm (interglacial and interstadial) periods. Results suggest that erosible (transportable) materials were limited in the surface of catchments in warm periods because of large vegetation cover (humid climate) despite occasionally large discharge. A similar phenomenon is demonstrated by the core (BDP-98) from the Academician Ridge of the same lake although the sedimentation rate is much lower. By contrast, sedimentation rate and mineral grain size are both large in warm periods in non-glaciated zone (Lake Biwa, central Japan; humid temperate climate); however, only slight differences are observed between the warm and cold periods.
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