" style="margin: 0cm 0cm 0pt;">The
different grain size content range from 0.5~500 μm and magnetic susceptibility
were measured to study the correlation between grain size and magnetic
susceptibility, selected more 590
samples, in sediments from Core
Changping. The results show that magnetic susceptibility of the profile is of
some relationship with that of the content of different grain sizes, the correlation coefficient between
susceptibility and the mean grain size is positive for the whole core. The
magnetic minerals are mainly concentrated in fractions with coaster grains.
Furthermore, the correlation between
grain size and magnetic susceptibility is also affected by sediment source, the degree of sorting process and so on. The
correlation coefficient of susceptibility with the content of 0.5~30 μm, especially 0.5~10 μm, is negative, and with the content of 65~500 μm is positive,
dominated by large particles of magnetic
minerals in the core. In addition, the
correlation is different in various depth. Due to the different condition of lake
and aggregation, the correlation between
magnetic susceptibility and grain sizes should be analyzed depending on
deferent sedimental environment. When the strong hydrodynamic, magnetic susceptibility are relatively large, and relatively weak, the magnetic susceptibility is relatively
small. Therefore, the grain size and
magnetic susceptibility changes to reflect the changes in hydrodynamic
conditions, indicating that changes in
the strength of the East Asian monsoon. Especially, the climate cycle from the Quaternary period, the to-and-fro of the glaciation and
interglaciation, we concluded that
data and magnetic susceptibility, particle size and get paleoclimate information
of the drilling: 1100~800 ka B.P. is mainly cool and there is a small heating between
them, 800~600 ka B.P. cool and warm
alternate in temperature, 600~400 ka
B.P. climate is prior to hot and humid, 400~200 ka B.P. climate is prior to cold and
dry, 200~0 ka B.P. climate is priority
to cool alternate fluctuation. Research shows that the core may reflect the
8~10 climatic cyclicities. The area of precipitation increases in humid climate
period, with alluvial deposits
containing more coarse particles and larger magnetic susceptibility. The
fluctuations of susceptibility indicate the changes of paleoclimate.