TWO LOESS PROFILES IN PINGLU,SHANXI AND CORRESPONDING PALEOCLIMATIC RECONSTRUCTION

In this paper,two loess profiles located in Pinglu,Shanxi north of Sanmenxia gorge of the Yellow River,have been studied. The magnetic susceptibility curves of Miaoxia and Yangwa profiles show that the susceptibility values of S₆ and S₁ are higher than that deposited in the corresponding period in the Loess Plateau,while the values of S₅~S₂ and L₇~L₂ are somewhat lower,being close to the susceptibility value of L₉ in the interior of the Loess Plateau. The thickness of strata of S₅~L₅ is greater than that of the Loess Plateau. A comparison with the curves of the magnetic susceptibility,δ¹⁸O in DSDP607 and V30-97,and mid-month insolation 65°N for July of Caocun profile,shows that the climatic changes indicated by both Miaoxia and Yangwa profiles are close to the interior of the Loess Plateau at the scale of 10⁵ a. This fact may reflect its consistency with the global glacial cycle resulting from the variation in solar radiation controlled by variation in some elements of earth's orbit. But there is no simple correspondence between them as shown by the greater thicknesses of deposits and relatively lower susceptibility values. It may be caused by (1) different rate of dust accumulation,(2) water erosion,(3) different source materials and (4) variation in local soil forming conditions.