Loess Magnetic Susceptibility in Central Asia and its Paleoclimatic Significance

For standard loess sections in the Chinese Loess Plateau (CLP), paleosols always have higher magnetic susceptibility (MS) than adjacent loesses. But this characteristic is not always suitable to MS records in loess-paleosol sequences from Central Asia. Here we report MS results of two loess sections in Yili basin, Central Asia. The MS variation of one loess section with an elevation of 1432m is identical with that of loess-paleosol sequences in the CLP, but the other one at 875m have opposite trend. Based on field investigation, pedogenesis characteristics observations, carbonate, lithological and grain-size correlations, the authors suggest that the differences of regional paeloprecipitation related to altitudes during last interglacial period between the two sections are responsible for their differences of MS. Carbonate deposits also have influence on decrease MS. The susceptibility enhancement of pedogenesis model for loess-paleosol sequences in the CLP can not interpret completely the MS variations of loess sections from Central Asia area. It should be careful to reconstruct paleoclimatic change using susceptibility as a proxy in Central Asia area.