VARIATION IN LOSS ON IGNITION OF THE NILKA LOESS SECTION IN THE YILI BASIN AND ITS IMPACT FACTORS

513 loess samples from the Nilka section in the Yili basin, Xinjiang, have been analyzed for Loss on Ignition (LOI) at 550℃and 950℃respectively. Correlation analysis has been carried out among the organic matter, fine components <4 μm, carbonate and high-temperature LOI. X-ray diffraction has been used to identify the mineral composition after representative samples were burned. The results show that the clay fractions (<4 μm) of the Nilka loess have some correlation to the LOI variations at 550℃, which reflects the changes in soil organic matter and bound water. And the LOI at 950℃ can reflect the content of soil carbonate. In other words, the contents of carbonate of the Nilka loess is positively related to the LOI at 950℃. Thus we can infer that the high value of LOI at 950℃ represent a cold and dry climate while the low value reflects a warm and wet climate. These conclusions have a profound significance for understanding the paleoclimatic conditions of the loess-paleosol development in Yili region. This also suggests that the LOI is a simple and fast method for paleoclimatic studies of loess sediments in the westerly-dominated Yili region.