Grain-size distribution in the lake deposits from the Buridun Lake in Inner Mongolia as an indicator of aeolian activity

The present paper is concerned with some aspects of the lake deposits in the Buridun Lake in Inner Mongolia. The aims are, firstly, to construct the grain-size sequences for the Buridun Lake during the last 50 years on the basis of grain-size composition, carbon and oxygen isotopes and ²¹⁰Pb/¹³⁷Cs age determinations, and secondly, to clarify the trend of the aeolian activities on the basis of the comparison of annual average sandstorm days (data from 100 meteorological observatories) in the study area and northern China. The coincidence of the variable trends of the fine grains (4 to 16μm) contents in the Buridun Lake deposits and sandstorm days in the Ongniud Banner may indicate the states of regional aeolian activities. The greater differences of variable trends of the coarse grains (> 64μm) contents in the Buridun Lake deposits and sandstorm days in the Ongniud Banner indicate that the lake area may be affected by the land desertification caused by lagre-scale human activities rather than the aeolian activities. Therefore, it is inadvisable to develop the lagre-scale human activities in the Ongniud Banner region. This will be very important to the protection of ecological environments and regional wind protection and sand fixation.