HEAVY MINERAL RECORD OF THE HOLOCENE ENVIRONMENT ON THE LOESS PLATEAUIN CHINA AND ITS PEDOGENETIC SIGNIFICANCE

Three sections of Holocene loess on the Loess Plateau were studied to document environmental and pedogenetic changes in heavy minerals in th e fine sand to fine silt fraction (0.25-0.01 mm). The sections were in a north-south transect and ranged in age from 10 000 +/- 200 year B.P . to the present. The heavy minerals consist mainly of homblende, epid ote and opaque minerals. However, there are differences in the content of unstable minerals and in the surface characteristics of grains, In dices based on mineral ratios and grain surface characteristics sugges t that the so-called Heilutu soil, which has been recognized as a mode rn soil, was subjected to variations in natural weathering conditions, aeolian loess deposition and human impacts. Its profile indicates tha t it is a polygenetic soil.