TEXTURE AND STRUCTURE AND PALAEOENVIRONMENT OF LOESS IN ZHAITANG BASIN OF BIJNG

The malan loess in the zhaitang basin is one late pleistocene marker stratum in China.In order to reveal the origin and palaeoenvironment of the loess in Zhaitang basin the texture and structure and grain size of the loess and its carbonate and ferromanganese aggregate in this area are studied.The result shows that the texture and structure and grain size of the loess in Zhaitang basin are similar to those of loess on the middle reach of the Huanghe River.They are of eolian deposition.But the lishi loess in Zhaitang basin is different from the loess on the middle reach of Huanghe River in that it was subject to multiple proluvial deluvial processes in its deposition process.The Malan loess were also subject to several congeliturbations,indicating that the temperature in some stages of the loess formation process in Zhaitang basin was comparatably low.