FORMATION ENVIRONMENT OF NET VEINED LATERITE AND XIASHU LOESS AND THEIR AGES IN THE AREA ALONG THE YANGTZE RIVER, ANHUI PROVINCE
Yu Zhengjiang; Huang Duocheng(Anhui Institute of Environmental Gedlogy,Bengbu,233000)
Many geologists such as Li Siguang (J .S.Lee)(1934),Xu Jie(1936),Yang Huairen(1958),FangHongqi(1961),Xu Xing(1984)and Yang Dayuan(1991),Studied net veined laterite and Xiashu loess They generally regarded the former one as glacial deposits in the Middle Pleistocene and the latter as eolian and overflowed deposits in the -rock flow deposit.Through comprehensive study of lithological features,stratigraphic squence,paleomagnetic and thermolumiescent dating as well as geochemical features,the authors got new ideas as follows.(1)The net veined laterite formed in the area of mountainous, hilly peleogeographic landscape with environment ly of proluviai-fluvial,eluvial-deluvial,deluvial-proluvialand mud-rock flow accumulation,in age 0. 45-2. 5 MaB.P.with the lower boundary corresponding to that of Wucheng loess in the northern China.(2)The Xiashu loess formed in the peleogeographic landscape area of piedmont hummucky inclined plain of drysemiarid,temperate-warm temperate climatic environment.They are mainly eolian,and proluvial-fluvia,eluvialdeluviat as well secondarily,in age 0.13-0.45Ma B.P..corresponding to the upper Lishi loess in the northern China.