Palaeogene alluvial deposits in Liujing,Hengxian,Guangxi

There occur the carbonate cobble conglomerates and boulder conglomerates in the northeastern part of Liujing,Hengxian,Guangxi.These deposits including their lateral facies display a kind of distally separated "binary structure".The synthetic study of field reconnaissance and sampling,in combination with the examination of modern piedmont alluvial fans and ancient alluvial fans,shows that these deposits should be assigned to the residual proximal fan,mid-fan and fan fringe of a Palaeogene alluvial fan.The alluvial fan was initiated under the arid and/or semiarid climatic conditions in the early and middle stages of the Eocene,and the detritus were derived from the ancient piedmont alluvial fan from the steep carbonate rock terraces.