“演变阶段”与“成因”不能混为一谈──也谈白洋淀的成因

Formation or Development Stage-A Discussion on the Cause of the Formation of Baiyangdian Lake, China

白洋淀湖盆是河流差别堆积形成，属于扇间和河间洼地湖盆．它有着发生、发展、缩小、消亡的自然演变过程．人类活动也使其有过扩大、缩小，甚至干涸的过程．但这仅是其中的一个演变阶段，而不是其成因。

There exist several ideas upon the cause of formation of Baiyangdian Lake, North China Plain. Recently, Zhu Xuanqing. et al (1994) pointed out that Baiyangdian Lake used to be an outcome of human activities in the book titled 'Environmental Evolution and Prediction of Baiyangdian Lake ' (Xi'an Atlas Press, 1994. ). That conclusion drawn by Zhu, et al (1994)was based on the follows: 1) The geographical environment during the Middle Holocene in the plain was not suitable for lake formation ; 2) The existence of Lumprotula spp. fossils in the sediment revealed a corresponding fluvial sedimentary conditiont 3) The historical remains of Neolithic Age and Zhangguo Dynasty demonstrated that there was not a vast and unified lake at that time. The authors here present a new look on the above views. It was the differential accumulations of various rivers that formed Baiyangding Lake, a lake between alluvial fans and rivers. The lake has its own emergence, development as well as dry-up processes during its evolution history. Human activities could trigger the outcome of expansion, reduction and even dryup in history. whereas each was merely one of the different stages in the evolution history of Balyangdian Lake, instead of the cause of formation instead.