花海湖泊全新世古风成砂的发现及其古环境解释

通过野外调查和室内分析,发现在花海剖面全新世出现了三次风成沙沉积,并对其原因进行了初步分析。初步认为风成沙的细粒组分可能主要为近源湖相,而粗粒组分则为沙漠戈壁区吹来。前两次风成沙在形成时代上可能与第一新冰期相对应,反映了沙漠的扩张状态。而且分析表明第一风沙形成期的冬季风强度和沙漠化过程似要比第二风沙期强,持续时间长。本区在全新世人类大规模活动之前就曾存在两次明显的沙漠化扩张过程,这为研究区域土地退化、荒漠化等问题提供了自然背景,特别是对西部大开发战略重点之一的生态环境保护与建设具有特殊的意义。

Discovery of Holocene Aeolian Sand in Huahai Lake and Its Environmental Significance

On the basis of field investigation and laboratory analysis, it was found that there were three layers of aeolian sand in Huahai Section, a Holocene lacustrine sediments. It was primarily assumed that the fine group in aeolian sand was the deposition of nearly lacustrine composition, while the thick was from desert. The time of the earlier two layers of aeolian sand formed corresponds with the New Ice Age. More-over, it indicates that intensity of winter monsoon in the first period of aeolian sand formed was stronger than that in the other twos in Holocene, and the duration is also longer. These provide natural background of the soil regeneration, desertification and has significant implication to the preservation and construction of ecological environments in West China.