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由于新构造运动作用,宁夏沙坡头地区从早更新世以来发育了多达9级的黄河阶地。在高阶地上部发育非水相结构的黄色粉砂-砂沉积物。光释光测年结果最老为74ka,大部分年龄处于末次冰期的早期。这与黄河阶地的形成时代不一致,推断这些沙沉积物并不是与阶地同时形成的,而是末次冰期干冷环境下的风成物质。这些风成沙沉降到阶地面后,进入以砾石为主的黄河阶地堆积物而保存下来,可能指示了腾格里沙漠东南缘沙漠在末次冰期干冷气候背景下的扩张。本研究提供了在末次冰期气候干冷背景下腾格里沙漠扩张和风沙活动增强的直接证据。
Due to the neotectonic movement, up to 9 levels of Yellow River terrace have been developed in Shapotou area of Ningxia since Early Pleistocene. Yellow silt-sand sediments of non-aqueous facies develop in the upper part of the upper. Photoluminescence dating the oldest 74ka, most of the age in the early Ice Age. This is inconsistent with the formation of the Yellow River terraces. It is concluded that these sediments are not formed at the same time as the terraces, but rather as the wind-forming substances in the dry and cold environment of the last ice age. The deposition of these aeolian sediments into the graded sediments of the Yellow River after settling on the terrace surface may indicate the expansion of the desert in the southeastern margin of the Tengger Desert against a dry climate in the last glacial period. This study provides direct evidence that the Tengger Desert expansion and sand blown sand activities were enhanced in the dry and cold climate of the last glacial climate.