冰缘风沙地貌与沉积研究进展

冰缘风沙地貌与沉积是在冰缘寒冷干旱气候环境中,伴有冰川或冻融作用影响,主要由风沙作用形成的荒漠地貌.现代冰缘荒漠主要分布于南、北半球的高纬度地区及中低纬度的高海拔地区,部分温带沙漠也有古冰缘荒漠沉积分布.冰缘沙丘的规模一般较小,沙丘沉积富含腐殖质及冰粒,并兼具冻融和积雪层理构造等,砂的化学及物理成熟度较低.冰缘风沙沉积往往与邻近的其它沉积相伴生,如黄土、冰川、湖泊、海洋甚至火山碎屑,因而可参与区域气候、环境,尤其是古环流的恢复与重建,也可为研究温带荒漠在冰期时的演化提供参考.目前在冰缘沙漠研究中已经取得了一些可喜的成绩,但在确定冰缘荒漠的原因过程方面还没有形成系统的理论,更多工作有待进行.青藏高原腹地的普若岗日冰缘沙丘与戈壁,是我国典型的冰缘荒漠地貌与沉积,研究其地貌与环境过程,对丰富我国沙漠学研究内容和了解晚第四纪高原腹地气候、环境变化具有重要意义.

The Periglacial Blow-Sand Landform and Sediment: a Review

The periglacial Aeolian landform and deposition is the desert physiognomy formed by the blown sand under cold and arid environment,always accompanied with the impact of glaciers and freezing and thawing.Most modern periglacial deserts are distributed mainly in the high latitude or middle and low latitude regions with high altitude.Whereas,some ancient periglacial sandy deserts depositions are distributed in modern temperate deserts.Usually the scales of periglacial dunes are smaller.The periglacial dune deposits are with abundant organism,ice flakes,freeze-thawing structure and firn stratum.Also,the sand has low chemical and physical maturity.The periglacial aeolian sediment coexists with some other facieses such as loess deposition,glacier deposition,lake deposition,deep sea deposition and volcanic clastic depositions etc.Therefore,they can be used to reconstruct local ancient climate and environments.Also they provide references to research the evolution of modern temperate desert during the Glaciation period.Recently,much achievement has been acquired in this field.However,it is hard to make certain the causes and processes of the paleo-periglacial and periglacial deserts due to the immature theory,more work should be carried out.The Pruogangri periglacial sandy desert and gobi,located in the hinterland of the Tibetan Plateau,is the typical one in China.Studies on these landforms and environmental processes can enrich the contents of sandy deserts and play an important role in understanding the local climate and environment changes since the Late Quaternary.