关键词: 戈壁面, 干旱气候, 环境

Abstract: Gobi is one of the primary landscapes in desert . Here, from the angle of sedimental facies or environment in gobi area, the gobi plane has been defined as the interface of the interaction between the exposed surface of gravel deposit or bedrock and the arid atmosphere. We refer to the areas overlaid by gobi plane as gobi, where the gobi plane developed over the gravel depos it is gravel gobi , and that over the bedrock is rocky gobi.There are a series of geological and geomorphological characters on the exposed surface of gravel deposits and bedrock, which have been built up under the exogenic action in arid atmosphere. Firstly, there are a lot of angular gravels on the surface of gobi plane, which were derived from mechanical weathering due to the large temperature difference there. Secondly, inasmach as the evaporation is far more than preciptation, the top-strata of gravel deposits enriched a lot of salt.The clastic grain due to salt weathering is another main origin of the angular gravel over the gobi plane.While the enrichment of salt,the physical and chemical-processes of salt resulted in the formation and development of polygons regolith, a peculiar type of microlandform. Thirdly, there are remains of the most common action in arid atmosphere,including wind erosion and wind accumulation.Deflation,that the wind blows out the finer particle (sand, silt etc.) in the clastic sediments while the gravel remains in topstrata, eventually induces the occurrence of armour of stone on the surface of gobi plane. The abrasion of blown sand forms ventifacts on the top gravel and the surface of boulder or bedrock. Whenthe wind-drift sand is blocked, there would be aeolian sand deposition. All of the underlying surface of wind agents is one of the gobi plane, Fourthly, although desert varnish was formed under a variety of setting, the most typical varnish is on the surfase of gravel and bedroce of arid gobe areas.The desert varnish grows slowly under the hyperarid climate, where a little increment of moisture would accelerate the formation of varnish.There are a lot of organic matter in humid climate, which blocks the development of desert varnish.All the geological and geomorphological characters of gobi plane would be used to determine the position of the gobi plane in the strata, and to identify how many planes of gobi is in field profile, while the gobi plane as an effective carrier of environmental information could be used to date the gravel sediments or conglomerates, and to reconstruct the palaeoclimatic change, channel swing and neotectonics.Therefore,the establishment of the new concept of gobi plane provides a new approach to study the environmental and climatic change in arid land, which would significantly prompt the research work in gobi area.

Key words: Gobi plane, Arid climate, Environment