摘要
东北平原是中国最大的平原，也是全国著名的粮仓。半个世纪以来，荒漠化发展的速度很快，严重影响社会经济的可持续发展。构造一气候旋回，冰期一间冰期气候的波动对第四纪环境的演化起了关键作用，干冷气候可导致沙漠化的发展，湿润气候促使土壤和植被发育，对沙漠化起到了抑制作用。自晚更新世以来，在干、湿气候交替出现的过程中，土壤的苏打化过程和脱苏打化过程也在交替进行。东北平原的沙质荒漠和盐碱荒漠主要是因为人们对土被、植被的破坏所造成的。东北平原是对世纪重要的经济开发区，研究治理该区的荒漠化有重要的战略意义。
ortheast plain is the biggest plain in China. During the half past century, theareas's soil desertification expanded rapidly at a velocity of 1.4% / a, which deeplyaffected sustainable development of the society and economic.Cycle of structure and climate, and fluctuation of glacial and inter glacial epochtake a key role in the Quaternary environmental evolution. During the Pre-Pleistocene,climate turn from dry and cold to humid. At this time, the earth's crust subsideddelicately, received the deposit of clastic rocks of river face around the basin andformed large scale lake in the center of the basin. At the fare Period ofPre-Pleistocene, the earth crust raised. In early Period of the Middle Pleistocene, theclimate alternated with humid and dry-cold. At later of this time, climate turned intohumid and deposited from river factes to lake factes. The lake basin area was thebiggest and was 5000km2. The deposits of sand and loess were formed in thesouthwest of plain. In the Late Pleistocene, climate became into warm from cool andhumid, and then turn into dry and cold, which resulted in the windy sand flow anddust storm, and sandy desertification expand again. Windy sand flow extend to theeast of plain. It is the prime period of the desert development.Since the Holocene, deserification has had four times development and reversion,and formed four layers ancient soil due to many times of advance and retreat of theeast Asia monsoon, and climate zone migration between north and south. At that time,the ancient soil and swamp developed and the flowing sand were fixed.The sand area in Songnen plain is 1.122× 106hm2, taking up 10.50% of the totalare4 while the potential deserted soil takes up 56%, being deserted soil takes up 36%,strong developing deserted takes up 7% and heavy developing deserted soil is 1%. Itis obvious that the threat of the potential desertification is serious, the alkalinized soilzone of northeast Plain is one of the three world alkalinized soil zones and mainlydistribute in the low and internal part.Geological and geo-chemical environment and arid climate are helpful for thesoda transportation and eoncentration in northeast plain. Alkalinization started in theLate Pleistocene. For a long time, alkalinization alternares with arid and hnmid climate,and the process of alkaline salination and desalination was made in soil. The soilcovering and vegetation take an important role in depressing alkalinization. Naturalalkalinization often goes through hundreds or thousands years. Under the action ofhuman, salinized desert can be formed within 10~20 years.The desertification in northeast plain is composed of sandy desertification andsaline-alkali desertification, which are closely related with the evolution of Quaternaryenvironment and human activities. We should build information system for evaluation,monitor and precaution to supply scientific basis for studying and protecting thedesertification.
出处
《第四纪研究》
CAS
CSCD
北大核心
1999年第5期448-455,共8页
Quaternary Sciences
基金
国家自然科学基金
关键词
第四纪
生态环境
荒漠化
东北平原
古环境
Quaternary, ecological environment,desertification, northeast plain
