摘要
大规模沙漠化从岩石记录中可以追溯到中生代中期,第四纪以来南北两半球各存在一条中纬度沙漠带,中国的沙漠化是这个全球沙漠化进程的一个组成部分。沙漠化是在地质演化过程中受内、外动力地质作用联合控制的地质事件,是岩石圈与大气圈、生物圈及水圈强烈作用在地壳表层形成的一种特殊地质现象。这种现象的形成与演化是漫长的和具有周期性的,不会因为局部的条件变化而发生整体意义上的突变。人类活动是局部的,在整个地球沙漠化进程中只是起到一个加速剂的作用。沙漠化过程可分为3个阶段,即物理风化与沙源积聚阶段、风沙作用阶段和沙漠化阶段。沙漠期后沙丘沙经过固化生草、胶结成岩阶段后即形成风成砂岩。
Rock records indicate that largescale sand desertification dates back to middle Mesozoic Era, that there has existed a middle latitude sand desert zone in the south and north hemispheres respectively since Quaternary Period, and that sand desertification in China is a part of global sand desertification process. Sand desertification, controlled by internal and external dynamic geological processes in the geological evolution, is a special geological phenomenon imposed by the interaction of lithophere, atmosphere, biosphere, and hydrosphere on the surface layer of the earth's crust. The evolution of sand desertification, which is long and periodic, won't undergo a sudden change in a whole sense because of partial condition change. Human activity is regionally restricted, serving as an accelerator in the global sand desertification. The process of sand desertification can be divided into 3 stages: physical weathering and accumulation of sand source stage; windblown and sandblast stage; sand desertification stage. The windformed sandstone was formed by the dune after solidifygrassing and cementationdiagenesis stages.
出处
《资源调查与环境》
2003年第3期157-166,共10页
Resources Survey & Environment
关键词
沙漠化
沙丘岩
动力地质作用
演化模式
sand desertification
dune rock
dynamic geological process
evolution model
