Holocene Stratum And Sediment Environmental Memoir Of Mu Us Desert

Holocene stratum and sediment environmental memoir of Mu Us desertBased on a great quantity of detailed reviews in field .. sample's analyses and tests in laboratory, this thesis makes a detailed research on Holocene deposits characteristics of Mu Us desert, especially on characteristics of grain size composition, which break through previous description of determining the nature and gain a series of number indexes. At the same time, thisthesis has also researched arenaceous source on every part of Mu Us.Firstly Mu Us desert's forming process is deeply influenced by the East Asian monsoon, the grain size gradually becomes smaller, while the magnetic susceptibility becomes larger from northwest to southeast This phenomenon not only appears on the surface of Mu Us, but alsoobviously reflects on the same layer of different places. Setenaly According to the analyses from selected profiles, we know that, it is cold and dry in thisregion during the early Holocene when East Asian winter monsoon's influence is obvious, so, it is a transition period from sand deposit to sandy soil deposit, when the layers become thinner gradually from north to south. During Middle Holocene, it is warm and humid, influenced evidently by East Asian summer monsoon, so, it is an obivious pedogenesis, when there are generally well-developped Holecene palaeosol(So) from north to south, and the pedogenesis in the south is better than that in the North, the soil is also thicker than that of the North. From late Holocene to now, the climate changes to be dry and cold, but its changing scope is smaller than that of last glacial period.therdly Because of the influence of terrain and geological structure, arenaceous resources of different regions are different in Mu Us. sands are mainly from riverway in northwest; from efflorescent cretaceous sandstone on account of higher topography in the middle part of Mu Us; and sands resources are intricated in southeast, mainly including riverway sands, sands blown by the wind and embedded sands under So. Complicated sands resource is also a reason of serious sandy phenomenon.