Study On The Age And Period Of Soil And Forest Landforms In Yuanming Soil And Soil

Yuanmou Basin has developed the most famous earth forest in southwest China.The awareness of the landscape’s formation age is an important foundation of depthdevelopment for regional tourism resources and erosion control. Previous studiessuggest that the bottom of Yuanmou Formation (the first two segments of YuanmouFormation) which age is the late Pliocene-early Pleistocene composed the earth forestformation. Stratigraphic correlation and age analysis in this thesis suggest that thesubject of earth forest formation is multiple sets of fluvial gravels developed at aboveof Yuanmou Formation, instead Yuanmou Formation. The whole formation isdescribed as follows:(1) There are brownish red silt and grayish white clay in the first set stratum. It istilted to the northeast and the stratigraphic’s ESR age is1.21Ma. This YuanmouFormation widely distributed through the whole Yuanmou Basin.(2) The second set formation is brownish red sandy soil, strata level, and thestratigraphic’s ESR age is0.84Ma. This set of stratigraphic is distributed smallersquare, mainly in Aichang.(3) The third set formation is sand gravel, strata level, the stratigraphic’s ESR age is0.74～0.54Ma. This set of stratigraphic is distributed in Yidi, Banguo, Aichang, thesquare is wider.(4) The forth set formation is sand gravel, strata level, the stratigraphic’s ESR age is0.3Ma. This set of stratigraphic is mainly distributed in two sides of Qingling Riverand Wanbao.(5) The fith set formation is brownish yellow and grayish white sandy soil, strata level.The stratigraphic’s ESR age is0.21Ma. This set of stratigraphic is distributed inHuaxin and Langbapu of the southwest basin which elevation is1600m.According to various strata of sedimentary characteristics, contact relationship andformation history, we have restored the formation history of Yuanmou Eearth Forestlandscape, divided it into the following phases:(1) After Yuanmou ancient lake deposition, it began to deposit a0.8Ma forest soil strata and developed the first stage soil forest landscape during1.2～0.8Ma.(2) It began to deposit a0.7～0.5Ma forest soil strata after the end of0.8Ma forestsoil landscape sediments, and during0.7～0.5Ma, it developed the second stage siolforest landscape.(3) After the end of the0.5Ma earth forest strata, the0.3Ma earth forest strata startedto deposit. During0.5～0.3Ma, it developed the third stage siol forest landscape.(4) After the end of the0.3Ma earth forest strata, the0.2~0.1Ma earth forest stratastarted to deposit. And developed the forth stage siol forest landscape.(5) It developed the fifth stage soil forest landscape after the0.2～0.1Ma earth forestsediment which age is also from0.1Ma to now.