Preliminary Study On The Theory And Modeling Of Planation Surface

This paper probed the theory and modeling on the planation surface through its definition, discrimination, classification, distribution, formation , dating, and so on. We also made 3D presentation and analysis of the planation surface by using Photoshop, MapGIS and Excel.Planation is a combination of external agents. Erosion is the primary significance in that it cuts all the strata formed previously and in the combination with transportation and accumulation, directly affects the formation of planation surface. There are lowering and backing of the ground when it was planated. Planation can be classified into many types such as peneplaination, pedimentation, cryoplanation and double leveling surfaces planation.Planation surface is a wide-ranging and undulating surface formed by planation in a long and relative stable period or in a decreacing-development period . It is near the base level and there always exists some deposits such as crust of weathering above it. Planation surface is often uplifted or buried by the later tectonic activities.Original planation surface has some features, for example, it appears in large area with low altitude, small gradient and taking a long formation period, etc.Discrimination of planation surface is based on plotting and field investigation and by using statistical methods and "3S" technique. It enhances the accurate, objective and quantitative analysis of planation surface.We can classify planation surface by many standards. According to whether there are later tectonic activities or not it can be divided into mountain planation surface, lower planation surface and buried planation surface. According to active condition, it can be divided into active surface, dormant surface, exotic surface and defunct surface. Taking the base level into consideration, it can be divided into sea-eroded and deposited planation surface, denudated planation surface, snowline planation surface and upper eroded planation surface. According to geologic basement, it can be divided into stable-floor planation surface and active-floor planation surface. According to climate zone, it can be divided into pediment and pediplain, double leveling surfaces and etchplain, peneplain and cryoplain.We strengthen the investigation of natural factors such as pre-construction, erosion base level, climate, lithology, time and tectonic activities, which affect formation and preservation of planation surface. Pre-constrction affects the time and degree of the planation. Erosion base level is the base line for it. Cliamte affects the planation directly and indirectly. Lithology impacts the procedure and time. Later tectonic activities make against the preservation of it. Different type of planation surface has different formation, the difference of planation results in the difference of planation surface.Chronology of planation surface is one of the most important part of the study. The age of planation surface means the end of the planation. Phase-transition analysis, age-boundary line analysis, correlation and crust of weathering analysis are all used in determining the age of the planation surface.We also considered the 3D presentation and analysis of the planation surface.