Paleo Karst Landforms In Neogene Period In Dalian Area And Developing Features Of Its Overlying Red Weathering Crust

Karst landforms are distributed widely all over the world and they are mainly distributed in East China and Southwest of China as they have features of widely distributed and varies of forms.Step of Karst landforms researching in China was started relative dragged but complete and systematic theory was established after penetreation and intercross of different subjects like geology,geomorphology,environics and pedology.Heavy red weathering crust customaily developed overlying the Karst plantation surface was mainly being researched in south area of China but relative research in north area of China was less concerned with less systems established.Karst landforms are developed widely and typically,which is seldom seen in north area of China so that research of Karst landforms in Dalian region and its overlying red weathering crust has remarkble academic meaning and innovative significance.As obervasion of Karst landforms developed in Chengshantou in Dalian area is regarded as a breakthough point,this paper discusses the distribution and developing mechanism of paleo Karst landforms in Dalian by description of landforms and geological research in Dalian region.To analysis climatic features during the paleo Karst landforms' developing period,14 samples of Shicao village in Dalian was sized(13 samples sized from the profile and 1 from underlying bedrock).Based on particle size analysis and geochemical feature analysis on developing feature and process of profiles' revolution in north region of China,some points can be concluded as follows:Firstly,paleo Karst landforms developed in Dalian region is mainly performed as karren,clint and stone forest,some uvalas and dolines can be seen in some places.This place is during the early period of Karst landforms developing from developing condition,mechanism and process.Secondly,average index of sand grains in red weathering crust of Sicao profiles is 28.46%,average value of silt content is 58.28%,cosmid is 13.26%.Particle size distribution of this profile is performs as more silt sands with secondary sand grains and less cosmid,which indicates that feature of particle distribution of red weathering crust developed in limestone as bedrocks in north China is relative coarse,degree of weathering crust is low in weathering developing period.Thirdly,average value of powder viscosity ratio is 4.83%and it is relative higher in whole profile.From this point it can conclude that degree of weathering effect of red weathering crust in Shicao profile is relatively low.Fourthly,content of Si is relatively large with exception of S4 overpass 50%,contents of Fe,A1 is relatively lower,content of some alkali metal elements tends to leaching like Na,K and Ca is low.Average value of CIA is 46 indicates that climate feature corresponded with this profile is a kind of warm and humid climate.Average value of silica-sesquioxide ratio is 3.33 indicates that effect of Si leaching and Fe accumulation is strong.Fifthly,According to trendency of CIA,silica-sesquioxide ratio and salt leaching index with depth changing combined with content changing trendency of cosmid,silt and grain with depth changing in Shicao profile,degree of weathering crust developing waved strongly during period of Shicao profile developing.It appears two periods of weak developing stage in depth of 150cm and 250cm,which means it is not suitable for weathering crust developing in this kind of hydrothernal condition;Three relatively better periods are detected in layer of over 100cm over,125cm and 300cm,which means it is suitable for weathering crust developing in this kind of hydrothemal conditon.