The survey of colloids and silts on spreadig flood station in Kabudar -Ahang EARA BY rare Earth element

Category Sedimentology
Group GSI.IR
Location 20th symposium on geosciences
Holding Date 16 April 2008

     Base on appearing numerous problems in spreading flood stations, caused by fine grains sediments after flood sedimentary, like decreasing the permeability and hardening of the soil and also, producing 1 5000 ton sedimentary clay and silte during two floods in spreading flood station of kahudar ahang and decreasing the permeability rate about 0.35 cm/h (Yaghubi,2000), this survey aims to determine the provenance of these sediments, in order to control
them. For this reason, after producing the map of drianage net and watershed, there obtained about 60 samples from fine sediments main drianage, spreading flood area, sedimentation bassin and soils. Also, 18 lithic samples were obtained from different lithologies, of which 8 samples analyzed by the method of x-ray differactometery (X.R.D). Another 18 samples analyzed by the method of neutron activation analysis to calculate R.E.E rate, “tb” and “Sc” elements. There is also 9 samples analyzed by the method of producing thin section. at first, geological map was drawn, by the help of results, second R.EE rates were normalized based on cI-chondrites and post Archaen Australian Average shale (P.A.A.S), as the base values. Then scatter and pattern diagrams and their aboundance were drawn after calculating different factors like La/Sm,..., Eu/Eu* in addition aboundance diagrams of “th”, “Sc” and “Lalth” , “tb/sc” rates were also drawn and studied. results were:pattem diagram of Naser Abad drianage and samples of ps formation, were simillar and parallel with samples of sedimentation bassin. Also, they show good genetic relationship in scatter diagrams.This shows that sources of fine grain sediments of spreading flood station are from soils of ps formation at the end of Naser Abad drianage, Gand tapeh and Gavzian villages. Base on the result of this study and other surveys, first, studing R.E.E will be useful for provenance of sediments, and second, diffrent subwatersheds which are producing simillar minerals, studying their by X.R.D is not helpful and no produce reliable results.