منشاء‌یابی کلوئیدهای رسی و سیلتها در ایستگاه پخش سیلاب کبودرآهنگ بااستفاده از عناصر نادر خاکی

Abstract:

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 ۱۵۰۰۰ ton sedimentary clay and silte during two floods in spreading flood station of kabudar ahang and decreasing the permeability rate about ۰.۳۵ cm/h (Yaghubi,۲۰۰۰), 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 ۶۰ samples from fine sediments main drianage, spreading flood area, sedimentation bassin and soils. Also, ۱۸ lithic samples were obtained from different lithologies, of which ۸ samples analyzed by the method of x-ray differactometery (X.R.D). Another ۱۸ samples analyzed by the method of neutron activation analysis to calculate R.E.E rate, "th" and "Sc" elements. There is also ۹ samples analyzed by the method of  producing thin section. at first, geological map was drawn, by the help of results, second R.E.E 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 "La/th" , "th/sc" rates were also drawn and studied. results were:pattern 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.