COMPARISION OF THREE ANALYTICAL METHODS OF GRAIN GRADE

Analysis of grain grade is widely used in geology for studying sedimeust transimition and sedimental environments. Besides the conventioned sieve analysis, there occure some new methods, such as computer-controled IAS-FLUS image analysis instrument and the microscope combined with WDJ.But wich one is the most economically benificial method and how to improver the analytical speed and precision.In this study, some different samples have been analysed with the three methods and the results fiave been coprnared.Some conclusions obtained as follow:1. Sieve analysis is suitable for cohesionless sandestone especially for wind, river, lake-formed sandstone after Cenozic and Mesozoic,2. TAS-PLUS image aualysis instrument is beter for quartz-sandstone, fundamentally cemented saudstone, striped sandstone and differently lighted sandstone. 3, The microscope combined with WDJ is suitable for most kinds of sandstone.Even though it could be widely used. the oberservating is very difficult under microscope and influnced by some manal factions.So, using a suitable method is important for benified sample analysis.