抄録
A knowledge of statistical analysis plays an essential, role in expressing varied characteristics in quantity and revealing informations about ore deposits genesis. In this regard, we have applied some statistical methods to grade of orebodies in the Liwu copper deposit in order to establish the characteristics of grades for a metallogenetic model. Three data sets were analyzed. Data set 1 contains assays of orebodies A1A2B1B2 from the upper mineralized zone, data set 2 contains assays of orebodies B3B4B5CD from the middle zone, and data set 3 contains assays of orebodies E1E2E3E4 from the lower zone.
The frequency distributions of grade data suggest that all distributions are highly skewed and theoretically close to the lognormal. This trend of grade for the deposit strikingly indicates a main metallization phase, slightly superimposed by the later metallizing process. Meanwhile, the statistical characteristics indicate clearly that the middle mineralized zone represents the most profitable section of this deposit. The statistical tests concerning grade variances and means manifest that orebodies from the three zones were formed from the same mineralization process, rather than different ones developed by some previous researchers. Consequently, three zones are different sections of a mineralized zone, which strongly agrees with a recent structural viewpoint that orebodies of the Liwu copper deposit are controlled by one homocline recumbent fold. The grade model analysis shows that there is a strong similarity between the Liwu copper deposit and Besshi massive sulfide copper deposits.
