Выпуск: 2 , Том: 76 , Год издания: 2002

A strong correlation between the chemical composition of kimberlites and their diamond grade has been established using statistical methods. The investigation is based upon major element analyses of kimberlite samples, from which xenoliths have been removed. The samples represent highly diamondiferous, moderately diamondiferous, slightly diamondiferous and diamond-free rocks from diatremes of the Yakutian Kimberlite Province. In total, the investigation comprises 3792 whole-rock analyses and 1176 determinations of diamond grade. By means of correlation analysis, the kimberlite chemical analyses were subdivided into 113 clusters. Regression analysis was carried out between mean major element oxide concentrations of the clusters and the corresponding average values of diamond contents. The combined use of the regression method with a breakpoint and generalized nonlinear discrimination analysis has allowed to correctly estimate the average diamond grade of kimberlite clusters in more than 85-90% of the cases. The established statistical relations are convincingly justified from a petrological point of view. The reliable petrochemical description of kimberlite variety, based on averaging 25-30 whole-rock analyses or on analyzing of a sample obtained as a result of sequential quartering of a much larger sample, allows to estimate safely its diamond grade using major oxide contents. The method has worldwide application potential. (C) 2002 Elsevier Science B.V. All tights reserved.