A petrochemical criterion of diamond potentials of heterochronous kimberlites and lamproites

Statistical processing of data of 4180 silicate analyses of kimberlites fro m 250 diatremes and 325 chemical analyses of lamproites from more than 50 b odies from different regions of the world was carried out. The author has e stablished a positive correlation of the diamond potential of these rocks w ith their elevated MgO/Sigma FeO ratios and magnesium coefficients and redu ced SiO2/MgO ratios, acid contents, and values of some other petrochemical coefficients. The revealed regular correlation Is observed in both separate occurrences of these rocks and their fields. Highly diamondiferous kimberl ite and lamproite fields in each province have their own age criterion, and the increased diamond potential of pipes is related to the deeper and youn ger phases of magma melt intrusion of certain tectonomagmatic cycles. The petrochemical criterion of diamond potential is graphically reflected o n a binary diagram as a field of highly diamondiferous kimberlites with ave rage MgO/Sigma FeO = 2.9-4.1 and SiO2/MgO = 0.9-1.8 and an adjacent trend o f figurative points for olivine lamproites of increased diamond potential w ith average MgO/Sigma FeO>2 and SiO2/MgO < 4.