The distribution Cr, Ni, and chromite in komatiites, and application to exploration for komatiite-hosted nickel sulfide deposits

A comprehensive review of literature on the data on Ni and Cr contents in komatiites reveals that barren and mineralized komatiite sequences show contrasting trends on plots of Cr versus Ni. Barren komatiite sequences, on the average, have substantially higher Cr contents and Cr/Ni ratios than mineralized sequences. This contrast is due to the strong association of mineralization with volcanic facies involving channelized flow, and there is no such contrast between barren and mineralized flows within samples from channelized flow environments. Ponded sheet flow and lava lake sequences, with low potential for hosting economic nickel sulfides mineralization, can be discriminated on the basis of their statistically higher Cr contents and Cr/Ni ratios than more prospective sequences.