MANGANESE AS AN INDICATOR OF MANTLE HETER OGENEITY BENEATH THE SIBERIAN KIMBERLITE PROVINCE

Manganese is a minor component in both kimberlites proper and in their abyssal minerals. Locally, an enrichment in manganese is recorded in ilmenite from carbonate-rich parts of kimberlite pipes and in rims on ''usual'' ilmenite. The lack of apparent regularities in the geochemic al behavior of manganese (from data of many publications) can be possi bly accounted for by analytical errors. Certain parts of the Siberian kimberlite province (fields, pipe clusters. and individual pipes) diff er from one another in Mn contents and of the Mn/Fe ratio in garnet, i lmenite, chrome spinellids and the kimberlites proper. A symmetrical z onation was established in the distribution of Mn/Fe ratios in the Kuo yka field, and a direct correlation between Mn/Fe ratios and Cr conten ts in garnets and chrome spinellids was detected. A significant (r = 0 .62-0.79) direct correlation between Mn and P, Sr, Ba, Y, La, Th, U, N b, and Ta concentrations was revealed in the examined collection of th e Siberian province kimberlites. This correlation is stronger than the correlation between Fe and the same elements (r = 0.30-0.68). The enr ichment of the kimberlites in manganese was, obviously, partly related to mantle metasomatism.