ILMENITAS KIMBERLÍTICAS DA MINA DE DIAMANTES DE ROMARIA, MG

DARCY P. SVISERO, HENRY O. A. MEYER

Resumo


Magnesium ilmenires have been found in the diamond bearing conglomerate croping out the city of Romaria, Minas Gerais State. The ilmenites are associated with other heavy minerals, including magnetite, hematite, limonite, staurolite, zircon, pyrope knorringite and almandine grossular garnets, tourmaline, epidote, kyanite, monazite, corundum, anatase, hornblende, and rutile as well as diamond.
Microprobe data (29 analyses) indicate that the ilmenites have MgO and Cr2O3 ranging from 7.0 to 12.5 and from 0 to 3.5%, respectively, and contents of Al2O3, CaO and MnO usually lower than 0,5%. Thus, the Romaria ilmenites are similar in chemistry to ilmenites of kimberlite concentrates and, also, to ihnenites of ultramafic xenoliths from kimberlites of worldwide localities. On the other hand, physical characteristics of the ilmenites and other associated kimberlitic minerals clearly suggest the presence of diamondiferous kimberlites nearby Romaria.

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