The development of petrologycal, mineralogycal and geochemical prospecting criteria of the rich ilmenite ores in the magmatic rocks of the Ukrainian Shield

By the results of study of ilmenite deposits and occurrences related to the anorthosite-rapakivi granite plutons (ARGP) of the Ukrainian Shield (USh) have shown that the type of mineralization dependents on a rock type. The essentially ilmenite mineralization is observed in the "norite" gabbroids type, while ilmenite-apatite - in the "troctolite." It is concluded that for mainly ilmenite deposits the initial magmatic melts were somewhat different with respect to the apatite-ilmenite gabbroids (ijotunite - in the first case, and enriched in titanium subalkaline basalt - for others). In addition, the available geological data and mineral composition indicate that the rich ilmenite ores crystallized under reducing conditions (oxygen fugacity was obviously lower than the quartz-fayalite-magnetite buffer), whereas apatite-ilmenite ores formed in a more oxidized conditions (as result titanomagnetite and Ti-augite appearance). Mineralogical investigations of the rich ilmenite ores of USh indicate on a significant difference between their rock-forming and ore minerals in comparison to well known foreign deposits and majority deposits of USh. For example the rich ilmenite ores of Nosachiv deposit and Penizevichy occurrence are different from similar deposits: almost pure stoichiometric ilmenite composition; absence of magnetite and apatite inclusions in ilmenite, which allows to produce the pure ilmenite concentrates; more Fe-enriched composition of pyroxene composition in comparison to foreign deposits. First is revealed the unusual significant deep negative Eu-anomalies in the chondrite-normalized REE patterns from apatites of these deposits than they are distinguish from apatite from the majority of apatite-ilmenite deposits of the USh and  the large ilmenite deposits of the world. It is revealed that REE distribution in the chondrite-normalized patterns of apatites have the individual differences that is connected with peculiarities of a deposit mineralization. This can apply as a criterion of diagnostics and prospecting of the ore-bearing rocks in different complexes. Study of the isotopic composition Sr (87Sr/86Sr) in apatites are also marked differences in the Sr isotopes ratio from deposits of ARGP USh with different mineralization types. By result of investigation have been distinguished the geological, petrological, mineralogical and geochemical criteria of prospecting for rich ilmenite ores. The obtained criteria together with the analysis of the geological structure of the USh allows scheduling the most perspective locations for search of the rich ilmenite deposits.

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0110U005310

Роки виконання: 

2010 до 2012