Аннотация:EXPERIMENTAL STUDY OF MALIGNITE FROM LOVOZERSKIY MASSIF MELTING
SUK N.I., KOTELNIKOV A.R., POLSKOY P.F.
Institute of Experimental Mineralogy RAS, Chernogolovka Moscow district, Russia
Malignite is the rock which contains rich loparite ores in Lovozerskiy massif. Experimental study of melting of malignite from Lovozerskiy massif has been produced at T=1250oC and 3 kbar in high gas pressure vessel with duration of 6 h in presence of 15 wt% H2O. The experimental samples were analyzed on a digital scanning electron Tescan Vega II XMU microscope.
It was obtained the immiscible splitting into two liquids: aluminosilicate one, which formed matrix, and droplets, enriched in Ti, REE, Sr and Nb. Size of drops varies from 1 to 5 mkm. This fact can be explained by generation of liquid immiscibility which was previously obtained (Suk, 2007, 2012) in model aluminosilicate alkaline magmatic systems, containing REE (La, Ce, Y), Sr and Nb at T=1250oC, P=2 kbar in presence of water or alkaline fluid.
In malignite melting products the sphere of ore melt with heterogenic structure which also can be explained by titanate-silicate liquid immiscibility has been observed, too.
Moreover in one of the malignite samples from Lovozerskiy massif the part which presents matrix with including crystals of rock-forming minerals was obtained. This fact can be explained by crystallization from two-phase melt.
So, experimental data obtained show that magmatic melt can considerably enrich in ore components by arising of titanate-silicate liquid immiscibility. It can have important significance for formation of rich REE-Nb (loparite) ore deposits at magmatic stage.
References
Suk N.I. Experimental study of alkaline magmatic aluminosilicate systems with connection of genesis of REE-Nb loparite ore deposits. Dokl. Akad. Nauk. 2007. V. 414. N 2. P. 249-252.
Suk N.I. Liquid immiscibility in fluid-magmatic aluminosilicate systems contained Ti, Nb, Sr, REE and Zr (experiment). Petrologiya. 2012. V. 20. N 2. P. 156-165.
