Редкоземельная минерализация Печальнинского вулканического комплекса (Северо-Восток России)

The article presents the first data on rare-earth element-concentrating minerals in the Campanian Pechalny volcanic complex (Magadan Oblast). The volcanic complex is composed of a series of small subvolcanic rhyolite and trachyrhyolite intrusions, their explosive breccias, and basalts lava flow, which, judging by geochemical data, belong to typical intraplate bimodal magmatism. Rhyolites are extremely enriched in rare-earth elements of the lanthanide group (average REE total = 1152 ppm, max. up to 5662 ppm), as well as in Rb, Zr, Y, and Nb. The main rare-elementconcentrating minerals are monazite, allanite (orthite), gel-zircon, as well as Nb-bearing rutile and hematite. All minerals, except allanite, are characterized by a small grain size, from 15 μm to 2 μm and less. Unusual spheroid gel-zircon have been discovered; their genesis is associated with the hydrothermal stage of volcanism, at high oxidation state in a highly concentrated supercritical fluid.