PETROGENESIS OF HIGH-TEMPERATURE SILICEOUS MELTS IN VOLCANIC STRUCTURES OF THE ALTAI COLLISIONAL SYSTEM OF HERCYNIDES ( Eastern Kazakhstan )
S.V. Khromykh, M.L. Kuibida, and N.N. Kruk
V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Petrogenesis of siliceous melts, mantle-crust interaction
Pages: 411-420
Abstract
We consider the geologic occurrence and PT -conditions of the generation and crystallization of siliceous melts that formed volcanic structures within the Altai collisional system of Hercynides. The data on the geologic occurrence, internal structure, and petrogeochemical age of rocks are presented, as well as results of the thermobarogeochemical studies of inclusions in minerals. The performed investigations showed the presence of siliceous dacitic melts in the studied volcanic structures. These melts were generated in the lower crust (~10 kbar, 1000-1200 ?C) as a result of the partial melting of crustal substrates under the influence of high-temperature mantle melts.
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