Petrogenetic analysis of fluid and melt inclusions in minerals from mantle xenoliths from the Bele pipe basanites ( North Minusa depression )
A.V. Golovin, V.V. Sharygin
Institute of Geology and Mineralogy, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Fluid and melt inclusions; mantle xenoliths; basanites; melts
Pages: 811-824
Abstract
Results of study of different types of inclusions in minerals from mantle xenoliths from the Bele pipe basanites are presented. Two groups of inclusions were recognized in the host minerals according to their genesis. The first group includes single, apparently primary, fluid inclusions. They were discovered only in orthopyroxenes and consist of CO2 (95 mol.%) and N2 (5 mol.%). These inclusions had partly leaked. The densities of two least leaked inclusions from different xenoliths are 1.05 and 1.14 g/cm3, and their trapping pressures are estimated at >8.5 and 12 kbar, respectively. The second group includes syngenetic secondary fluid, melt, and crystalline inclusions. In composition the secondary fluid inclusions differ from the primary ones in higher concentrations of N2 (up to 7 mol.%). Their maximum density is 0.57 g/cm3, which corresponds to 2.4-2.6 kbar and 1100-1200
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