Metasomatism associated with subduction-related, volatile-rich silicate melt in the upper mantle beneath the Nógrád-Gomör Volcanic Field, Northern Hungary / Southern Slovakia: Evidence from silicate melt inclusions
Szabö, Csaba; Bodnar, Robert J.; Sobolev, Alexander V.
European Journal of Mineralogy Volume 8 Number 5 (1996), p. 881 - 900
published: Oct 30, 1996
manuscript accepted: Apr 18, 1996
manuscript received: Oct 10, 1995
ArtNo. ESP147050805002, Price: 29.00 €
Abstract Metasomatized upper mantle xenoliths from the Nôgrád-GomÖr Volcanic Field (NGVF) of north Hungary and south Slovakia contain "andesitic" and "basaltic" silicate melt inclusions hosted mainly in olivines. Melt pockets occur interstitial to mantle phases. Other melt accumulations are spatially associated with ortho- and clinopyroxenes and amphiboles. Petrographic and geochemical data suggest a common source for these distinctly different occurrences. Of the possible origins for the melt in inclusions, melt pockets and other melt accumulations, the one that is most consistent with the available data is a subduction-related, volatile-rich silicate melt that infiltrated through and interacted with mantle phases, causing cryptic and modal metasomatism in the peridotitic wall-rock and a progressive evolution of the melt composition to produce residual melts. Formation of melt pockets and multiphase silicate melt inclusions with "basaltic" composition was associated with the less residual melts. Conversely, more evolved melts, enriched in silica, alumina, alkalies and CO2, percolated through the shallow lithospheric mantle with little or no interaction and were trapped as "andesitic" silicate melt inclusions.