PETROLOGY OF MAFIC-ULTRAMAFIC LAYERED INTRUSIONS IN PRECAMBRIAN PLATFORMS: STATE OF THE ART AND NEW APPROACHES
E.G. Konnikov, A.A. Ariskin*, G.S. Barmina*, and E.V. Kislov**
Institute of Experimental Mineralogy of the Russian Academy of Sciences,
Chernogolovka, Moscow Region, 142432, Russia
* Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences,
19 ul. Kosygina, Moscow, 117975, Russia
** Geological Institute, Siberian Branch of the RAS, 6a ul. Sakhyanovoy, Ulan Ude, 670047, Russia
Keywords: Layering, cumulus, intercumulus melt, convection, compaction, percolation
Pages: 1319-1327
Abstract
Phase layering in mafic and ultramafic intrusions cannot be explained in terms of convection and accumulation in magma chamber as convection of melt rich in cumulus crystals is impossible. Intrusion of heterogeneous magma with 40-50 vol.% crystal phase is rather associated with compaction whereby intercumulus liquid is squeezed out toward the roof of the chamber.
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