Underplating of the crust by mafic magma can lead to partial melting and production of felsic magma
. Kochhar et al.
The MMEs sometimes show core-tail structures, in which the tail displays an S-shaped bend, suggesting that they were at least partly plastic when introduced into the felsic magma
Barnes, 1986; Bedard, 1994; Charlier et al., 2005; Bernstein, 2006) and if an external component, such as an evolved melt associated with wall rock assimilation or felsic magma
hybridization, plays a major role (e.g.
Mass-balance analysis (model A) for SC northern sector has showed that from ~11 to 58% of the andesitic end-member was partially mixed with the felsic magma
, as observed in Q diagrams (Figure 13).
Earth scientists from Europe, Australia, and North America pursue such questions as how long magma is stored in a reservoir before eruption, how long it takes to evolve from mafic to felsic magma
compositions, how long it takes for a magma generated in the mantle to reach the surface, and how long after the Earth was created did a metallic core form.
Mesoscale pervasive felsic magma
migration: alternatives to dyking // Lithos.
An effective blending is inhibited when temperature and viscosity contrasts between two magmas are large and when the proportion of the mafic/intermediate end-member magma is small (typically < 50%), because the mafic/intermediate magma is undercooled to form isolated magmatic inclusions or enclaves in the felsic magma
(Eichelberger, 1980; Bacon, 1986; Sparks and Marshall, 1986; Vernon et al., 1988; Stimac et al., 1990; Clyne, 1999; Gencalioglu Kuccu and Floyd, 2001; Coombs et al., 2002; Alpaslan et al., 2005).
Rheological transitions during partial melting and crystallization with application to felsic magma
segregation and transfer.
The papers in this special issue result from a theme session on "Processes in felsic magma
chambers--from crystallization and evolution to emplacement" that was convened at the joint meeting of the Northeast Section of the Geological Society of America and the Atlantic Geoscience Society, March 27th-29th, 2003, at the Westin Hotel, Halifax, Nova Scotia.
Water lowers the temperatures that are required for the partial melting in the mantle wedge, which produces mafic magma, and in the crust, produces felsic magma
. Arc magmatism is intimately related to metamorphism, although this relationship is complicated largely because maximum pressures and temperatures are attained at different times.
Trace-element modeling, major-element chemistry, and petrologic evidence indicate that the MBG and MPG may have formed through pulse injection of magmas produced by fractional crystallization from felsic magma
chambers at depth, involving an assemblage of clinopyroxene, amphibole, plagioclase, K-feldspar, [+ or -] blotite, [+ or -] zircon, [+ or -] apatite.
Hibbard (1995) suggested that boxy cellular plagioclase grains form when plagioclase, originating from the mafic material, comes in contact with the cooler, felsic magma
. The plagioclase then becomes converted to more sodic compositions as equilibration occurs.