While the felsic dykes are apparently related to the granite, the mutual relations between the granite, mafic and rhyolite sheets are yet to be deciphered, but the rhyolites may represent melts derived from the crust through underplating by mafic magma
Unfractionated HREE (and Y) patterns generally suggest that the mafic magma
was possibly produced outside the garnet stability field (i.
2000) suggested that, if ponding mafic magma
operates like a rising piston, co-mingled lavas are slowly expulsed reaching the surface by a volatile-poor and non-explosive effusive eruption.
Experimental and observational evidence suggest that olivine, followed by clinopyroxene and plagioclase, are the earliest crystallizing phases from mafic magma
A late influx of mafic magma
disrupted older mafic rocks and hybridised with granite, producing complex, heterogeneous "diorite".
The Tertiary Capitan dike swarm appears to represent the emanations from a crystallizing and differentiating mafic magma
chamber or chambers that were episodically replenished by influxes of basaltic magma.
Are these youngest granites a result of partial melting of the country rocks by the rising mafic magma
or did the waning phases of the granite magmatism overlapped with mafic magmatism?
Arcs under extension have a steep geothermal gradient and underplating of the crust by mafic magma
may transfer sufficient heat to induce anatexis.
A likely model is that a mafic magma
(possibly mantle derived) of the MPS was emplaced first and underwent substantial crystal fractionation to produce the mafic and ultramafic St.
Hybrids dominated by the crustal melts are expressed by the various facies of the Monte Capanne pluton, whereas the mafic magma
hybrids are represented by the ubiquitous presence of a wide variety of mafic microgranular enclaves.
In these "fossil", high-level magma chambers, such as the Pleasant Bay Complex (Wiebe 1993a), field relations indicate that mafic magma
was episodically injected into the crystallizing felsic magma chamber.
39] studies of these rocks record episodic deformation and varying degrees of metamorphism up to lower amphibolite facies, and a protracted history of mafic magma
injection from a similar source beginning in the Early Silurian.