The research suggests that formation of adakite has various reasons including partial melting of subducted oceanic crust, crystallization differentiation of mantle-derived basaltic magma, migmatization
of magma, partial melting of delaminated lower crust and partial melting of thickened lower crust.
6) constrain the thermal evolution of the region much better as they yield concordant ages, within the error limits, for the migmatization
of gneisses is demonstrated by the evolution of significantly striped rocks formed by melanosome abounding in biotite and leucosome consisting of quartz, plagioclase and, to a lesser degree, of potassium spar.
The degree of migmatization
increases toward the centre of the gneiss, away from the exposed contacts with the surrounding plutonic rocks.
The peak of pressure is locally followed by a peak of temperature (about 700degC) at constant pressure that lead to the migmatization
of metasediments in Danba.
Disequilibrium melting and the rate of melt residuum separation during migmatization
of mafic rocks from the Grenville Front, Quebeq.
Pegmatites with quartz, microcline and mica are found in several areas of strong migmatization
is generally common and strong in places.
The origin of this lineation is also connected with ductile movements during incipient migmatization
, or during incipient partial melting of the original paragneisses.
As exemplified by detrital U-Pb zircon geochronology, the domes mostly comprise Paleozoic and Early Mesozoic metasedimentary rocks, which experienced Barrovian metamorphism with local migmatization
(~600-700degC, ~9-14 kbar).
Melting and diffusion processes in closed-system migmatization
The contact of the supracrustals with the gneissic complex is generally concordant and marked by intense migmatization
(Swaminath and Ramakrishna, 1981; Radhakrishna and Vaidyanadhan, 1997).