These intergrowths are typical of pegmatite and granophyre, and they have been interpreted as documenting simultaneous crystallization of the intergrown minerals in the presence of a silicate melt together with a water-rich phase.
22.
Phenocrysts of feldspar occur occasionally and of quartz more seldom; but the relation of aplite to quartz-porphyry, granophyre and felsite is very close, as all these rocks have nearly the same chemical composition.
23.
In such occurrences, the granophyre may form as an end product of fractional crystallization of a parent mafic magma, or by melting of rocks into which the mafic magma was emplaced, or by a combination of the two processes.
24.
I'm sometimes missing something when reading a WP article ( an easy example : Granophyre ) and the subject pronunciation is described in IPA . I look at the the IPA symbols and have no idea how to pronounce the subject.
25.
During the formation of the volcanoes and their associated deposits of basalt and rhyolite there are melts that never reach the surface and these shallow level intrusions are notable in the forms of their non-extrusive equivalents such as granophyre and rhyolite.
26.
The St David's Granophyre has historically been incorrectly assigned to be alaskite or trondhjemite due to low concentrations of potassium feldspar but this has been shown to be an alteration product from its original calc-alkaline granite which is noted to exhibit a volcanic arc signature.
27.
The sediments of the Uriconian are indicated to have been deposited rapidly with such volcanism being dated ( U-Pb Zircon ) at 566 + /-2Ma ( Note the Uriconian is cross-cut by the Late Precambrian Ercall Granophyre dated 560 + /-1Ma . ) The sequence is dominated by pyroclastic deposits, breccias and welded tuffs which is suggestive of a former volcanic centre being in close proximity and deposition in a subaerial environment.
