aphyric

aphyric

[ā′fir·ik]
(petrology)
Of the texture of fine-grained igneous rocks, showing two generations of the same mineral but without phenocrysts.
References in periodicals archive ?
The mafic dykes are porphyritic to aphyric and consist of calcic plagioclase, hornblendic amphibole or clinopyroxene +/- olivine, ilmenite, titanite and a range of secondary minerals.
The Endeavour Seamount lava is highly plagioclasephyric, but all others are aphyric to sparsely phyric (plagioclase +/- olivine, rare clinopyroxene).
The settling and flotation of cumulus crystals is also restricted to low viscosity aphyric magmas, which would allow rapid and unimpeded vertical movements of cumulus crystals.
They present quartz and K-feldspar phenocrysts in an aphyric matrix composed by quartz, K-feldspar(orthoclase?
This plutonic complex (cumulates, gabbros and plagiogranites) is intruded by various stages of dykes with chilled margins: 1) scarce ouralitized dolerites; 2) olivine basalts; 3) aphyric basalts.
Unit F is composed of essentially aphyric basalt of varied petrography and chemistry, which suggests that it consists of at least two flows, although they were not distinguished in the field.
This host unit is underlain by a sequence of aphyric andesite or latite volcanic flows which to date have not been found to host mineralization.
The mafic rocks are porphyritic to aphyric and consist of calcic plagioclase, clinopyroxene +- olivine or hornblendic amphibole, ilmenite, titanite, and a range of secondary minerals.
The marginal zones of the dyke are aphyric and free of xenoliths and megacrysts, both of which were concentrated in the dyke interior by flow differentiation and show varying degrees of flow alignment (Fig.
This is close to the composition of aphyric komatiites and chilled margins of komatiitic flows.