Petrography, geochemistry and petrogenesis of alkaline dyke rocks from the Coldwell Alkaline Complex, Northwestern Ontario / by David G. Laderoute

Abstract

Dyke rocks occurring in the Coldwell alkaline instrusive complex, N. W. Ontario, were studied by various petrographic and geochemical means. The resulting observations indicate that 5 types of mafic alkaline lamprophyres, distinguished on the basis of chemistry and mineralogy according to the scheme of Rock (1977), and 1 type of felsic tinguaite occur in the complex (in approximate order of abundance): a) ocellar camptonites b) analcite tinguaites c) quartz-bearing camptonites e) amphibole camptonites f) monchiquites Lamprophyres are characterized mineralogically by phenocrysts of clinopyroxene and brown amphibole, and remnant phenocrysts of olivine...(see document for full abstract)