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Volume :2 Issue : 1 1975
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ON THE MINERALOGICAL CLASSIFICATION OF ZAKER GRANITIC ROCKS OF
Auther : ADEL M. REFAAT
Teachers Institute of Education, El-Odylia, Kuwait
Abstract.
A generalized geological map of Zaker area is constructed for the first time to the scale of 1:100,000 upon analysing data collected from the field. The granitic rocks of Zaker batholith comprise 37 petrographic varieties ranging from granites to diorites and passing through adamellites and granodiorites. The presence of myrmekite rims around the feldspar megacrysts of the leuco varieties of the examined granites is attributed to the effect of metasomatic processes with exsolution in the margins of megacrysts. The significance of red coloration of some granites of Zaker area is due to the iron ores resulting from the alteration of biotite and the enrichment in iron oxides during the effect of late hydrothermal solution. The petrographic classification agrees to a great extent with the classification based on the modal analyses of the examined granitic rocks, which comprise granite, syeno-grenite, monzo-granite, granodiorite, quartz-diorite and diorite. The present author is inclined to consider that the examined granites and adamellites are mainly of magmatic origin.