Abstract
In his comments on my paper, Dr. Garg reinterprets my observations of the myrmekites of the S.W. Nigerian charnockites to conform with Shelley's (1964) hypothesis of myrmekite growth by incorporation of intergranular quartz in exsolving albite. For many reasons I found Shelley's proposals unacceptable for the myrmekites I studied. Perhaps the most striking feature opposed to Shelley's development scheme is the fixed proportionality of quartz to plagioclase found throughout the undeformed myrmekites in any one rock of my series (Hubbard 1966, p. 772). Continuing work on this feature serves to confirm this proportional relationship of components, controlled by the composition of the plagioclase component of the myrmekite. Dr. Garg singles out for reinterpretation the fine polyfurcated quartz zone at the myrmekite-alkali feldspar interface reported and illustrated in my article (Fig. 4 and 5). This remains, to my mind, one of the most compelling petrographic features indicative of coprecipitation of the plagioclase and quartz synchronous with the advance of the growth front into the source alkali feldspar (p. 772). Dr. Garg's contention that “ . . . quartz away from the contact will have ample space to recrystallize ...” pin-points, I feel, a difficulty in Shelley's interpretation of myrmekite growth; the problem of space availability.
