The total number of nuclei, Z, of a single phase formed in a unit volume of a crystallizing magma at the distance y from the contact of a semi-infinite intrusion is[Formula: see text]where n is a numerical constant determined by growth controlling process during the nucleation period and the value of m in the expression assumed for the nucleation rate, J[Formula: see text]The observed variation of Z for clinopyroxene and plagioclase from the contact towards the center of two large dikes appears to follow this relation. In the 106 m wide Kigaviarluk olivine tholeiite dike the value of n is significantly greater for the clinopyroxene (−2.2) than the plagioclase (−0.84). In the 60 m Grenville dike, a quartz tholeiite, the n value (−1.5) is the same for both minerals. The growth-controlling mechanisms of plagioclase and clinopyroxene appears to be sensitive to the bulk composition of the magma from which it is crystallizing.
Crystal Growth Mode Changes during Pulsed Laser Induced Rapid Solidification in Nanoscale Thin Films of Al-Cu Eutectic