BOWEN'S REACTION SERIES PART 1

As a geologist, one should understand how the magma at different temperatures behave. Because the order in which minerals crystallize from a basaltic magma depends on the temperature, according to well famous Canadian Geologist Bowen. Understanding the reaction of the rock forming minerals will help you understand the chemistry of magma. The Bowen's reaction series is divided into both continuous and discontinuous serieses, and the two branches vary in terms of the structures. Continuous branch minerals have continuing same structure whereas discontinuous branch has minerals which have varying structures, from sheet to isolated. The first minerals to crystallize in each branch are the high stable temperature minerals such as olivine and Ca-rich plagioclase, but due to the undercooling of the magma, the early formed minerals will react with the melt to form new stable minerals or phases at that temperature of interest, only when the early formed minerals are permitted to react with the melt to form new phases, we talk about equilibrium crystallization . Should the early formed minerals get to be removed from the magma chamber, the liquid composition will now evolve as it runs away from early crystallizing phases forming the magma of felsic in composition, then now we start talking about crystal fractionation.

Visit: Tulane University Bowen's reaction series and Introduction To Igneous and Metamorphic Petrology OHN D. Winter