Basalt-crust interaction processes: insights from experimental petrology

Abstract

The evolution of magmas has been one of the focal point of petrological studies since the first decade of the past century. Simple processes, such as fractional crystallization, mixing, and mingling, although well documented, do not fully explain the chemical peculiarities of many magmas [Barley, 1986; Knesel and Davidson, 1996; Lassen et al., 2004; Dungan and Davidson, 2004; Tegner et al., 2005]. For example, more complex processes must be invoked in the case of magma-crust interaction, e.g. assimilation and fractional crystallization (AFC), assimilation and equilibrium crystallization (AEC), recharge assimilation and fractional crystallization (RAFC), recharge tapping and fractionation assimilation RTFA, to explain geochemical, isotopic, and, to a minor extent, major elements features [Hildreth and Moorbath; 1988; Spera and Bohrson, 2001]. Interpreting the elemental and isotopic compositions of mantle-derived magmas in terms of mantle processes and determining how these relate to the magma ascent and emplacement, depends on recognizing that the geochemical signatures imparted by magma generation processes into the source, may be overprinted by open-system processes during intracrustal evolution.