Two‐Stage Mafic‐Felsic Magma Interactions and Related Magma Chamber Processes in the Arc Setting: An Example From the Enclave‐Bearing Calc‐Alkaline Plutons, Chinese Altai

Abstract

Granitoids are principal constituents of the felsic continental crust, and their formation is of fundamental significance in interpreting the generation, growth, and reworking of the continents. The petrogenesis of granitoids has long been hotly debated, involving multiple parental magma sources and the complex interplay between various magmatic processes. Specifically, some interpret that most post-Archean granitoids are of dominantly crustal origin, while others contend that there is mantle involvement, leading to the controversy over patterns of crustal growth (e.g., Arndt, 2013;Dhuime et al., 2012). The relative importance of fractional crystallization, crustal melting, and magma mixing is rather complex and may require case-by-case analysis. Calc-alkaline plutons in arc settings are special in that many of them retain textural and field evidence indicating the hybridization of compositionally diverse magmas (e.g., Wiebe, 1993). For example, widespread mafic microgranular enclaves (MME) within the calc-alkaline granitoids are mostly of igneous origin and sometimes associated with mafic dykes, representing quenched globules of a mafic magma (

Geochemistry, Rb-Sr whole rock age and Sr-Nd isotopic constraints on the Variscan A1-type granite from Azegour area in the Marrakech High Atlas (Moroccan Meseta) and their geodynamic implications

“…The heat required to melt the crust is provided by the rise of basaltic magmas derived from the mantle. These magmas can still interact, to varying degrees, with the residual and/or crustal rocks materials to form liquids with mixed signatures (e.g., Pitcher, 1983;White & Chappell, 1983;Brown et al, 1984;Pearce et al, 1984;Whalen, 1985;Cui et al, 2021).…”