Modelo cinemático de interacción de megacristales de feldespato alcalino durante el flujo de magmas graníticos

Abstract

The alkaline feldspar megacrysts are an abundant element of granitic rocks, where they give place tomagmatic fabric s, and generate geometric interactions providing important information about flow mechanisms of granite magmas. It has been demonstrated in previous works that feldspar megacrysts behave as rigid objects that rotate and are displaced within a viscous matrix. The model presented in this work simultaneously uses the equations predicting rotation of rigid particles embedded in a viscous matrix that flows under combination of pure and simple shear (plane, monoclinic flow), and those determining the relative displacement of two or more particles for the same type of flow. The results for simulated marker pairs satisfactorily reproduce the distinct geometrical types of megacryst interaction observed in Nature when different values of the controlling parameters are considered (kinematic vorticity number, shape of markers, initial orientation and relative position of modelled megacrysts). Future improvements of the model and its application to the study of natural cases will allow better understanding of granite magma kinematics.