Intrusion of Mafic magmas Into Felsic Magma Chambers: New Insights from Natural Outcrops and Fluid-Mechanics Experiments

摘要: The injection of mafic magmas into felsic is studied focussing on three natural case studies in which the process was frozen at initial stages. contact morphology between magmas is strongly variable each outcrop and has been quantified by the fractal dimension. Natural morphologies are identical to those produced «viscous fingering» where a low viscosity fluid displaces high viscosity one. Viscous-fingering fluid-mechanics experiments have been performed using fluids with different ratios. A very good empirical exponential relationship found between fractal dimension experimental structures ratio. Using derived from experiments, and using values measured samples, the ratios estimated. Results indicated that highly coexisted in studied magmatic system. These results have explained hypothesizing heating magma by continuous inputs of high temperature magma. Such may explain and physically justify decrease contrasts magmas as proceeds time. Results this study give new insights potential evolution mixing processes plutonic environments. In fact, it suggested viscous fingering be very important process contributing drifting ratio magmas towards and, hence, towards best rheological conditions to trigger widespread chamber. We show combining geometry measurements on natural rocks help shed new light geological whose knowledge open new frontiers igneous systems their evolution time and space