Time Series to Petrogenesis: Analysis of Oscillatory Zoning Patterns in Plagioclase Crystals from Lava Flows

In this contribution we present preliminary results of analyses of plagioclase oscillatory zoning from three different lava flows cropping out on the island of Capraia (Tuscan Archipelago, Italy) with the aim of understanding the causes of the oscillatory zoning. Analysis are performed using a new method that combines microanalysis with image analysis and allows us to extract compositional time series with high spatial resolution along the zoning profiles. Compositional time series are analysed by the Detrended Fluctuation Analysis (DFA) method and results indicate that most zoning profiles in the studied lava flows can be regarded as having the property of 1/f-noise. By using a simple dynamical system, the logistic map, it is shown that this property can be attributed to self-organized criticality, i.e. a feature typical of systems lying at the boundary between stability and chaos. It is suggested that the statistical properties of plagioclase oscillatory zoning may be explained by continuous restructuring of flow fields in the magmatic system due to variations of the geometrical configuration in which the magmatic processes occurred at different times. It is suggested that analyses of compositional time series extracted from plagioclase crystals may be used as an additional petrological tool to better understand the complex processes occurring in magmatic systems.