Magmatic plume on lavadores granite (V. N. Gaia, NW Portugal)

The Lavadores Granite shows a feldspathic plume structure that is an association of an irregular mafic tonalitic layer with an exotic K-feldspar crystallization, plus a heterogeneous nucleation on the tonalite boundary and a dendritic and comb grown, representing an almost completely continuous structure. The observations lead to the hypothesis that the dendritic plume structure crystallization is a result of specific conditions inside schlieren and in their vicinity. The plume structures seem to be crystallized freely inside the open tonalitic layer/schlieren and the model of “hollow space” at the transition zone would explain this free crystallization of the plume structures