Metamorphic carbonate–mafic amphibolite interactions from Arinteiro, northwest Spain

Some contacts between interlayered marbles and amphibolites at the Arinteiro copper mine are associated with zoned metasomatic calc‐silicate assemblages. Textures indicate that formation of the calc‐silicate zones involved mass transfer over distances up to 15 cm and that pore fluid solution (infiltration) may have been a significant reaction mechanism. The sequence of minerals is very similar to previously described products of metasomatic interactions between marbles and pelites. Similar metasomatic processes involving primary concentrations of carbonates can be invoked to explain the common occurrence of zoned calc‐silicate patches and folia in metaigneous amphibolites both near Arinteiro and in other terrains.