PEG 2013: The 6th International Symposium on Granitic Pegmatites Abstracts Page 39 STRUCTURAL AND PARAGENETIC ANALYSIS OF SWARMS OF BUBBLE LIKE PEGMATITES IN A

Shallowly emplaced hydrated granitic magmas may produce miarolitic cavities, some of which are lined with minerals. Essential to the formation of miarolitic cavities is exsolution of a fluid phase that results from fluid immiscibility when Pfl> Plit. Whether volatiles escape or are entrapped within the melt is a function of both temperature and pressure. Entrapment is more likely if heat is rapidly dissipated from a rapidly cooling melt, thus miaroles are more common in fine-grained rocks. The less dense volatiles rise into the apical zones of a magma chamber when the degree of crystallization of the melt is low (e.g. Candela, 1997). The Ferreira de Aves pluton (Viseu) is a two-mica syn-to late tectonic granite associated with th