Zeolitas y minerales cálcicos de baja temperatura en las pegmatitas graníticas del plutón de La Cabrera (Sistema Central Español)

A late hydrothermal activity in the La Cabrera granitic pluton developed in some miarolitic cavities and pegmatites several mineral associations according to the temperature decreasing. Among these associations, the calcic medium-low temperature have a special interest. They are unique in the Spanish Central System. The characteristic minerals, beside calcite, are prehnite, laumontite, heulandite-(Ca), stilbite-(Ca), chabazite( Ca), fluorapophyllite, datolite and bavenite. All minerals are characterised by X-ray diffraction and thermal analysis. Their chemical compositions are studied, including babingtonite, an accessory mineral in these associations. The maximum hydrothermal activity occurred at 250 ± 50° C decreasing towards 140° C. During the cooling an increase of f CO 2 produced calcite.