Anomalía geoquímica de los granitoides calcoalcalinos hercínicos del área Cáceres-Salamanca-Zamora (España). Implicaciones petrogenéticas

Abstract

An exhaustive geochemical study of the calc-alkalic igneous rocks of Western-Central zones of the Hesperian Massif have been carried out, clearing up the existence of a great compositional anomaly, which essentially consists of a high content in K, Li and Rb; low K/Rb ratio and a high Ba/Sr ratio. It is inferred that such anomaly is really concerned with the chemical character in the original melts, being useful to precise some important aspects of the anatexis mechanism. Its interpretation involves thermodinamical melting conditions about 900°C and 9Kb. Fusion has been developped on a rock with amphibolitic mineralogy and chemical composition similar to a continental andésite, yielding a residue with pyrigarnitic or hornblendic granulite affinities.