Alkaline monzo-syenitic porphyries from the Spanish Central System: relationship with the accompaninglamprophyres

摘要

The alkaline monzo-syenitic porphyries from the Spanish Central System (SCS) show a heterogeneouscomposition ranging from basic to acid terms which give rise to major and trace element compositionaltrends in accordance with fractional crystallization of amphibole, plagioclase, biotite, alkaline feldspar, Timagnetiteand apatite. The whole-rock geochemistry of the basic porphyries shows clear similarities withrespect to the SCS isotopically enriched alkaline lamprophyres, indicating that a genetic link between bothgroups of dykes might exist. This relationship would probably represent an origin of the monzo-syeniticporphyries after differentiation of parental lamprophyric magmas due to fractional crystallization