GEOLOGY OF CENTRAL ARAGUA, VENEZUELA

Abstract

The Central Aragua area is on the southern flank of the mountain ranges of north-central Venezuela. The south boundary of the map area separates the mountainous metamorphic zone from the low hills and plains underlain by unmetamorphosed rocks to the south. Most of the area is underlain by a sequence of metamorphosed volcanic rocks more than 3000 m thick, the Villa de Cura group. This sequence has been subdivided into four conformable formations. The lowest three formations (El Cano, El Chino, and El Car-men) consist of metamorphosed spilitic basalts and associated volcanic sedimentary rocks. These rocks are now greenstones, some of which contain glaucophane. A striking feature of the metalavas is the presence of unaltered augite. The uppermost (Santa Isabel) formation is considerably more siliceous than the lowest three formations and consists of chlorite-quartz-albite schists and granulites; many rocks contain glaucophane. The Santa Isabel rocks closely approximate keratophyre lavas in chemical composition but are clearly of sedimentary origin. Dioritic rocks intruded into the Santa Isabel for-