Santo Antonio Da Barra (Rio Verde)
Essentially a volcanic province of flows, pyroclastic deposits and numerous vents and plugs covering in all some 300 km2.
Essentially a volcanic province of flows, pyroclastic deposits and numerous vents and plugs covering in all some 300 km2.
Catalao II lies 15 km north of Catalao I and detailed descriptions are not readily accessible. It forms a circular dome with an approximate area of 14 km2, with a strong aeromagnetic expression. The country rocks are Precambrian quartzites and schists which are fenitized.
Catalai I is an approximately circular complex covering 27 km2 and lying 15 km south of Catalao II. It is emplaced in mica schists and quartzites of the Precambrian Araxa Super Group, which it fenitizes.
This is a neck of 'ultrabasic-alkaline' rocks occurring southeast of Coromandel; little known.
A small volcanic chimney cuts slates of the Bambui Group. Described as 'alkali olivine basalt', but contains perovskite, biotite (10%) and serpentine (35%), with some zeolite (Barbosa et al. 1970).
This occurrence comprises a dyke of ijolite and a chimney of olivine basalt.
Picritic and feldspathoidal alkali basalts occur, probably as necks; poorly known.
A large oval complex of about 65 km2 is emplaced into quartzites and phyllites of the Precambrian Bambui Group, which it domes. A thick lateritic cover averages about 150 m in thickness. Drilling has shown the core to consist of carbonatite, pyroxenite, dunite and peridotite.
Salitre comprises two interconnected intrusions cutting low grade metamorphic rocks of the Precambrian Bambui Group, which are domed around the intrusions. The smaller northwestern intrusion covers 15 km2 and is connected by trachytic outcrops to a southeastern complex of some 35 km2.
A suite of pebbles and cobbles of carbonatite and alkaline rocks, including pulaskite, urtite, melteigite and alkali gabbro, occur within conglomerates of the Cretaceous Uberaba Formation. They are thought to derive from an unknown intrusion, not those lying to the west, i.e.