Bairro Da Cruz
An oval-shaped complex of about 1 km diameter. Olivine gabbro and phonolite are present but little information is available.
Complete list of alkaline rocks and carbonatites
An oval-shaped complex of about 1 km diameter. Olivine gabbro and phonolite are present but little information is available.
The complex of Jacupiranga is an oval-shaped intrusion of 65 km2 emplaced in mica schists and granodiorites of the Precambrian Acungui Group, which are fenitized and nephelinized in places.
A stock of less than 1 km2 forms the hill of Sao Joao and is surrounded by Recent sediments which obscure the contacts. The principal rocks are biotite pulaskite and nordmarkite, the latter containing quartz; both rock types include amphibole and a diopsidic pyroxene.
A circular dome 11 km wide with annular and radial fractures is thought to lie above an alkaline intrusion. Dykes, which may have been alkaline, are heavily weathered.
Within the Lages dome, which is some 30 km in diameter, numerous alkaline intrusions are emplaced, mainly within Permo-Carboniferous sandstones. The majority of the intrusions are sheet-like in form but dykes up to several 100s of metres in thickness also occur.
Anitapolis is a partially zoned intrusion of 5 km2, the emplacement of which produced a system of radial and concentric fractures in the surrounding Precambrian granites.
This is a small occurrence of syenite which contains aegirine-augite and is surrounded by Quaternary sediments.
This is a province of over 30 pipes, up to 500 metres in diameter, which extends over a northwest-trending area of 20x5 km along the Arroio Moirao Graben. Most of the pipes intrude red beds of the Caneleiras Formation, are related to fractures and occur in clusters of two or more.
This is a dome approximately 6 km in diameter, similar to Vargeao (025-00-111), beneath which may lie an alkaline complex.
This complex comprises a series of intrusions and associated volcanics forming a northwest-southeast-trending line over some 10 km. There are four distinct intrusions of peridotite with dunitic cores.