Alkaline Rocks and Carbonatites of the World

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Ilha Da Vitoria

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Occurrence number: 
025-00-092
Country: 
Brazil
Region: 
Sao Paulo
Location: 
Longitude: -45, Latitude: -23.75

This island of less than 2 km2 consists of nepheline syenite, pulaskite and syenite, with or without quartz and with gradational boundaries between them. Modal nepheline increases from east to west and its concentration indicates a submerged nepheline syenite centre 1 km west of the island. Dykes are numerous and varied, including trachytes, with and without nepheline, phonolites, some with sodalite, bostonites and teschenites.

References: 
MOTOKI, A. and GOMES, C.B. 1984. Caracterizacao geologica e petrografica do macico alcalino da Ilha de Vitoria, SP. Anais Congresso Brasileiro de Geologia, 33: 4392-9
Fig. 212 Ilha da Vitoria (after Motoki and Gomes, 1984, Fig. 1).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith