Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Ponte Nova

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Occurrence number: 
025-00-126
Country: 
Brazil
Region: 
Sao Paulo
Location: 
Longitude: -45.75, Latitude: -22.78333
Carbonatite: 
No

Ponte Nova is an alkaline mafic-ultramafic massif belonging to the Serro do Mar Alkaline Province of the southern-central portion of the Brazilian Platform. It consists of a central intrusion and three satellite intrusions to the north, east, and south emplaced into the metasyenogranites, metamonzogranites, and biotite gneisses of the Serra da Água Limpa Batholith. A larger elliptical body (~5.5 km2) represents the main intrusion and the northern and eastern satellites, with an irregular shaped smaller satellite intrusion (~1 km2) 2-3 km to the south. The main intrusion consists mostly of clinopyroxenite cumulates, and nepheline-normative monzogabbro, and monzodiorite cumulates. More evolved compositions occur in the satellite intrusions, with nepheline and nepheline-bearing monzodiorites in the eastern satellite and nepheline-bearing melamonzonites and minor nepheline-bearing monzonites in the southern satellite. A number of small-scale dykes of variable alkaline lithologies (lamprophyre, basanite, tephrite, tephriphonolite, phonotephrites) intrude both the plutonic and country rock. Whole rock geochemical data, petrography, and Sr isotope data for plagioclase and apatite can be found in Azzone et al. (2016), and compositional data for zirconolite, baddeleyite, and Ba-rich feldspar are found in Azzone et al. (2009b).

Age: 
87.6 Ma K/Ar (Azzone et al. 2009a)
References: 
AZZONE, R.G., RUBERTI, G.E.R. & GOMES, C.B., 2009a. Geologia e geocronologia do maciço alcalino máfico-ultramáfico Ponte Nova (SP-MG). Geologia USP - Série Científica 9 pp 23-46. AZZONE, R.G., RUBERTI, E., ENRICH, G.E.R. & GOMES, C.B., 2009. Zr- And Ba-rich minerals from the Ponte Nova alkaline mafic-ultramafic massif, Southeastern Brazil: indication of an enriched mantle source. The Canadian Mineralogist 45 (5) pp 1087-1103. AZZONE, R.G., MUNOZ, P.M., ENRICH, G.E.R., ALVES, A., RUBERTI, E. & GOMES, C.B., 2016. Petrographic, geochemical and isotopic evidence of crustal assimilation processes in the Ponte Nova alkaline mafic–ultramafic massif, SE Brazil. Lithos 260 pp 58-75
Map: 
Fig 1. Ponte Nova (Azzone 2009b, Fig 2.)
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith