Produção Nacional
Potencial para placeres mineralizados em zircão rico em háfnio na região de Cananéia, estado de São Paulo
2005; Sociedade Brasileira de Geologia; Volume: 35; Issue: 4 Linguagem: Inglês
10.5327/rbg.v35i4.1200
ISSN2317-4889
AutoresRonaldo Mello Pereira, Rafael Bastos da Silva, Marcelo Fagundes de Rezende, Ciro Alexandre Ávila, Reiner Neumann,
Tópico(s)Geological formations and processes
ResumoThe aim of this paper is to present the results of a heavy pan research in the Cananeia region. This area has alluvial and marine deposits close to the Itapitangui range formed by a neoproterozoic granite (Mandira granitoid), an A-type body, peralkaline, with a Hf-rich zircon (9% to 12% HfO 2 and atomic ratio 100 . Hf / (Hf + Zr) between 8.5 to 11.9 mol. % HfSiO 4 ). Zircon, in bipyramidal form, is present in the stream sediments of the creeks and rivers and has a concentration near 1.3 kg/m 3 . The sources of this zircon are the riebeckite alkali-granite of the Mandira Granitoid with 0.900 kg/t of zircon; the Neogene monomitic fanglomerate with zircon in the granitic blocks, pebbles and in the sandy matrix; the talus deposits with zircon associated to the clay-sand matrix; and the upper layers of gravels of the alluvial flats. The concentration of the Hf-rich zircon ranges between 0.650 kg/m 3 to 1.4 kg/m 3 in the gravel deposits of the creeks and 10.0 kg/m 3 in the gravels deposits of the Itapitangui river. The results point to an economic concentration of the Hf-rich zircon in the alluvial flats gravel’s and, perhaps, in some marine deposits of the Cananeia area.
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