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1282293 
Journal Article 
Geoquimica e geologia isotopica (Sm-Nd e U-Pb) do magmatismo traquitico no deposito de estanho do Bom Futuro (RO) 
Souza, VdaS; Botelho, NF; Dantas, EL; Laux, JH 
2007 
0 
Revista Brasileira de Geociencias
ISSN: 0375-7536 
Sociedade Brasileira de Geologia 
Brazil (BRA) 
37 
4 (2007) 
660-667 
The Bom Futuro tin deposit is an important register of the anorogenic neoproterozoic magmatism that occurred in the SW Amazonian Craton region, which was responsible for expressive Sn, W, Nb, Ta, F, topaz and beryl mineralization in the central part of the Rondonian Tin Province. This deposit is formed in the central part by a small plutono-volcanic system composed of a volcanicbreccia pipe, as well as albite granite, rhyolite and trachyte dykes with Sn -ore confined in quartz-topaz veinsveinlets and greisens. The albite granite magmatic phase is closely associated with the hydrothermal phase responsible for postmagmatic reactions and subsequent Sn -ore. However, the age of this magmatic phase is not yet clearly defined, mainly due the pronounced metamict characteristics of zircon crystals. The geochemical and isotopic data presented in this paper demonstrate that albite granite and rhiolite dykes represent a peraluminous, subalkaline and highly fractioned magmatic phase, while the trackyte dykes represent a peraluminous, alkaline and little fractionated magmatic phase. These two magmatic phases show negative values of Nd(t), which are indicative of crustal derivation. The U-Pb age obtained in zircon from the trackyte dikes is 1001 + or - 5.2 Ma, which is interpreted as related to a chrystallization event. Considering the geochronological information on the late to post-magmatic hydrothermal processes responsible for Sn -ore into the veins and greisen systems (969 to 997Ma), which are associated with albite granite magmatism, we conclude that the subalkaline and alkaline magmatic phases are at least contemporary. Although the alkaline trackytic phase represent a magmatic episode unlinked from tin mineralization. 
Bom Futuro Complex; petrology; hydrothermal alteration; absolute age; metallogenic provinces; tin ores; mineral composition; major elements; Bom Futuro Deposit; mineral deposits, genesis; Brazil; pipes; Amazonian Craton; Palanqueta Complex; Precambrian; South America; geochemistry; volcanic rocks; intrusions; plutonic rocks; textures; granites; Rondonia Brazil; Sm/Nd; U/Pb; metasomatism; Neoproterozoic; breccia pipes; A-type granites; metal ores; Proterozoic; Jamari Complex; metallogeny; dates; Rondonia tin province; mineral exploration; trace elements; upper Precambrian; magmatism; alkalic composition; igneous rocks; trachytes