PETROLOGIA E METALOGENIA DO MACIÇO PALANQUETA, MINA DE ESTANHO BOM FUTURO, RONDÔNIA, BRASIL: I - GEOLOGIA, PETROGRAFIA E GEOCRONOLOGIA
Petrology and metallogeny of the Palanqueta Massif, Bom Futuro tin mine, Rondônia, Brazil: I - geology, petrography, and geochronology
DOI:
https://doi.org/10.5016/geociencias.v43i3.18546Abstract
The Palanqueta massif occurs in the Rondônia Intrusive Suite (1026-974 Ma) domain in the Rondônia tin province (SW Amazonian Craton). The massif represents a multiphase pluton intruded in a high crustal level. Geologic mapping on 1:2000 scale defined five granitic igneous units, that are represented by one equigranular biotite alkali-feldspar granite (ca. 1026 Ma) and four Li-Fe mica- and topaz-bearing alkali-feldspar granites (ca. 1000 Ma), which are distinguished by structural or textural aspects (inequigranular, porphyritic I, porphyritic II and miarolitic). The Li-Fe mica- and topaz-bearing granites show textural and mineralogical characteristics of peraluminous rare-metal granites. Mineralized greisen bodies (pipes and veins) in rare metals (Sn and W) and base metal (Cu, Pb e Zn) are mainly associated with porphyritic Li-mica- and topaz-bearing alkali-feldspar granite II.