Complex Nb-Ta-Ti-Sn Oxide Mineral Intergrowths In The La Calandria Pegmatite, Cañada Del Puerto, Córdoba, Argentina

• DOI: 10.3749/canmin.1500095
• Publication Date: 2017-05-26T18:05:21Z
• Authors: Miguel Ángel Gall...; María Florencia M...; Petr Černý; Raúl Lira
• Keywords: Columbite; Pegmatite; Cassiterite; Rutile; Metamictization; Metasomatism

The assemblage of Nb-Ta-Ti-Sn oxide minerals in some zoned Devonian granitic pegmatites at the La Calandria mine, Cañada del Puerto, shows complex intergrowths achalaite, ferrotitanowodginite, Ta-rich rutile, columbite-(Mn), ixiolite, and fluorcalciomicrolite.The chemical composition these phases is variable, but general show slight predominance Nb over Ta a clearly defined Fe Mn, with minor participation Ti, Sn, W. this are not equilibrium represent magmatic subsolidus that distinguished texturally chemically.The primary stage mineralization possibly crystallized ixiolite þ rutile I outer zones pegmatite and, less commonly, local columbite-(Mn) inner part.Subsolidus unmixing produced achalaite ferrotitanowodginite II.Contemporaneously, locally exsolved ferrotitanowodginite/achalaite II cassiterite.A localized Ca-F-rich hydrothermal overprinting event transformed to III fluorcalciomicrolite. Furthermore, overprint peripheral transformation widespread distribution fluorcalciomicrolite throughout assemblage.