Record details

Title
    Contrasting pyrophanite - ilmenite solid-solution compositions from the Conta História Fe-Mn deposit, Quadrilátero Ferrífero, Minas Gerais, Brazil
Statement of responsibility
    A. Raphael Cabral, C.D. Sattler
Author
    Cabral, A. Raphael
    Sattler, C. D.
Language
    anglicky
Source title - serial
    Neues Jahrbuch für Mineralogie. Monatshefte
Vol./nr.
    H. 6
Pages
    p. 271-288
Year
    2001
Notes
    3 obr., 3 fot., 5 tab., 3 s.bibl.
    il.
    Zkr. název ser.: Neu. Jb. Mineral., Mh.
Subject group
    chemismus minerálů
    formace železitá
    geneze ložiska
    ilmenit
    izomorfie
    mangan
    manganolity
    metamorfóza
    prekambrium
    roztok pevný
    rudy Fe
    rudy Mn
    železnohorské krystalinikum
Geographical name
    Brazílie-Minas Gerais
    Chvaletice (Pardubice)
    Conta História (Brazílie-Minas Gerais)
    ČR-Čechy
    Ghana
    Indie
    Nigérie
    Rumunsko
    USA-New Jersey
Keyword
    Brazil
    Compositions
    Conta
    Contrasting
    Deposit
    Fe-Mn
    Ferrífero
    Gerais
    História
    Ilmenite
    Minas
    Pyrophanite
    Quadrilátero
    Solid-solution
Abstract (in english)
   Three compositional groups of the pyrophanite-ilmenite solution (Py-Ilmss) are reported from the Conta História manganese oxide deposit in the Quadrilátero Ferrífero, Minas Gerais, Brazil. One is Mn-rich (ilmenite-bearing pyrophanite), found in the secondary Mn-oxide matrix of the garnet-bearing ore; the other is richer in Fe and occurs as inclusions in completely replaced garnet porphyroblasts. The third one is a manganese oxide matrix-hosted pyrophanite-rich ilmenite from podiform Mn orebodies along fault zones. Ilmenite-series crystals of the first and second groups are contemporaneous and metamorphic-derived; the compositional difference is attributable to distinct Fe-Mn partioning between Py-Ilmss and host mineral. The third group is derived from the interaction of Mn-bearing hydrothermal fluids and a Ti-Fe precursor.
   The presence of these minerals within a weahering-derived Mn-oxide groundmass and pseudomorphs after garnet indicates that the protore was a metamorphosed manganese-rich sediment. The data do not support the proposition of Nayak a Mohapatra (1998) that Mn-rich ilmenite-series members characterise Mn-rich parametamorphites
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    21. 8. 2007
Import date
    8. 8. 2012