Spatial and Temporal Controls on the Distribution of Indium in Xenothermal Vein-Deposits: The Huari Huari District, Potosi, Bolivia
Por:
Torro, Lisard, Caries Melgarejo, Joan, Gemmrich, Laura, Mollinedo, Diva, Cazorla, Malena, Martinez, Alvaro, Pujol-Sola, Nuria, Farre-de-Pablo, Julia, Camprubi, Antoni, Artiaga, David, Torres, Belen, Alfonso, Pura, Arce, Osvaldo
Publicada:
1 may 2019
Resumen:
The Huari Huari deposit, Potosi Department in SW Bolivia, hosts
polymetallic stratiform and vein mineralization of Miocene age with
significant concentrations of the critical metal indium (In). Vein
mineralization records document early crystallization of quartz and
cassiterite followed by prominent associations of sulfides and
sulfosalts. The earliest sulfide was arsenopyrite, followed by
pyrrhotite, and progressively giving way to pyrite as the main iron
sulfide, whereas Cu-Ag-Pb sulfosalts constitute late hypogene
associations. Sphalerite is the chief ore mineral, and its
crystallization is extended during most of the mineralization lifespan
as evidenced by its initial cocrystallization with pyrrhotine, then with
pyrite, and finally with Ag-Pb sulfosalts. The composition of sphalerite
varies from early to late generations with a continuous decrease in FeS
that attests to a decrease in temperature, which is constrained to vary
from 450 to <200 degrees C, and/or an increase in f(S-2), both congruent
with the described paragenetic sequence. Indium concentrated mostly in
the structure of Fe-rich sphalerite (up to 3.49 wt. %) and stannite (up
to 2.64 wt. %) as limited solid solutions with roquesite in the
(Zn,Fe)S-Cu2FeSnS4-CuInS2 pseudoternary system. In sphalerite, In shows
a strong positive correlation with Cu at Cu/In = 1, suggesting its
incorporation via a (Cu+ + In3+) <-> 2Zn(2+) coupled substitution, and
it does not correlate with Fe. In stannite, In shows a moderate,
negative correlation with Cu and Sn, and an In3+ <-> (Cu+ + 1/2 Sn4+)
coupled substitution is suggested. Coexisting sphalerite and stannite
yielded the highest In concentrations and crystallized at temperatures
between 350 and 250 degrees C. Copper activity probably played a major
role in the accumulation of In in the structure of sphalerite since
In-bearing sphalerite coexisted with the deposition of stannite, shows
high concentrations of Cu (up to 0.13 atoms per formula unit (a.p.f.u.))
in its structure, and hosts exsolutions of stannite and chalcopyrite.
Distribution on the district scale of In suggests an input of
hydrothermal fluids richer in Cu in the central position of the
mineralizing system, represented by the Anton Bravo vein.
Filiaciones:
Torro, Lisard:
Pontifical Catholic Univ Peru PUCP, Fac Sci & Engn, Geol Engn Program, Av Univ 180, Lima 15088, Peru
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Caries Melgarejo, Joan:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Gemmrich, Laura:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Mollinedo, Diva:
Univ Mayor San Andres, Fac Ciencias Geol, Av Villazon 1995,Plaza Bicentenario, La Paz, Bolivia
Cazorla, Malena:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Martinez, Alvaro:
Univ Geneva, Dept Earth Sci, Rue Maraichers 13, CH-1205 Geneva, Switzerland
Pujol-Sola, Nuria:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Farre-de-Pablo, Julia:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Camprubi, Antoni:
Univ Nacl Autonoma Mexico, Inst Geol, Ciudad Univ, Coyoacan 04510, Cdmx, Mexico
Artiaga, David:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Torres, Belen:
Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, C Marti I Franques S-N, E-08028 Barcelona, Spain
Alfonso, Pura:
Univ Politecn Cataluna, Dept Engn Minera Ind & TIC, Av Bases Manresa 61-73, Barcelona 08242, Spain
Arce, Osvaldo:
Colegio Geol Bolivia, Edificio Senor Exaltac 4683, La Paz, Bolivia
Eloro Resources Ltd, Av La Floresta 497,Of 101, Lima, Peru
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