CO2 fluid inclusion barometry in mantle xenoliths from central Mexico: A detailed record of magma ascent
Por:
Levresse, Gilles, Elizabeth Cervantes-de la Cruz, Karina, Jorge Aranda-Gomez, Jose, Guadalupe Davalos-Elizondo, Maria, Jimenez-Sandoval, Sergio, Rodriguez-Melgarejo, Francisco, Araceli Alba-Aldave, Leticia
Publicada:
15 ene 2016
Resumen:
Chemical equilibrium and CO2 fluid inclusion barometry are complementary
techniques, as they register different geological processes. Chemical
equilibrium barometry records the pressure at the site where the
xenoliths were incorporated into the transporting magma, but it is not a
sensible technique to document magma ascent. CO2 fluid inclusion pore
pressure in xenoliths does not register the P-T conditions in the source
area, but it allows illustrating a fairly detailed record of different
geological processes that occurred during the magma transport to the
surface and as the eruption proceeded. Mantle xenoliths from
Ventura-Espiritu Santo and Santo Domingo volcanic fields contain
dominant CO2 pseudosecondary and secondary fluid inclusions trapped in
cpx and ol. Cpx chemical equilibrium pressures indicate a maximum
pressure of 10 kbar for the source area. Pore pressures obtained in CO2
pseudosecondary and secondary fluid inclusions show a distribution with
three maximum peaks at ca. 8, 5-7, and less than 3 kbar. A comparison
with geophysical models for the area where the xenoliths bearing
volcanoes are located shows that the three peaks in the pore pressures
correspond to three physicochemical transitions within the continental
crust. Likewise, the pore pressure suggests that rapid magma ascent is
momentarily interrupted by these discontinuities, a fact that allows the
formation of new fluid inclusions and the re-equilibration of some of
the inclusions already present in the primary minerals of the xenoliths.
(C) 2015 Elsevier B.V. All rights reserved.
Filiaciones:
Levresse, Gilles:
CGEO UNAM, Campus Juriquilla, Juriquilla 76320, Queretaro, Mexico
Elizabeth Cervantes-de la Cruz, Karina:
CGEO UNAM, Campus Juriquilla, Juriquilla 76320, Queretaro, Mexico
Jorge Aranda-Gomez, Jose:
CGEO UNAM, Campus Juriquilla, Juriquilla 76320, Queretaro, Mexico
Guadalupe Davalos-Elizondo, Maria:
CGEO UNAM, Campus Juriquilla, Juriquilla 76320, Queretaro, Mexico
Jimenez-Sandoval, Sergio:
IPN, Ctr Invest & Estudios Avanzados, POB 11-798, Queretaro 76001, Mexico
Rodriguez-Melgarejo, Francisco:
IPN, Ctr Invest & Estudios Avanzados, POB 11-798, Queretaro 76001, Mexico
Araceli Alba-Aldave, Leticia:
Univ Nacl Autonoma Mexico, Inst Geol, Mexico City 04510, DF, Mexico
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