INVESTIGADORES
HERNANDO Irene Raquel
congresos y reuniones científicas
Título:
The caldera of Payún Matrú volcano, southeastern Mendoza province, Argentina, a result of magma mixing
Autor/es:
LLAMBÍAS, EDUARDO JORGE; HERNANDO, IRENE RAQUEL
Lugar:
Malargue, Mendoza
Reunión:
Simposio; ICES (International Center for Earth Sciences); 2005
Institución organizadora:
CNEA
Resumen:
Payún Matrú is a Pleistocene volcano located in southeastern Mendoza province
(36°25S, 69°12W). It is a typical volcanic dome crowned by a small caldera with a diameter
of 8 km. At its base the diameter is 16 km and its summit rises 1.5 km above the ground level.
With a mainly trachytic composition, it consists of (1) a large pre-caldera volcanic dome, (2)
trachybasaltic to trachytic ignimbrites related to caldera collapse and (3) post-caldera lava flows
in which trachyte dominates over trachybasalt. The volcano is surrounded by a large number of
monogenic cones and lava flows, all of them of olvine basalt composition. Their occurrence, as
both pre- and post-caldera eruptions, indicates that they were contemporaneous with the
evolution of Payún Matrú volcano. Most of the cones are arranged along E-W La Carbonilla
fault that cuts the volcano through its center (Figure 1). However, basaltic cones are absent
within the area of the caldera, presumably because of the basaltic magma having been trapped
into the trachytic magma chamber. In relation to this, the composition of both the caldera
collapse ignimbrites and the first lava flows erupted through the ring fractures are intermediate
between basalt and trachyte, which support the hypothesis of magma mixing.