Fracturing and healing of basaltic magmas during explosive volcanic eruptions
Por:
Taddeucci, J., Cimarelli, C., Alatorre-Ibarguengoitia, M. A., Delgado-Granados, H., Andronico, D., Del Bello, E., Scarlato, P., Di Stefano, F.
Publicada:
1 abr 2021
Ahead of Print:
1 mar 2021
Categoría:
Earth and planetary sciences (miscellaneous)
Resumen:
The eruption of basaltic magmas dominates explosive volcanism on Earth
and other planets within the Solar System. The mechanism through which
continuous magma fragments into volcanic particles is central in
governing eruption dynamics and the ensuing hazards. However, the
mechanism of fragmentation of basaltic magmas is still disputed, with
both viscous and brittle mechanisms having been proposed. Here we carry
out textural analysis of the products of ten eruptions from seven
volcanoes by scanning electron microscopy. We find broken crystals
surrounded by intact glass that testify to the brittle fragmentation of
basaltic magmas during explosive activity worldwide. We then replicated
the natural textures of broken crystals in laboratory experiments where
variably crystallized basaltic melt was fragmented by rapid deformation.
The experiments reveal that crystals are broken by the propagation of a
network of fractures through magma, and that afterwards the fractures
heal by viscous flow of the melt. Fracturing and healing affect gas
mobility, stress distribution, and bubble and crystal size distributions
in magma. Our results challenge the idea that the grain size
distribution of basaltic eruption products reflects the density of
fractures that initially fragmented the magma and ultimately indicate
that brittle fracturing and viscous healing of magma may underlie
basaltic explosive eruptions globally.
Filiaciones:
Taddeucci, J.:
(Corresponding Author), Ist Nazl Geofis & Vulcanol, Sez Roma1, Rome, Italy
Ist Nazl Geofis & Vulcanol, Sez Roma1, Rome, Italy
Cimarelli, C.:
Ludwig Maximilians Univ Munchen, Dept Earth & Environm Sci, Munich, Germany
Alatorre-Ibarguengoitia, M. A.:
Univ Ciencias & Artes Chiapas, Inst Invest Gest Riesgo & Cambio Climat, Tuxtla, Mexico
Delgado-Granados, H.:
Univ Nacl Autonoma Mexico Circuito Exterior, Inst Geofis, Dept Vulcanol, Mexico City, DF, Mexico
Andronico, D.:
Ist Nazl Geofis & Vulcanol, Osservatorio Etneo Sez Catania, Catania, Italy
Del Bello, E.:
Ist Nazl Geofis & Vulcanol, Sez Roma1, Rome, Italy
Scarlato, P.:
Ist Nazl Geofis & Vulcanol, Sez Roma1, Rome, Italy
Di Stefano, F.:
Ist Nazl Geofis & Vulcanol, Sez Roma1, Rome, Italy
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