@article{fdi:010062513,
  title = {{T}he 3640-3510 {BC} rhyodacite eruption of {C}hachimbiro compound volcano, {E}cuador : a violent directed blast produced by a satellite dome},
  author = {{B}ernard, {B}. and {H}idalgo, {S}. and {R}obin, {C}laude and {B}eate, {B}. and {Q}uijozaca, {J}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ased on geochronological, petrological, stratigraphical, and sedimentological data, this paper describes the deposits left by the most powerful {H}olocene eruption of {C}hachimbiro compound volcano, in the northern part of {E}cuador. {T}he eruption, dated between 3640 and 3510 years {BC}, extruded a similar to 650-m-wide and similar to 225-m-high rhyodacite dome, located 6.3 km east of the central vent, that exploded and produced a large pyroclastic density current ({PDC}) directed to the southeast followed by a sub-{P}linian eruptive column drifted by the wind to the west. {T}he {PDC} deposit comprises two main layers. {T}he lower layer ({L}1) is massive, typically coarse-grained and fines-depleted, with abundant dense juvenile fragments from the outgassed dome crust. {T}he upper layer ({L}2) consists of stratified coarse ash and lapilli laminae, with juvenile clasts showing a wide density range (0.7-2.6 g cm(-3)). {T}he thickness of the whole deposit ranges from few decimeters on the hills to several meters in the valleys. {D}eposits extending across six valleys perpendicular to the flow direction allowed us to determine a minimum velocity of 120 m s(-1). {T}hese characteristics show striking similarities with deposits of high-energy turbulent stratified currents and in particular directed blasts. {T}he explosion destroyed most of the dome built during the eruption. {S}ubsequently, the sub-{P}linian phase left a decimeter-thick accidental-fragment-rich pumice layer in the {C}hachimbiro highlands. {J}uvenile clasts, rhyodacitic in composition ({S}i{O}2 = 68.3 wt%), represent the most differentiated magma of {C}hachimbiro volcano. {M}agma processes occurred at two different depths (similar to 14.4 and 8.0 km). {T}he hot (similar to 936 degrees {C}) deep reservoir fed the central vent while the shallow reservoir (similar to 858 degrees {C}) had an independent evolution, probably controlled by {E}l {A}ngel regional fault system. {S}uch destructive eruptions, related to peripheral domes, are of critical importance for hazard assessment in large silicic volcanic complexes such as those forming the {F}rontal {V}olcanic {A}rc of {E}cuador and {C}olombia.},
  keywords = {{C}hachimbiro ; {R}yodacite ; {D}irected blast ; {S}atellite dome ; {P}hysical ; volcanology ; {T}hermobarometry ; {EQUATEUR}},
  booktitle = {},
  journal = {{B}ulletin of {V}olcanology},
  volume = {76},
  numero = {9},
  pages = {art. 849 [20 ]},
  ISSN = {0258-8900},
  year = {2014},
  DOI = {10.1007/s00445-014-0849-z},
  URL = {https://www.documentation.ird.fr/hor/fdi:010062513},
}