Skip to content

Thermomechanical modeling of the Altiplano-Puna deformation anomaly: Multiparameter insights into magma mush reorganization

Research output: Contribution to journalArticle

Standard

Thermomechanical modeling of the Altiplano-Puna deformation anomaly : Multiparameter insights into magma mush reorganization. / Gottsmann, Joachim; Blundy, Jon; Henderson, Scott; Pritchard, Matthew; Sparks, Stephen.

In: Geosphere, Vol. 13, No. 4, 08.2017, p. 1042-1065.

Research output: Contribution to journalArticle

Harvard

APA

Vancouver

Author

Bibtex

@article{fbadc0f3b31d477f88586f083091280c,
title = "Thermomechanical modeling of the Altiplano-Puna deformation anomaly: Multiparameter insights into magma mush reorganization",
abstract = "A 150 km wide ground deformation anomaly in the Altiplano-Puna Volcanic Complex (APVC), with uplift centered on Uturuncu volcano and peripheral subsidence, alludes to complex subsurface stress changes. In particular, the role of a large, geophysically anomalous and partially molten reservoir (the Altiplano-Puna Magma Body APMB) located ~20 km beneath the deforming surface, is still poorly understood. To explain the observed spatio-temporal ground deformation pattern, we integrate geophysical and petrological data and develop a numerical model that accounts for a mechanically heterogeneous and visco-elastic crust. Best-fit models imply subsurface stress changes due to the episodic reorganization of an interconnected vertically-extended mid-crustal plumbing system composed of the APMB and a domed bulge-and-column structure. Measured gravity-height gradients data point towards low-density fluid migration as the dominant process behind the stress changes. We calculate a mean annual flux of ~2*107 m3 of water-rich andesitic melt and/or magmatic water from the APMB into the bulge-and-column accompanied by modest pressure changes of <0.006 MPa/year. Two configurations of the column fit the observations equally well: i) a magmatic (igneous mush) column that extends to a depth of 6 km b.s.l and contains trapped volatiles or ii) a volatile-bearing hybrid column composed of an igneous mush below a solidified and permeable body that extends to sea level. Volatile loss from the bulge-and-column reverses the deformation, and explains the absence of broad (tens of km) and long-term (>100 years) residual deformation at Uturuncu. Episodic mush reorganization may be an ubiquitous characteristic of the magmatic evolution of the APVC.",
author = "Joachim Gottsmann and Jon Blundy and Scott Henderson and Matthew Pritchard and Stephen Sparks",
year = "2017",
month = "8",
doi = "10.1130/GES01420.1",
language = "English",
volume = "13",
pages = "1042--1065",
journal = "Geosphere",
issn = "1553-040X",
publisher = "Geological Society of America",
number = "4",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Thermomechanical modeling of the Altiplano-Puna deformation anomaly

T2 - Geosphere

AU - Gottsmann, Joachim

AU - Blundy, Jon

AU - Henderson, Scott

AU - Pritchard, Matthew

AU - Sparks, Stephen

PY - 2017/8

Y1 - 2017/8

N2 - A 150 km wide ground deformation anomaly in the Altiplano-Puna Volcanic Complex (APVC), with uplift centered on Uturuncu volcano and peripheral subsidence, alludes to complex subsurface stress changes. In particular, the role of a large, geophysically anomalous and partially molten reservoir (the Altiplano-Puna Magma Body APMB) located ~20 km beneath the deforming surface, is still poorly understood. To explain the observed spatio-temporal ground deformation pattern, we integrate geophysical and petrological data and develop a numerical model that accounts for a mechanically heterogeneous and visco-elastic crust. Best-fit models imply subsurface stress changes due to the episodic reorganization of an interconnected vertically-extended mid-crustal plumbing system composed of the APMB and a domed bulge-and-column structure. Measured gravity-height gradients data point towards low-density fluid migration as the dominant process behind the stress changes. We calculate a mean annual flux of ~2*107 m3 of water-rich andesitic melt and/or magmatic water from the APMB into the bulge-and-column accompanied by modest pressure changes of <0.006 MPa/year. Two configurations of the column fit the observations equally well: i) a magmatic (igneous mush) column that extends to a depth of 6 km b.s.l and contains trapped volatiles or ii) a volatile-bearing hybrid column composed of an igneous mush below a solidified and permeable body that extends to sea level. Volatile loss from the bulge-and-column reverses the deformation, and explains the absence of broad (tens of km) and long-term (>100 years) residual deformation at Uturuncu. Episodic mush reorganization may be an ubiquitous characteristic of the magmatic evolution of the APVC.

AB - A 150 km wide ground deformation anomaly in the Altiplano-Puna Volcanic Complex (APVC), with uplift centered on Uturuncu volcano and peripheral subsidence, alludes to complex subsurface stress changes. In particular, the role of a large, geophysically anomalous and partially molten reservoir (the Altiplano-Puna Magma Body APMB) located ~20 km beneath the deforming surface, is still poorly understood. To explain the observed spatio-temporal ground deformation pattern, we integrate geophysical and petrological data and develop a numerical model that accounts for a mechanically heterogeneous and visco-elastic crust. Best-fit models imply subsurface stress changes due to the episodic reorganization of an interconnected vertically-extended mid-crustal plumbing system composed of the APMB and a domed bulge-and-column structure. Measured gravity-height gradients data point towards low-density fluid migration as the dominant process behind the stress changes. We calculate a mean annual flux of ~2*107 m3 of water-rich andesitic melt and/or magmatic water from the APMB into the bulge-and-column accompanied by modest pressure changes of <0.006 MPa/year. Two configurations of the column fit the observations equally well: i) a magmatic (igneous mush) column that extends to a depth of 6 km b.s.l and contains trapped volatiles or ii) a volatile-bearing hybrid column composed of an igneous mush below a solidified and permeable body that extends to sea level. Volatile loss from the bulge-and-column reverses the deformation, and explains the absence of broad (tens of km) and long-term (>100 years) residual deformation at Uturuncu. Episodic mush reorganization may be an ubiquitous characteristic of the magmatic evolution of the APVC.

U2 - 10.1130/GES01420.1

DO - 10.1130/GES01420.1

M3 - Article

VL - 13

SP - 1042

EP - 1065

JO - Geosphere

JF - Geosphere

SN - 1553-040X

IS - 4

ER -