Details
| Original language | English |
|---|---|
| Pages (from-to) | 25-45 |
| Number of pages | 21 |
| Journal | Journal of Volcanology and Geothermal Research |
| Volume | 338 |
| Early online date | 19 Mar 2017 |
| Publication status | Published - 15 May 2017 |
Abstract
The petrology of quaternary andesites and dacites from Lastarria volcano was investigated to reconstruct the magma plumbing and storage conditions beneath the volcano. The mineral phase compositions and whole-rock major and trace element compositions were used to constrain temperature, pressure and possible mechanisms for magma differentiation. The applied thermobarometric models include two-pyroxene thermobarometry, plagioclase-melt thermometry, amphibole composition thermobarometry, and Fe-Ti oxide thermo-oxybarometry. The overall temperature estimation is in the range 840 °C to 1060 °C. Calculated oxygen fugacity ranges between NNO to NNO + 1. Results of the geo-barometric calculations reveal multiple magma storage regions, with a distinct storage level in the uppermost crust (~ 6.5–8 km depth), a broad zone at mid-crustal levels (~ 10–18 km depth), and a likely deeper zone at intermediate to lower crustal levels (> 20 km depth). The highest temperatures in the range 940–1040 °C are recorded in minerals stored in the mid-crustal levels (~ 10–18 km depth). The whole-rock compositions clearly indicate that magma mixing is the main parameter controlling the general differentiation trends. Complex zoning patterns and textures in the plagioclase phenocrysts confirm reheating and remobilization processes due to magma replenishment.
Keywords
- Andesite, Geothermobarometry, Lastarria, Lazufre, Magma mixing, Magma plumbing system, Magmatic differentiation, Pre-eruptive conditions
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Journal of Volcanology and Geothermal Research, Vol. 338, 15.05.2017, p. 25-45.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Decoding magma plumbing and geochemical evolution beneath the Lastarria volcanic complex (Northern Chile)—Evidence for multiple magma storage regions
AU - Stechern, André
AU - Just, Tobias
AU - Holtz, François
AU - Blume-Oeste, Magdalena
AU - Namur, Olivier
N1 - Publisher Copyright: © 2017 Elsevier B.V. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/5/15
Y1 - 2017/5/15
N2 - The petrology of quaternary andesites and dacites from Lastarria volcano was investigated to reconstruct the magma plumbing and storage conditions beneath the volcano. The mineral phase compositions and whole-rock major and trace element compositions were used to constrain temperature, pressure and possible mechanisms for magma differentiation. The applied thermobarometric models include two-pyroxene thermobarometry, plagioclase-melt thermometry, amphibole composition thermobarometry, and Fe-Ti oxide thermo-oxybarometry. The overall temperature estimation is in the range 840 °C to 1060 °C. Calculated oxygen fugacity ranges between NNO to NNO + 1. Results of the geo-barometric calculations reveal multiple magma storage regions, with a distinct storage level in the uppermost crust (~ 6.5–8 km depth), a broad zone at mid-crustal levels (~ 10–18 km depth), and a likely deeper zone at intermediate to lower crustal levels (> 20 km depth). The highest temperatures in the range 940–1040 °C are recorded in minerals stored in the mid-crustal levels (~ 10–18 km depth). The whole-rock compositions clearly indicate that magma mixing is the main parameter controlling the general differentiation trends. Complex zoning patterns and textures in the plagioclase phenocrysts confirm reheating and remobilization processes due to magma replenishment.
AB - The petrology of quaternary andesites and dacites from Lastarria volcano was investigated to reconstruct the magma plumbing and storage conditions beneath the volcano. The mineral phase compositions and whole-rock major and trace element compositions were used to constrain temperature, pressure and possible mechanisms for magma differentiation. The applied thermobarometric models include two-pyroxene thermobarometry, plagioclase-melt thermometry, amphibole composition thermobarometry, and Fe-Ti oxide thermo-oxybarometry. The overall temperature estimation is in the range 840 °C to 1060 °C. Calculated oxygen fugacity ranges between NNO to NNO + 1. Results of the geo-barometric calculations reveal multiple magma storage regions, with a distinct storage level in the uppermost crust (~ 6.5–8 km depth), a broad zone at mid-crustal levels (~ 10–18 km depth), and a likely deeper zone at intermediate to lower crustal levels (> 20 km depth). The highest temperatures in the range 940–1040 °C are recorded in minerals stored in the mid-crustal levels (~ 10–18 km depth). The whole-rock compositions clearly indicate that magma mixing is the main parameter controlling the general differentiation trends. Complex zoning patterns and textures in the plagioclase phenocrysts confirm reheating and remobilization processes due to magma replenishment.
KW - Andesite
KW - Geothermobarometry
KW - Lastarria
KW - Lazufre
KW - Magma mixing
KW - Magma plumbing system
KW - Magmatic differentiation
KW - Pre-eruptive conditions
UR - http://www.scopus.com/inward/record.url?scp=85016425148&partnerID=8YFLogxK
U2 - 10.1016/j.jvolgeores.2017.03.018
DO - 10.1016/j.jvolgeores.2017.03.018
M3 - Article
AN - SCOPUS:85016425148
VL - 338
SP - 25
EP - 45
JO - Journal of Volcanology and Geothermal Research
JF - Journal of Volcanology and Geothermal Research
SN - 0377-0273
ER -