Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics
Abstract We use 3‐D magnetotellurics to improve our understanding of the structure and magma composition of Newberry Volcano in Oregon, USA. Newberry is a broad shield volcano with a summit caldera and strongly bimodal magmatism. Newberry has long been the subject of geothermal exploration research,...
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| Format: | Article |
| Language: | English |
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Wiley
2020-03-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2019GC008831 |
| _version_ | 1827771688959344640 |
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| author | E. Bowles‐Martinez A. Schultz |
| author_facet | E. Bowles‐Martinez A. Schultz |
| author_sort | E. Bowles‐Martinez |
| collection | DOAJ |
| description | Abstract We use 3‐D magnetotellurics to improve our understanding of the structure and magma composition of Newberry Volcano in Oregon, USA. Newberry is a broad shield volcano with a summit caldera and strongly bimodal magmatism. Newberry has long been the subject of geothermal exploration research, but that work has focused on the volcano's west flank, leaving the caldera largely unstudied with geophysical methods until recently. Our modeling shows a relatively resistive magma reservoir of approximately 50 Ωm. Our work builds upon recent seismic models and petrological analysis to interpret Newberry's magma reservoir as a dry rhyolite with 8–11% partial melt, which matches the seismically determined melt fraction. Finding the conditions within the magma reservoir that allow the resistivity and seismic analysis to come to the same melt fraction helps us narrow down the magma temperature and composition. From this we infer a dry rhyolitic magma at 850 °C. We also image a prominent vertical conductive anomaly along the south rim below the vent that produced the most recent eruption. The anomaly extends from magma reservoir depths of 3 km to 1 km below the surface where it disperses into the caldera fill. We interpret this as the main conduit for magmatic fluids to reach Newberry's hydrothermal system. Other features that our model shows include higher conductivity along the caldera rim and a resistive older pluton on the west flank. |
| first_indexed | 2024-03-11T12:58:46Z |
| format | Article |
| id | doaj.art-a67079f917f6491d8e55621a028a3376 |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:58:46Z |
| publishDate | 2020-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-a67079f917f6491d8e55621a028a33762023-11-03T16:55:58ZengWileyGeochemistry, Geophysics, Geosystems1525-20272020-03-01213n/an/a10.1029/2019GC008831Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From MagnetotelluricsE. Bowles‐Martinez0A. Schultz1College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis OR USACollege of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis OR USAAbstract We use 3‐D magnetotellurics to improve our understanding of the structure and magma composition of Newberry Volcano in Oregon, USA. Newberry is a broad shield volcano with a summit caldera and strongly bimodal magmatism. Newberry has long been the subject of geothermal exploration research, but that work has focused on the volcano's west flank, leaving the caldera largely unstudied with geophysical methods until recently. Our modeling shows a relatively resistive magma reservoir of approximately 50 Ωm. Our work builds upon recent seismic models and petrological analysis to interpret Newberry's magma reservoir as a dry rhyolite with 8–11% partial melt, which matches the seismically determined melt fraction. Finding the conditions within the magma reservoir that allow the resistivity and seismic analysis to come to the same melt fraction helps us narrow down the magma temperature and composition. From this we infer a dry rhyolitic magma at 850 °C. We also image a prominent vertical conductive anomaly along the south rim below the vent that produced the most recent eruption. The anomaly extends from magma reservoir depths of 3 km to 1 km below the surface where it disperses into the caldera fill. We interpret this as the main conduit for magmatic fluids to reach Newberry's hydrothermal system. Other features that our model shows include higher conductivity along the caldera rim and a resistive older pluton on the west flank.https://doi.org/10.1029/2019GC008831calderarhyolitemagnetotelluricshydrothermalNewberryCascades |
| spellingShingle | E. Bowles‐Martinez A. Schultz Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics Geochemistry, Geophysics, Geosystems caldera rhyolite magnetotellurics hydrothermal Newberry Cascades |
| title | Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics |
| title_full | Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics |
| title_fullStr | Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics |
| title_full_unstemmed | Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics |
| title_short | Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics |
| title_sort | composition of magma and characteristics of the hydrothermal system of newberry volcano oregon from magnetotellurics |
| topic | caldera rhyolite magnetotellurics hydrothermal Newberry Cascades |
| url | https://doi.org/10.1029/2019GC008831 |
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