Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies

The Plio-Pleistocene Llancanelo volcanic field is located in the south-eastern region of the province of Mendoza, Argentina. This wide back-arc lava plateau, with hundreds of monogenetic pyroclastic cones, covers a large area behind the active Andean volcanic arc. Here we focus on the northern Llanc...

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Autores principales: Prezzi, C., Risso, C., Orgeira, M.J., Nullo, F., Sigismondi, M.E., Margonari, L.
Formato: JOUR
Materias:
Gravity modeling
Llancanelo volcanic field, Argentina
Magnetic anomaly
Sub-surface structure
Bouguer anomaly
cinder cone
flow field
geophysical method
island arc
lava flow
paleomagnetism
pyroclastic flow
Argentina
Mendoza
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_08959811_v77_n_p247_Prezzi
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_08959811_v77_n_p247_Prezzi2023-10-03T15:43:29Z Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies Prezzi, C. Risso, C. Orgeira, M.J. Nullo, F. Sigismondi, M.E. Margonari, L. Gravity modeling Llancanelo volcanic field, Argentina Magnetic anomaly Sub-surface structure Bouguer anomaly cinder cone flow field geophysical method island arc lava flow paleomagnetism pyroclastic flow Argentina Mendoza The Plio-Pleistocene Llancanelo volcanic field is located in the south-eastern region of the province of Mendoza, Argentina. This wide back-arc lava plateau, with hundreds of monogenetic pyroclastic cones, covers a large area behind the active Andean volcanic arc. Here we focus on the northern Llancanelo volcanic field, particularly in Las Bombas volcano. Las Bombas volcano is an eroded, but still recognizable, scoria cone located in a circular depression surrounded by a basaltic lava flow, suggesting that Las Bombas volcano was there when the lava flow field formed and, therefore, the lava flow engulfed it completely. While this explanation seems reasonable, the common presence of similar landforms in this part of the field justifies the need to establish correctly the stratigraphic relationship between lava flow fields and these circular depressions. The main purpose of this research is to investigate Las Bombas volcano 3D subsurface architecture by means of geophysical methods. We carried out a paleomagnetic study and detailed topographic, magnetic and gravimetric land surveys. Magnetic anomalies of normal and reverse polarity and paleomagnetic results point to the occurrence of two different volcanic episodes. A circular low Bouguer anomaly was detected beneath Las Bombas scoria cone indicating the existence of a mass deficit. A 3D forward gravity model was constructed, which suggests that the mass deficit would be related to the presence of fracture zones below Las Bombas volcano cone, due to sudden degassing of younger magma beneath it, or to a single phreatomagmatic explosion. Our results provide new and detailed information about Las Bombas volcano subsurface architecture. © 2017 Elsevier Ltd JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_08959811_v77_n_p247_Prezzi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Gravity modeling
Llancanelo volcanic field, Argentina
Magnetic anomaly
Sub-surface structure
Bouguer anomaly
cinder cone
flow field
geophysical method
island arc
lava flow
paleomagnetism
pyroclastic flow
Argentina
Mendoza
spellingShingle Gravity modeling
Llancanelo volcanic field, Argentina
Magnetic anomaly
Sub-surface structure
Bouguer anomaly
cinder cone
flow field
geophysical method
island arc
lava flow
paleomagnetism
pyroclastic flow
Argentina
Mendoza
Prezzi, C.
Risso, C.
Orgeira, M.J.
Nullo, F.
Sigismondi, M.E.
Margonari, L.
Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies
topic_facet Gravity modeling
Llancanelo volcanic field, Argentina
Magnetic anomaly
Sub-surface structure
Bouguer anomaly
cinder cone
flow field
geophysical method
island arc
lava flow
paleomagnetism
pyroclastic flow
Argentina
Mendoza
description The Plio-Pleistocene Llancanelo volcanic field is located in the south-eastern region of the province of Mendoza, Argentina. This wide back-arc lava plateau, with hundreds of monogenetic pyroclastic cones, covers a large area behind the active Andean volcanic arc. Here we focus on the northern Llancanelo volcanic field, particularly in Las Bombas volcano. Las Bombas volcano is an eroded, but still recognizable, scoria cone located in a circular depression surrounded by a basaltic lava flow, suggesting that Las Bombas volcano was there when the lava flow field formed and, therefore, the lava flow engulfed it completely. While this explanation seems reasonable, the common presence of similar landforms in this part of the field justifies the need to establish correctly the stratigraphic relationship between lava flow fields and these circular depressions. The main purpose of this research is to investigate Las Bombas volcano 3D subsurface architecture by means of geophysical methods. We carried out a paleomagnetic study and detailed topographic, magnetic and gravimetric land surveys. Magnetic anomalies of normal and reverse polarity and paleomagnetic results point to the occurrence of two different volcanic episodes. A circular low Bouguer anomaly was detected beneath Las Bombas scoria cone indicating the existence of a mass deficit. A 3D forward gravity model was constructed, which suggests that the mass deficit would be related to the presence of fracture zones below Las Bombas volcano cone, due to sudden degassing of younger magma beneath it, or to a single phreatomagmatic explosion. Our results provide new and detailed information about Las Bombas volcano subsurface architecture. © 2017 Elsevier Ltd
format JOUR
author Prezzi, C.
Risso, C.
Orgeira, M.J.
Nullo, F.
Sigismondi, M.E.
Margonari, L.
author_facet Prezzi, C.
Risso, C.
Orgeira, M.J.
Nullo, F.
Sigismondi, M.E.
Margonari, L.
author_sort Prezzi, C.
title Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies
title_short Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies
title_full Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies
title_fullStr Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies
title_full_unstemmed Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies
title_sort subsurface architecture of las bombas volcano circular structure (southern mendoza, argentina) from geophysical studies
url http://hdl.handle.net/20.500.12110/paper_08959811_v77_n_p247_Prezzi
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