Análisis de actividad volcánica e hidrotermal submarina reciente en el monte Orca, Rift de Bransfield, Antártica, 62° S 58° o, a través de la interpretación de datos acústicos
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2021
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Esta investigación está enfocada en el volcán submarino Monte Orca,
ubicado en una cuenca de rift de tras-arco en la Antártica Occidental, el Estrecho
de Bransfield, entre las Islas Shetland del Sur y la Península Antártica, la cual
comenzó su abertura hace ~4 Ma debido al cese de la subducción activa de la
Placa de Phoenix por debajo de la Placa Antártica, generando la combinación del
roll-back del slab y movimientos transtensionales entre las placas Antártica y
Scotia con la posterior extensión del tras-arco y una fase de intenso magmatismo,
formando volcanes submarinos y centros eruptivos en el eje axial del rift con
actividad volcánica e hidrotermal asociada. En la actualidad se cree que el rift se
encuentra inactivo o en una fase de muy baja actividad, sin embargo, variados
estudios han encontrado evidencia volcánica e hidrotermal reciente en la cuenca,
sugiriendo un estado de rifting activo o posible expansión de fondo marino. Este
estudio se basa en precisar actividad volcánica e hidrotermal submarina reciente,
mediante el análisis e interpretación de datos acústicos para la resolución del
estado activo de la cuenca y el avance en la comprensión de los fenómenos
geodinámicos de la región. En el año 2019 se llevó a cabo la Campaña de
Expedición Científica ANTAR XXVI en el buque Peruano B.A.P. Carrasco (BOP-
171) en donde se realizó un levantamiento batimétrico a través de la adquisición
de datos acústicos por la ecosonda multihaz Kongsberg EM-122 y el Perfilador
Sísmico de Sub-fondo SBP 120. Los datos post-procesados fueron ordenados en
una grilla de alta resolución del fondo marino como una superficie dinámica con
diversos valores de backscatter para las capas superficiales, probando la
existencia de morfologías y estructuras volcano-hidrotermales con acumulación
de magma en zonas superficiales del fondo marino como centros volcánicos
lineales, flujos de lava, estructuras de colapso y fumarolas hidrotermales
emplazadas en fisuras eruptivas a lo largo del eje axial del rift con orientaciones
SW-NE. En base a estos indicios se precisó la evidencia de actividad volcánica
e hidrotermal reciente, dilucidando el estado activo de rifting de la cuenca,
aportando en la comprensión de los fenómenos geodinámicos de la región.
This research it is focused on the submarine volcano Monte Orca, located in an back-arc rift basin in the Western Antarctica, the Bransfield Strait, between the South Shetland Islands and the Antarctic Peninsula, which began its opening about ~4 Ma ago due to cessation of the subduction of the Phoenix Plate below the Antarctic Plate, generating the combination of the slab roll-back and transtensional motions between the Antarctic and Scotia plates with the subsequent back-arc extension with a phase of intense magmatism giving way to the formation of underwater volcanoes and eruptive centers in the rift axis with volcanic and hydrothermal associated activity. At the present it is believed that the rift isn’t active or is in a slightly active phase, however, several studies have found recent volcanic and hydrothermal evidence in the basin, suggesting that an active state of rifting or maybe seafloor spreading could be continuing along the basin. This study it’s focused on specifying recent submarine volcanic and hydrothermal activity, through the analysis and interpretation of acoustic data for the resolve of the active state of the basin and the progress in the understanding of the geodynamic phenomena of the region. In 2019, the Peruvian vessel B.A.P. Carrasco (BOP-171) started the ANTAR XXVI Scientific Expedition Campaign where a bathymetric survey was carried out through the acquisition of acoustic data by the Kongsberg EM-122 multibeam echo sounder and the SBP 120 Subbottom Seismic Profiler. Post-processed data were arranged in a high-resolution grid as a dynamic surface of the seafloor with various backscatter values for the shallow layers, proving the existence of volcanic and hydrothermal structures and morphologies with magma accumulation at shallow depths of the seabed such as linear volcanic centers, lava flows, collapse structures and hydrothermal vents located in eruptive fissures along the axial axis of the rift with SW-NE orientations. Based on these indications, the evidence of recent volcanic and hydrothermal activity was specified, elucidating the active rifting state of the basin, contributing to the understanding of the geodynamic phenomena of the region.
This research it is focused on the submarine volcano Monte Orca, located in an back-arc rift basin in the Western Antarctica, the Bransfield Strait, between the South Shetland Islands and the Antarctic Peninsula, which began its opening about ~4 Ma ago due to cessation of the subduction of the Phoenix Plate below the Antarctic Plate, generating the combination of the slab roll-back and transtensional motions between the Antarctic and Scotia plates with the subsequent back-arc extension with a phase of intense magmatism giving way to the formation of underwater volcanoes and eruptive centers in the rift axis with volcanic and hydrothermal associated activity. At the present it is believed that the rift isn’t active or is in a slightly active phase, however, several studies have found recent volcanic and hydrothermal evidence in the basin, suggesting that an active state of rifting or maybe seafloor spreading could be continuing along the basin. This study it’s focused on specifying recent submarine volcanic and hydrothermal activity, through the analysis and interpretation of acoustic data for the resolve of the active state of the basin and the progress in the understanding of the geodynamic phenomena of the region. In 2019, the Peruvian vessel B.A.P. Carrasco (BOP-171) started the ANTAR XXVI Scientific Expedition Campaign where a bathymetric survey was carried out through the acquisition of acoustic data by the Kongsberg EM-122 multibeam echo sounder and the SBP 120 Subbottom Seismic Profiler. Post-processed data were arranged in a high-resolution grid as a dynamic surface of the seafloor with various backscatter values for the shallow layers, proving the existence of volcanic and hydrothermal structures and morphologies with magma accumulation at shallow depths of the seabed such as linear volcanic centers, lava flows, collapse structures and hydrothermal vents located in eruptive fissures along the axial axis of the rift with SW-NE orientations. Based on these indications, the evidence of recent volcanic and hydrothermal activity was specified, elucidating the active rifting state of the basin, contributing to the understanding of the geodynamic phenomena of the region.
Notas
Tesis (Geólogo)
Palabras clave
Erupciones Volcánicas, Geología Estructural, Antártica Chilena, Aguas Subterráneas, Sedimentos Marinos, Morfología (Biología)