3D Geophysical and Geological Modeling of the South Orkney Microcontinent (Antarctica): Tectonic Implications for the Scotia Arc Development

• Published in: Tectonics
• Main Authors: Morales-Ocaña, Cecilia, Bohoyo, Fernando, Escutia, Carlota, Marín-Lechado, C., Rey Moral, María del Carmen, Druet Vélez, María, Galindo-Zaldívar, Jesús, Maestro González, Adolfo
• Other Authors: Ministerio de Ciencia, Innovación y Universidades (España), European Commission
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons 2023
• Subjects: Antarctic; Antarctic Peninsula; Pacific; Powell Basin; The Antarctic; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10261/339165; https://doi.org/10.1029/2022TC007602

[EN] The opening of the Scotia Arc resulted in the final breakup of the land bridge between South America and the Antarctic Peninsula. The South Orkney Microcontinent (SOM) constituted part of this former connection and it is now the largest continental block in the Southern Scotia Arc. We present the first 3D model of the SOM that, given its strategic position and characteristics, allows us to advance the knowledge of the tectonic processes involved in the development of the Scotia Arc. Due to the scarcity of reliable geological data, the initial approximation of the deep structure of the SOM was supported by the calculation of three main geological boundaries from geophysical data: the acoustic basement, the boundary of the magnetic anomaly source and the Moho depth. The 3D model was built, refined and validated by forward modeling and joint inversion of gravity and magnetic data. We have accurately defined the geometry of the sedimentary cover, determined the geometry of the intrusive igneous body causing the Pacific Margin Anomaly (PMA) and mapped the heterogeneity of the crustal thickness. These structural features show a clear relationship to each other and are consistent with an important E-W extension to the east of the SOM during early stages of the Scotia Arc formation, prior to the opening of the Powell Basin. This research was funded by the Spanish Ministry of Science, Innovation and Universities predoctoral Grant PRE2018-084612 linked to the coordinated project TASDRACC (CTM2017-89711-C2-1P and CTM2017-89711-C2-2P), cofounded by the European Union through FEDER funds. Peer reviewed