Tectonic activity evolution of the Scotia-Antarctic Plate boundary from mass transport deposit analysis

• Published in: Journal of Geophysical Research: Solid Earth
• Main Authors: Pérez, Lara F., Bohoyo Muñoz, Fernando, Hernández Molina, Francisco Javier, Casas Layola, David, Galindo Zaldívar, Jesús, Ruano, Patricia, Maldonado, Andrés
• Format: Other/Unknown Material
• Language: English
• Published: American Geophysical Union 2020
• Subjects: Placa Antártica; Oligoceno; Plioceno; tectónica; Mar de Scotia; Antarctic; The Antarctic; Scotia Sea; Shackleton; Greenland; Holloway; East Scotia Ridge; Shackleton Fracture Zone; West Scotia Ridge; Antarc*; Antártica
• Online Access: https://hdl.handle.net/20.500.12468/372; https://doi.org/10.1002/2015JB012622

The spatial distribution and temporal occurrence of mass transport deposits (MTDs) in the sedimentary infill of basins and submerged banks near the Scotia-Antarctic plate boundary allowed us to decode the evolution of the tectonic activity of the relevant structures in the region from the Oligocene to present day. The 1020 MTDs identified in the available data set of multichannel seismic reflection profiles in the region are subdivided according to the geographic and chronological distributions of these features. Their spatial distribution reveals a preferential location along the eastern margins of the eastern basins. This reflects local deformation due to the evolution of the Scotia-Antarctic transcurrent plate boundary and the impact of oceanic spreading along the East Scotia Ridge (ESR). The vertical distribution of the MTDs in the sedimentary record evidences intensified regional tectonic deformation from the middle Miocene to Quaternary. Intensified deformation started at about 15 Ma, when the ESR progressively replaces the West Scotia Ridge (WSR) as the main oceanic spreading center in the Scotia Sea. Coevally with the WSR demise at about 6.5 Ma, increased spreading rates of the ESR and numerous MTDs were formed. The high frequency of MTDs during the Pliocene, mainly along the western basins, is also related to greater tectonic activity due to uplift of the Shackleton Fracture Zone by tectonic inversion and extinction of the Antarctic-Phoenix Ridge and involved changes at late Pliocene. The presence of MTDs in the southern Scotia Sea basins is a relevant indicator of the interplay between sedimentary instability and regional tectonics. Geophysical Department, Geological Survey of Denmark and Greenland, Dinamarca Instituto Geológico y Minero de España, España Department of Earth Sciences, Royal Holloway University of London, Reino Unido Instituto Andaluz de Ciencias de la Tierra, Universidad de Granada, España Instituto Andaluz de Ciencias de la Tierra, Consejo Superior de Investigaciones ...