The transition from an active to a passive margin (SW end of the South Shetland Trench, Antarctic Peninsula)

• Published in: Tectonophysics
• Main Authors: Jabaloy, Antonio, Balanyá, Juan Carlos, Barnolas, Antonio, Galindo Zaldívar, Jesús, Hernández-Molina, Francisco J., Maldonado, Andrés, Martínez-Martínez, José Miguel, Rodríguez-Fernández, José, Sanz de Galdeano, Carlos, Somoza, Luis, Suriñach, Emma, Vázquez, Juan Tomás
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2003
• Subjects: Subduction zone; Active margin; Trench termination; Tip-line; Antarctic Peninsula; Antarctic; South Shetland Trench; The Antarctic; Antarc*
• Online Access: http://hdl.handle.net/10261/19044; https://doi.org/10.1016/S0040-1951(03)00060-X

22 pages, 10 figures, 1 table. The lateral ending of the South Shetland Trench is analysed on the basis of swath bathymetry and multichannel seismic profiles in order to establish the tectonic and stratigraphic features of the transition from an northeastward active to a southwestward passive margin style. This trench is associated with a lithospheric-scale thrust accommodating the internal deformation in the Antarctic Plate and its lateral end represents the tip-line of this thrust. The evolutionary model deduced from the structures and the stratigraphic record includes a first stage with a compressional deformation, predating the end of the subduction in the southwestern part of the study area that produced reverse faults in the oceanic crust during the Tortonian. The second stage occurred during the Messinian and includes distributed compressional deformation around the tip-line of the basal detachment, originating a high at the base of the slope and the collapse of the now inactive accretionary prism of the passive margin. The initial subduction of the high at the base of the slope induced the deformation of the accretionary prism and the formation of another high in the shelf—the Shelf Transition High. The third stage, from the Early Pliocene to the present-day, includes the active compressional deformation of the shelf and the base-of-slope around the tip-line of the basal detachment, while extensional deformations are active in the outer swell of the trench. We would like to thank the Commander, officers and crew of the B/O Hespérides for their help during the ANTPAC 97-98 cruise. We are grateful for the help of the U.G.B.O. technicians participating in the cruise. The expert help of Emilia Litcheva and Javier Maldonado, who processed the MCS and the swath bathymetry, is appreciated. We also acknowledge the work of Jean Sanders in reviewing the English text and A. Carbó for the release of the Lanzada software. The Spanish “Comisión Interministerial de Ciencia y Tecnología (CICYT)” provided financial ...