Crustal block origins of the South Scotia Ridge

The Cenozoic development of the Scotia Sea and opening of Drake Passage evolved in a complex tectonic setting with sea-floor spreading accompanied by the dispersal of continental fragments and the creation of rifted oceanic basins. The post-Eocene tectonic setting of the Scotia Sea is relatively well established, but Late Mesozoic paleo-locations of many continental fragments prior to dispersal are largely unknown, with almost no geological control on the submerged banks. Detrital zircon analysis of dredged metasedimentary rocks of Bruce Bank from the South Scotia Ridge demonstrates a geological continuity with the South Orkney microcontinent (SOM) and also a clear geological affinity with the Trinity Peninsula Group metasedimentary rocks of the Antarctic Peninsula and components of the Cordillera Darwin Metamorphic Complex of Tierra del Fuego. Kinematic modelling indicate an Antarctic Plate origin for Bruce Bank and the SOM is the most plausible setting, prior to translation to the Scotia Plate during Scotia Sea opening.

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