Antarctic Peninsula continental magnesian andesites: indicators of ridge-trench interaction during Gondwana break-up

• Published in: Journal of the Geological Society
• Main Authors: Alabaster, Tony, Storey, Bryan C.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Geological Society of London 1990
• Subjects: Antarctic; The Antarctic; Antarctic Peninsula; Pacific; Antarc*; Antarctica
• Online Access: http://nora.nerc.ac.uk/id/eprint/520275/; https://doi.org/10.1144/gsjgs.147.4.0595

Subduction of young, hot oceanic lithosphere and a major episode of lithospheric extension have been considered as key tectonomagmatic factors in the genesis of ‘Setouchi-type’ continental magnesian andesites. We present data on a new discovery of such andesites from the northern part of the Antarctic Peninsula and propose that subduction of newly created oceanic lithosphere occurred along the proto-Pacific margin of Antarctica during the Middle Jurassic. Continental magnesian andesite magmatism was contemporaneous with the early stages of Gondwana break-up and we suggest that subduction of young, hot oceanic lithosphere and ridge-trench interaction may have contributed to the disintegration of Gondwana by thermally weakening the lithosphere and developing a broad, linear extensional zone along the proto-Pacific margin.