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Free keywords:
Cordilleras, Active spreading subduction, Slab window, Extensional tectonics, Attenuation
Abstract:
We address the possible link between the age of subducting oceanic lithosphere and growth
of elevated cordilleras versus extension-dominated arc regions. Singularity exists in South America:
the lowest elevated Andean segments are found in Patagonia where the active Chile Ridge enters
the trench. Subduction of active ridge triggers thermal doming, crustal extension and attenuation
of former cordilleras. At the Antarctica–South America connection, three active ridge subductions
induced the disruption of a former continuous cordillera during the opening of Drake Passage. Active
ridge subduction induces lithosphere thermal erosion and related crustal extension in the upper plate.
Evolution of regions worldwide experiencing ridge subduction confirms this hypothesis.
