Andean back-arc basins

Target entity: Andean back-arc basins
Context triple: [Andean orogeny, associatedWith, Andean back-arc basins]

• A. Andean subduction system
  The Andean subduction system is a major tectonic convergent margin along western South America where an oceanic plate descends beneath the continent, driving Andean mountain building, volcanism, and seismic activity.
• B. East Pacific tectonic system
  The East Pacific tectonic system is a major geological region in the eastern Pacific Ocean characterized by active seafloor spreading, transform faults, and subduction zones that shape the surrounding oceanic plates and continental margins.
• C. Cocos–Nazca spreading center
  The Cocos–Nazca spreading center is a mid-ocean ridge in the eastern Pacific where tectonic divergence forms and separates the Cocos and Nazca plates.
• D. Tonga-Kermadec subduction system
  The Tonga-Kermadec subduction system is a major convergent plate boundary in the southwest Pacific where the Pacific Plate descends beneath the Indo-Australian Plate, producing one of the world’s deepest ocean trenches and most active seismic and volcanic regions.
• E. Sunda subduction system
  The Sunda subduction system is a major convergent plate boundary in Southeast Asia where the Indo-Australian Plate is being subducted beneath the Eurasian/Sunda Plate, generating intense seismic and volcanic activity along Indonesia’s island arcs.
• F. None of above. chosen
• G. Unsure - the case is ambiguous/there is not enough information to decide.

Target entity: Andean back-arc basins
Target entity description: Andean back-arc basins are sedimentary basins that formed behind the Andean volcanic arc due to tectonic extension and subsidence related to subduction along the western margin of South America.

• A. Andean subduction system
  The Andean subduction system is a major tectonic convergent margin along western South America where an oceanic plate descends beneath the continent, driving Andean mountain building, volcanism, and seismic activity.
• B. East Pacific tectonic system
  The East Pacific tectonic system is a major geological region in the eastern Pacific Ocean characterized by active seafloor spreading, transform faults, and subduction zones that shape the surrounding oceanic plates and continental margins.
• C. Cocos–Nazca spreading center
  The Cocos–Nazca spreading center is a mid-ocean ridge in the eastern Pacific where tectonic divergence forms and separates the Cocos and Nazca plates.
• D. Tonga-Kermadec subduction system
  The Tonga-Kermadec subduction system is a major convergent plate boundary in the southwest Pacific where the Pacific Plate descends beneath the Indo-Australian Plate, producing one of the world’s deepest ocean trenches and most active seismic and volcanic regions.
• E. Sunda subduction system
  The Sunda subduction system is a major convergent plate boundary in Southeast Asia where the Indo-Australian Plate is being subducted beneath the Eurasian/Sunda Plate, generating intense seismic and volcanic activity along Indonesia’s island arcs.
• F. None of above. chosen