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Focused subaerial erosion during ridge subduction: impact on the geomorphology in south‐central Peru
Author(s) -
Wipf Martin,
Zeilinger Gerold,
Seward Diane,
Schlunegger Fritz
Publication year - 2008
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2007.00780.x
Subject(s) - geology , ridge , subaerial , subduction , submarine pipeline , geomorphology , continental margin , trench , erosion , paleontology , seismology , oceanography , tectonics , chemistry , organic chemistry , layer (electronics)
Data obtained from low‐temperature thermochronometers such as apatite fission‐track and (U‐Th)/He are combined with morphometric information extracted from digital elevation models. This combination shows several geomorphological effects that are caused by the migration of the Nazca Ridge along the Peruvian Coastal margin. Offshore, the depth of the deep‐sea trench decreases by ∼1500 m where the Nazca Ridge collides with the continental South American Plate. Onshore the ridge causes an uplift of at least 800 m in the Coastal Cordillera. This uplift results in a westward shift of the coastline thereby focusing and increasing erosion in the uplifted areas. At the trailing edge, the shelf subsides and the coastline retreats eastwards, producing at least part of the indentation observed between Paita and Pisco. The Ridge acts therefore like a wave uplifting the Andean margin as it traverses inland and southwards leaving a clear fingerprint on the topographic evolution of the Peruvian coastal margin.