Plain language summary
Topographic growth and morphology of the Andes have been strongly
influenced by subduction processes, tectonic inheritance, and climate.
Here, we investigate the role of subduction of bathymetric highs in
driving continental plate deformation at ocean-continent plate margins.
The subduction of the Carnegie Ridge, a linear bathymetric high on the
subducting Nazca Plate in the Eastern Pacific, has strongly impacted
magmatism and tectonic activity in the Ecuadorian Andes. We employed
radioisotopic dating techniques and numerical modeling to evaluate the
uplift of Andes by exploiting information contained in certain minerals
that record the cooling of rock as mountain ranges are uplifted, and
eroded. The cooling histories of rocks from the Western Cordillera in
Ecuador reveal two distinct phases of cooling. The first phase of
cooling occurred shortly after magmatic bodies were emplaced in the
Western Cordillera. The second phase began after 6 Ma, which we
attribute to the onset of uplift and erosion in the Western Cordillera,
coeval with the last cooling phase in the Eastern Cordillera. Based on
these findings we suggest that the onset of subduction of the Carnegie
Ridge increased the coupling between the two plates and promoted
shortening and regional rock uplift in this part of the Andes.