Incision of canyons into mountains is often interpreted by geoscientists as a proxy for surface uplift of the surroundings by geodynamic and tectonic processes. However, another possible cause for incision is climate change. Richard O. Lease and Professor Todd A. Ehlers of the Department of Geosciences of the University of Tübingen have analyzed the developmental history of a series of 1.5 to 2.5 kilometer deep canyons along a 1250 kilometer portion of the Eastern margin of the Andean Plateau, South America (Peru and Bolivia). They found that Miocene faulting and mountain building of the Northeastern Plateau margin initiated at or before 20 million years ago at the Rio San Gaban catchment, Peru, and was then followed by Pliocene incision of the canyons 4 to 3 million years before present. At the same time as this incision, early global Pliocene warmth shifted to a late Pliocene cooling.
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