2012/11/30 by Rebecca M. Flowers, Kenneth A. Farley · 1 citation
Earth and Planetary Sciences · #Geological and Geochemical Analysis #Geology and Paleoclimatology Research #earthquake and tectonic studies #Canyon #Geology #Erosion #Archaeology #Paleontology #Geomorphology #Geography
paper · doi:10.1126/science.1229390
openalex publication_date 2012/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
The Grand Canyon is one of the most dramatic features on Earth, yet when and why it was carved have been controversial topics for more than 150 years. Here, we present apatite (4)He/(3)He thermochronometry data from the Grand Canyon basement that tightly constrain the near-surface cooling history associated with canyon incision. (4)He/(3)He spectra for eastern Grand Canyon apatites of differing He date, radiation damage, and U-Th zonation yield a self-consistent cooling history that substantially validates the He diffusion kinetic model applied here. Similar data for the western Grand Canyon provide evidence that it was excavated to within a few hundred meters of modern depths by ~70 million years ago (Ma), in contrast to the conventional model in which the entire canyon was carved since 5 to 6 Ma.