Comment on "Age and evolution of the Grand Canyon revealed by U-Pb dating of water table-type speleothems".

نویسندگان

  • Joel Pederson
  • Richard Young
  • Ivo Lucchitta
  • L Sue Beard
  • George Billingsley
چکیده

Polyak et al. (Reports, 7 March 2008, p. 1377) reported speleothem data leading to their inference that the western Grand Canyon incised much earlier than previously thought. This contradicts several lines of published geological knowledge in the region, hinges upon unjustified hydrogeological assumptions, and is based on two anomalous data points for which we offer alternative explanations.

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عنوان ژورنال:
  • Science

دوره 319 5868  شماره 

صفحات  -

تاریخ انتشار 2008