Classic Rock Tours 3. Grand Canyon Geology, One Hundred and Fifty Years after John Wesley Powell: A Geology Guide for Visiting the South Rim of Grand Canyon National Park

摘要

The year 2019 is the 150thanniversary of John Wesley Powell’sepic exploration of the Colorado River through GrandCanyon and the 100thanniversary of the establishment ofGrand Canyon National Park. This is an excellent moment tolook back 150 years to think about where we have come fromas a science and society, and look forward 100 years towardsthe accelerated change we expect in the future. For historians,archaeologists, geologists and astronomers, of course, this cen-tury-long time scale is short compared to other perspectives.They might choose also to celebrate the 479thanniversary ofthe first sighting of Grand Canyon by Europeans in 1540, the1000thanniversary of Ancestral Puebloan farmers in GrandCanyon, the 12,000thanniversary of the arrival of humansmigrating south from the Bering Land Bridge, the 5 millionthanniversary of the integration of the Colorado River throughGrand Canyon to the Gulf of California, the 4.6 billionthanniversary of the formation of Earth, or the 13.75 billionthanniversary of the Big Bang and the formation of our Uni-verse. Geology is all about time, and knowing some geologyhelps with the difficult endeavour of placing human time-frames into perspectives of deep time.