11/07/2025
The ‘Grand Pipe’ of western Grand Canyon is a large breccia pipe. Breccia pipes of northern Arizona are vertical collapse structures, typically a few tens to hundreds of feet across and hundreds to thousands of feet in vertical extent. Grand Pipe formed about 200 million years ago(?), when dissolution and localized collapse of the Mississippian Redwall Limestone produced more than 1000 breccia pipes in the vicinity of Grand Canyon. A small percentage of breccia pipes host economic concentrations of uranium, copper, gold, silver and other metals.
Rock Units:
Ti – Intrusive volcanic rocks (Pliocene & Miocene);
Ph – Hermit Shale (Lower Permian)
Pep – Esplanade Sandstone of Supai Group (Lower Permian)
NOTE: local drainages to the west, south, and east drain into the Grand Pipe.
Citation: Wenrich, K.J., Billingsley, G.H., and Huntoon, P.W., 1996, Breccia-pipe and geologic map of the northwestern part of the Hualapai Indian Reservation and vicinity, Arizona. U.S. Geological Survey I-2522, Map scale 1:48,000. https://ngmdb.usgs.gov/Prodesc/proddesc_10307.htm
