Sunday, September 06, 2009

Guide Training at the Amangiri Resort, Big Water, Utah

A brand new kind of resort is soon to open on the Colorado Plateau. There has never been anything quite like it. Located just west of Glen Canyon Dam off of US Highway 89, the Amangiri Resort sits on 600 acres of private land tucked between the Glen Canyon National Recreation Area and Vermilion Cliffs National Monument. On Friday, September 4 I conducted a field-based, geology training session for the resort staff. The property is spectacular and contains world-class exposures of an ancient sand dune complex (Entrada Sandstone) and a coarse shoreline deposit (Dakota Formation).

View to the west on the Amangiri property. The resort sits in front of the spur of sandstone in the top portion of the valley floor.

The staff are developing a climbing route called the Via Ferrata, named after the famous traverse in the Italian Dolomites. Here we climb through the Entrada Sandstone on the way to the mesa top.

View of the contact between the Middle Jurassic Entrada Sandstone below (165 Ma)and the Late Cretaceous Dakota Formation (105 Ma). An unconformity of 60 million years separates these rock units and developed when the southern Colorado Plateau was uplifted in the Early Cretaceous during the Nevadan Orogeny.

Numerous bolts with steps have been set in the rocks. Climbing specialists will help willing guests to make the climb up the cliff face and across the geologic contact.

Close-up view of the resort property from atop the Via Ferrata climb.

View from the top of the mesa towards the resort property.


A loop hike brought us to another great canyon cut into the Entrada Sandstone. An obvious break in the cliff is evident here, yet both packages of this sandstone belong to a single rock unit. Future studies may one day segregate these sand bodies into separate formations (or members) but this distinction is restricted only to the local area.

Fantastic tafoni structures within the Entrada were seen along the route. Note that these are not distributed randomly throughout the rock, but rather form preferentially along the cross-bedded surfaces (angled lines) or the bounding surfaces (horizontal lines). Before the sandstone was exposed to erosion, groundwater moved along these planes and gradually weakened the sandstone cement. When the rock was finally exposed, the pockets of weakened sand grains eroded out more rapidly than surrounding areas.

Hikers on the Via Ferrata, Amangiri Resort, Utah

4 comments:

Gaelyn said...

This looks like an interesting place. I'll have to check it out.

Anonymous said...

Wayne,

Thanks for sharing. Beautiful country.

Eluterio

Gavin Macfie said...

Great posts. I'm planning a trip to Utah in the spring so it is great to read about your trips.

ANN said...

Hearing about the trip in September was no where close to the joy it must have been to be on it, but wonderful to read about. The pix were great. Thanks, Ann