Sunday, April 19, 2015

Can’t Get Enough of Canyonlands

For someone who can’t get enough of a place, I certainly don’t go there very often. I went maybe thirteen years ago to visit friends living in Moab, Utah, and to watch the Perseid meteor shower on a moonless night in Arches National Park. It is not that far from my home, really, as far as western distances go – just over 300 miles away, barely five hours and change. My friends still live there.
010ShaferTrail
Shafer trail takes off near Island in the Sky visitor center - La Sal Mountains in distance

Time gets away from us, though. Life happens. I don’t know what took me so long to return, but I knew that I wanted to reconnect with my old friends once again. I also hoped to hike in Canyonlands, if only for a few hours. With all that in mind, I chose a weekend to invite myself and made it happen.
017Wingate Sandstone
Massively vertical cliffs of Wingate Sandstone dominate the Island in the Sky area

Lee had to work, but Alicia was happy to oblige. She is a patient soul, delighted to show me her side of our state and more than willing to indulge this geology geek’s passion for photographing rocks. We were in absolutely no hurry on this gorgeous early spring day.

020GreenRiver
The incised meander of the Green River (upper left) courses through Canyonlands


Just as the Navajo Sandstone does in Zion National Park, the Wingate Sandstone forms massive vertical cliffs in Canyonlands. Both are eolian, or windblown, sand dune deposits, although the beds of ancient river systems appear to occur within the Wingate.

In the Island in the Sky area of Canyonlands, we hiked across Early Jurassic rocks of the Glen Canyon Group. The Wingate, which does not outcrop in the Zion area, is around 200 million years old, older than the Navajo Sandstone by perhaps 10–15 million years or so. In Canyonlands, the Kayenta Formation is sandwiched thinly between the Wingate and the overlying Navajo Sandstone.

029Canyonland Spire

Beneath the Wingate are the familiar Triassic mudstone and siltstone slopes and ledges of the Chinle and Moenkopi Formations. Below that are older strata and formations I have heard of but rarely encounter. In Permian times, southwest Utah was alternately submerged beneath a shallow sea or exposed as a broad, flat coastal area called a sabkha, where limestones and siltstones of the Kaibab and Toroweap Formations were deposited. Here in eastern Utah, though, Permian rocks of the Cedar Mesa Sandstone, Organ Rock Shale, and White Rim Sandstone paint a somewhat different but related picture. My simple, broad explanation is that these eastern Utah rocks were deposited in an environment that was a bit further from the edge of the supercontinent Pangaea than that found in southwest Utah. Same time, different environment.

026Canyonlands

I discovered something this weekend, about the relation between rocks of the same geologic time period that are separated in space by mere hundreds of miles. Seeing the Permian rocks of Canyonlands, a light bulb went on in my brain. I had a Eureka! moment. Another piece of the geologic puzzle fit. I really must not wait another thirteen years before I get over there again. I can’t get enough of the place. Alicia is too good of a tour guide!

028Canyonlands TourGuide
Tour guide extraordinaire!






2 comments:

  1. Canyonlands is such a beautiful place. I've been there many times, but always with students, with brief stops at the same places. I finally got out to Mesa Arch last time. What a marvelous sight! Good article!

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    1. Thanks, Garry - Like I said, I just don't get there often enough, even though it is not that far away. Plus my friends offer great couch surfing accommodations! I still have another post or 2 up my sleeve...

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