Friday, May 02, 2014

Canyonlands With the Museum of Northern Arizona - 2014

Every year I lead a group of travelers and hikers on a trip to Canyonlands and Arches National Parks for day hikes. The trips are part of the Museum of Northern Arizona's Venture's Program. This program has been functioning as one of the longest running natural history tour programs on the Colorado Plateau. This years trip saw great wildflowers, excellent weather, and congenial hikers!

Locoweed blooming in Negro Bill Canyon. We all agreed that this canyon is in need of an updated name change. The name was changed once from something less flattering. Some local have suggested African American William Canyon. Ha! How about Bill's Canyon.

The stream is so clear, cool and refreshing in this canyon. This is not what most Moab area hikes look like.

At the upper end of the canyon is Morning Glory Arch (it's really a bridge) formed in the Navajo Sandstone.

We saw a hiking group rappel down the bridge.

The Navajo Sandstone in this canyon exposes many limestone beds within the sand bodies. These have been described as oasis deposits within the Navajo erg or sand sea in the Jurassic.

A close-up view of a limestone bed within the Navajo Sandstone.

Next was a visit to the stupendous Fisher Towers, located along the scenic Colorado River Byway (Utah Highway 128). In the background are the La Sal Mountains which can be seen from many vantage points in the Moab area. They has just recently been dusted with new snow.

We wanted to get close to the towers to see the amazing rocks exposed here. As J.W. Powell said, this is erosion on a grand scale!

The sediments are called the Cutler Group and are Permian in age. The cap rock is the Moenkopi Formation of Triassic age. This means that there is an unconformity in the rock record here that represents nearly 50 million years of earth history.

While the towers are the main draw, photographers will find many interesting erosional shapes to occupy their time here.

To the geologist, it is the texture of the Cutler Group that tells the big story here. Within the coarse sandstone and arkose, are many cobbles or boulders of Precambrian age schist, gneiss and granite. This is the debris that came off of the Ancestral Rocky Mountains. When one follows the Cutler beds to the south and west, the deposit becomes finer-grained and more mature. This is what allows geologists to know with precision the ancient landscapes in this area.

After looking at the La Sals from far away, we just had to get close to this laccolith, by taking the La Sal Mountain Loop Road. The snow had just melted and we were among the first of the season to traverse the road.

You never know what you'll find on a desert hike - maybe a juniper tree birds nest filled with luscious peanut M&M's!

An early morning hike to Delicate Arch in Arches National Park is a great way to beat the crowds in the springtime and the lighting is good as well.

The La Sal Mountains framed by the upper part of Delicate Arch. The arch is carved in the Entrada Sandstone, like the majority of the arches in this park.

Reflective time at Delicate Arch.

On another day, we head up to the heights to the Island in the Sky District of Canyonlands National Park. Along the way, one of our participants shared the location of a rock art panel with the group.

These are some of the most impressive and robust Big Horn figures I have ever seen. Thank goodness they are not vandalized!

A straight-on view. These are carved within the Jurassic Wingate Sandstone.

A spiral and other linear elements round out the panel. The black desert varnish that the glyphs are carved into can take thousands of years to develop.

Ekker Butte (left) and Elaterite Butte along the Green River in Canyonlands. Most landforms at this level are cut into a basal slope of Moenkopi and Chinle formations, an upper cliff of Wingate Sandstone, with a small cap of the Kayenta Formartion.

The Green River in the deep valley flows past Upheaval Canyon. The upturned edge of the dome can be seen on the far right.

Deformed strata near Upheaval Dome with the La Sal Mountains in the background.

Ruth perches on a rock above Monument Basin along the Colorado River side of the Island in the Sky.

Monument Basin. The red thin-bedded deposit that makes up the bulk of the spires is the Organ Rock Formation. This is a more distal section of the same rocks seen at Fisher Towers. This far west however, the strata are becoming more defined as they were farther from their mountain source.

Another view of the La Sals. Note the beginnings of a lenticular cloud high over the mountain. When I returned home to Flagstaff one day later, a spring storm would dump 5 inches of snow on April 26.

In the Needles District of Canyonlands National Park is this old cowboy cave. Ranching used to be a big business here but the park was created in 1964 and the grazing leases were gradually retired.

Awesome scene.

A modern pack rat nest found in a niche within the Cedar Mesa Sandstone near the cowboy cave. These piles of debris are excellent for knowing what plants grow within 100 meters of the nest, since that is the distance a pack rat will travel to collect material. Imagine finding a fossil nest, where the feces and urine have cemented the woody material into a substance known as amberrat. Now you can see what was growing within 100 meters of the cave 10,000, 20,000, even 40,000 years ago! A virtual time machine into the vegetation of the southwest during the Ice Age. It's not the same old shit anymore!

What a wonderful group. To take part in next years trip, write to me to reserve your space.

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