Friday, February 27, 2015

Patagonian Adventure Begins on February 28!

Join me on the Earthly Musings blog site as I partake in a Smithsonian Journeys expedition to Patagonian Argentina and Chile beginning on February 28. I will serve as the Study Leader for 22 folks from around the USA. You can view the itinerary here and I will be posting photographs and stories as often as possible.

Wednesday, February 25, 2015

Hiking the Boucher and Hermit Trails in Grand Canyon

During the second week of February, I was able to complete a five-day backpack on Grand Canyon's Boucher and Hermit trails. It had been a number of years since I hiked on the Boucher Trail and it was as difficult and enjoyable as I remember.

We camped the first night beneath Yuma Pt. on the Boucher Trail.

Bryan B. near the tinajas (potholes) at Yuma Pt. These pools of water are often dry at Yuma Pt.

The Grand Canyon from Yuma Pt. The early morning light was fantastic!

Not only could we see Granite Falls on the Colorado River from Yuma Pt., we could also hear the rapid!

Drought-stricken Grand Canyon. The piƱons are the ones that seem to go first, the junipers are more hardy with their deeper root systems.

Many famous artists have used this location to paint the Grand Canyon and there are some known paint remains on the wall near here.

Midway through the Redwall descent on the Boucher Trail. There was lots of shade this time of year which we sought out most times.

Bryan B., Frank R., and Norm H. - great hiking and trail buddies!

On the way from Boucher Creek to Hermit Creek, I passed a block of Redwall Limestone encrusted with desert vegetation.

Looking towards Hermit Rapid on the Colorado River from the Tonto Trail.

Same view framed by yucca's.

Looking back to the west of Boucher Rapid on the Colorado. Note the Great Unconformity just below eye level across the river. More than 1,200 million years of the rock record is missing here.

Spectacular view of the Inner Gorge of Grand Canyon upstream from Hermit Rapid. Zoroaster Temple in the far background.

My campsite at Hermit Creek.

Making our way out to the South Rim. The Hermit Trail is 8 miles long but feels like 10 on the way out.

Bryan B. at Santa Maria Spring along the Hermit Trail.

Trace fossils of Chelichnus gigas in situ along the Hermit Trail. Note the tail drag between the set of footprints. These tracks were likely made by a mammal like reptile some 275 million years ago.

We stopped at Pima Point after the hike to look over the area just hiked. The air clarity was fantastic!

Saturday, February 14, 2015

Geology of the Garden of the Gods, Colorado

At the end of January, I was fortunate to visit the Rocky Mountain Front Range, scouting an itinerary for a tour group back east. One of the highlights was a visit I made to the Garden of the Gods City Park in Colorado Springs. For years I have heard about and seen photos of this exceptional geo-scape. I was happy to finally see it in person.

A view of the entrance road off of 30th Street in Colorado Springs. The snow capped mountain in the background is Pikes Peak, elevation 14,115 ft. or 4,302 meters. As you can see the weather was fantastic during my visit, although it plays into the recurring dryness we are having here out west this winter.

Nearing the red rocks found on the main loop road. These are upturned sedimentary rocks. Pike's Peak in the background is composed of the 1.1 billion year old Pike's Peak Granite. This was intruded into the crust during the Grenville Orogeny, a mostly eastern seaboard mountain building event.

A private citizen, Charles Elliott Perkins, had bought the land that contains the Garden of the Gods and wished to make it a public park in perpetuity. His estate made sure this came to pass and it remains one of the most striking city parks anywhere - at least for the geologist and scenery seeker.

Here is a cross-section of the upturned strata along the Rocky Mountain Front Range at Garden of the Gods. In this section, the Rocky Mountain uplift would be to the left, the Great Plains to the right. Just off the section to the left is the Precambrian basement rocks. These are overlain by the Fountain Formation (here called Arkosa or arkose). The Fountain Formation is the tectonic and age equivalent of the Cutler Formation (or Group) on the Colorado Plateau. Both of these sedimentary packages resulted as outwash from the Ancestral Rocky Mountains some 300 to 250 Ma. The Lyons Sandstone provides much building rock and flagstone here in Colorado and beyond. The Morrison Formation contains numerous dinosaur fauna and the Pierre Shale is the equivalent of the Tropic and Mancos Shales on the Colorado Plateau. This is a classic section of strata!

The next series of photos are taken from a few of the paved walkways that meander through the rock formations (the "Gods").

These were once horizontal beds of the Fountain Formation but uplift during the Laramide Orogeny (70 to 40 Ma) pushed them upright. The harder conglomerate beds resist weathering and stand tall between the intervening and eroded softer shales and mudstones.

A juniper tree frames Pike's Peak.

View to the north of upturned beds of sandstone and conglomerate.

Note where the softer beds of shale and mudstone have been removed by weathering and erosion to create spaces between the fins.

The hills in the upper left are Precambrian crystalline rocks, which underlie these red beds.

A few fin tops have tumbled into the voids.

Close-up of the coarse conglomerate present in the Fountain Formation. These clasts were derived from the Precambrian bedrock that was exposed during the Ancestral Rocky Mountains uplift in the Pennsylvanian and Permian time periods. Rivers carried the debris out onto the floodplain where it became lithified into the Fountain Formation. The same scenario played out on the western side of the ancient range to become the Cutler Formation.

View to the east through a break in the fold.

History is alive here as well. Many Native tribes used the area as a well-trodden path led to a low pass in the Rocky Mountain front.

A view of Balanced Rock on the south side of the city park. Note the clasts in the conglomerate within the top bed. Balanced Rock formed as softer units were preferentially weathered out from under the tougher beds - slowly enough that the rock hasn't yet toppled.

Another view of Balanced Rock showing its precarious balancing act. Note the general dip of the beds on its pedestal. This shows that Balanced Rock has actually tilted back toward the left to maintain its upright position.

Anyone visiting Denver or Colorado Springs should pay a visit to this unique park and landscape.