There was once ice here

I had the good fortune of changing venue last week and do some hiking in my old graduate research area in Rocky Mountain National Park. Most of my work was done in the library but here on the eastern side of the Colorado Rockies we had the chance to look at some of the evidence left by glaciers. 

In this image you can easily see  the snow field up high, the remnants of the glacier that once filled this valley. I never made it up to the snow in this valley. In other nearby places we were able to see what little blue ice that was left. 

Below the snow lies the terminal moraine of the most recent advance, a small push that we dated about 1850 ish. That date always amazed me because of the advance of white guys and their families across the North American continent while the climate could support a glacial advance albeit a small one.   

Below the highest moraine is a solid rock outcrop that has been shaped by the passage of ice. This roche moutonnee shows ice movement from above downward. The upstream side is smoothed by the ice while the down stream side shows evidence of ice plucking. The ice partially melts by pressure, fills in the cracks and then refreezes with rock chunks stuck to the ice. The rocks move down stream leaving this choppy steep hillside behind.  

Below the image although unseen here is a great U-shaped valley. It doesn't get any more classical-glacial-terrain than here.

To study for my comps, I climbed into a number of these high valleys and physically touched all that the ice had left behind. Not only was it a fun way to study but it must have worked!

rock unit behavior

A few weeks ago I spent some quality time "under the Wingate" my all time favorite Canyonlands rock unit. In fact, the Wingate sandstone has its own facebook page. The Wingate sandstone was formed in the early Jurassic as a large sand sea or erg in the western US. It is quite easy to find cross bedding indicative of sand dunes. The sand grains are all very uniform in size and shape which creates some great erosional formations. In these images you can see how the Wingate has eroded to make some impressive towers. This is a classic formation found once the over-laying Kayenta formation erodes away. The Kayenta formation, is a combination of siltstone, sandstones and even some conglomerates and it acts as a cap rock for the easier-to-erode Wingate sandstone. 

With the protective layers above gone, the uniformed grained Wingate starts to fall apart with equally spaced cracks running vertically down the cliff face. As time proceeds and geology happens the crack widen until there are separate Wingate towers and eventually even they will erode down to nothing. 

This area along the Green River in Labyrinth Canyon shows the whole sequence of events from a large cliff face to totally missing.

The Wingate Towers

 The Wingate Towers head on

 The whole sequence: The left side shows an intact cliff face with an intact cap rock. The towers are found in the center while the right side shows the Wingate missing from the stratigraphic sequence. 

Class time in the back of beyond

Ah field work! well, less field work and more field sharing. This is the time of year where I head into the middle of the Colorado Plateau and share basic geology ideas with K12 teachers. We spend a day on campus at the Colorado School of Mines before we head to Moab UT to spend the next 5 days paddling down the Green River through Labyrinth Canyon. Our classroom is both the modern day transport of material down the river and the mid-Mesozoic climate of the dry arid sand dunes of the Entrada, Wingate and Navajo formations. But, it is not a one direction sharing, sure I do most of the talking but all of the teachers get together and share struggles, concerns, methods and triumphs of getting their students to understand the basic tenets of science. After a winter's worth of reading some newspaper's ideas of how our public schools are doing it is always refreshing to hear from the teachers themselves. It gives me hope about the next crop of scientists who are currently residing in Middle School.

It is truly a week of learning for all participants!

Sunrise on the river!

 Class time on the river.  We barge up and discuss the formations and their forming environments as we float past. 

 Hiking up a side canyon looking for petrified wood and dinosaur tracks. Did I mention that it was 113 degrees F that day? 

 The Wingate above the Chinle

 Moving between classrooms.

The Great Annular Eclipse of 2012

We timed our southwest adventure to coincide with the Annular solar eclipse visible in the western US. The National Park Service helped out by publishing a great web page with an interactive map helping us select which unit of the NPS would have the best viewing.

We chose Bandelier  National Monument in New Mexico. WE arrived a few hours before the event and so hiked around some great Volcanic Tuff outcrops made into cliff dwellings by the Ancestral Pueblos (worthy of a whole blog post by itself) 

When the time came we found a not-too-crowded overlook that faced the west and we sat down to watch. By the time the sun started to disappear there was a good little group watching. We all enjoyed the few who showed up with the proper equipment to directly view the eclipse as we only brought our trusty pin hole camera.

The ruins at Bandelier. The building material is all volcanic.

 Our camera couldn't quite capture the sun with out any filters.

 Our pin hole camera shows the annular eclipse just fine!

Visit to Shanghai

I had the pleasure of visiting China for the past month and although it was not a geology trip per say, geology is hard to ignore since life is indeed a field trip.

I was hoping to blog while on vacation but found that it was a little difficult posting anything while in China.

We flew into Shanghai Pudong airport and it was hard not to notice the low lying fields and what looked like rice paddies near the airport. Driving into the city we were treated to miles (or kilometers) of new construction of massive buildings. The scene of down town Shanghai shows the incredible buildings in the city center. Of course I am from a very small town in the inter mountain west and am unused to buildings over a few stories tall...anyway

What also caught my eye was the amount of water. There are canals and large drainage ditches everywhere. I live in an arid region and I am used to seeing irrigation canals, but these are drainage canals. 

It seems that the whole of the city is built on Quaternary deltaic sediments delivered by the Yangtze river. These sediments, a fine soft clay mixture are similar to what we find in the Mississippi delta region. It makes for great rice fields but not-so-great massive city basement. It seems that most of the new buildings have been built in the top clay layers and some have been sinking from compaction of clay as well as from the subsidence from the use of ground water. 

A water gage on a canal near Shanghai.

The down town at night, including the Oriental Pearl and the Shanghai World Financial Center, the tallest building in China

Geology with benefits

Last weekend I had the chance to visit my favorite Permian formation, the Cedar Mesa sandstone. This formation, part of the Cutler group can be found in southern Canyonlands National Park (both the Needles and Maze) and in the type area on "Cedar Mesa" part of the Monument uplift.

This thick sandstone layer shows not only classic sand dune cross bedding but also some fantastic swirleys where water interacted with the sand. The image below was originally taken because of the hundreds of hand print pictographs (painted on rock art). The image above shows the whole wall. It was only later when I noticed the great swirley of Permian water interacting with a Permian beach.

So, this was a beach environment made with sand eroded from a mountain range that does not exist any more... geology is so cool!

Geo-anatomy of a race course

Last weekend I had the chance to run in the Canyonlands 1/2 Marathon in Moab UT. Except for the wind (It is March in the desert after all) the race was lots of fun with geology at every side. The course follows the Colorado River as it flows south towards Moab.

At the start of the course, you can clearly see many of the typical Canyonland area rock units. Starting at river level is the ever popular Chinle formation of the Triassic period. This area was a large floodplain receiving material from the Uncompaghre uplift to the east. The Chinle is most famous for its uranium ore heavily mined during the 1950's.

Above the Chinle is my personal favorite: the Wingate sandstone. This Triassic aged cliff forming formation- former sand dune is ubiquitous through the Canyonland area. Its reddish hues catch that morning light just right to make the best campsites. Making a region-wide cap rock above the Wingate is the Kayenta formation containing lots of sandstone but also beds of shale and limestone showing a change in climate from sand dunes to at least occasional stream flows.

Another stratigraphic column shot from along the race course.
As the course makes its way to Moab, the late-Triassic Navajo sandstone makes an appearance atop the Kayenta formation. This shows yet another energy regime change away from the streams of the Kayenta to yet another huge sand dunes mass like the Wingate. This image also shows some structure with the ledges of the Kayenta dipping down into the river marking the edges of the Courthouse syncline.
The course doesn't end when the Colorado River reaches the Moab fault and the collapsed salt valley that created the valley where the town sits, there are still over two uphill miles into town left to go.
Over all a very fun run on a most beautiful course.