A Day in the Teton Mountains

You haven't seen mountains until you have been to the Teton mountains in Wyoming. Reaching elevations of close to 14,000 feet, these mountains touch the clouds! Today, MCC's field studies Geology group took a nice ten minute boat ride across Jenny Lake. Jenny Lake is a lake that was specifically formed from the melting of Teton's most recent glaciation, the Pinedale, which was dated to be around 70-13 thousand years ago. During the mile long hike, the group saw a specific type of metamorphic rock called gneiss which had pegmatite veins of quartz pegmatite.  And of course, granite was also found on the trail. Although the weather was rainy, cold, and cloudy, the group was determined to make it to Inspiration Point, which had the best view of Jenny Lake and the ancient moraines that hold the lake in place and the outwash plane that formed thousands of years ago. 

But the question remains about how these massive mountains formed. The Tetons are on a fault which is a specific place where there is crustal motion. The name of this fault is the Teton fault and long ago the land was pulled apart due to tensional stress. As the land eroded away, the less erosive metamorphic rock stayed creating these spectacular mountains. 

 Next to the Teton Mountains there is an end moraine which is composed of unsorted sediments. These sediments were deposited during the receding of the Pinedale glaciation. This also help form many of the lakes at the base of the Tetons. You can tell that it's a moraine due to the fact that there are pine trees growing along the moraine due to its low permeability. Beyond the moraines are stream terraces, flat region steps adjacent to the base of the mountain, that are formed by the Snake River. The river down cuts when the base level drops, also this is the river's response to the uplift of the region. 

On a couple of the mountains you can see some features such as arêtes which are basically a narrow, sharp edged ridge, as well as U-shaped valleys. Both of these features are due to valley glaciers. The Tetons have three glaciers the Teton, Teepee, and Middle-Teton glaciers. During the last 40 years these glaciers have lost 25 percent of their total surface area. 

Excelsior Geyser

On June 15th we visited Excelsior Geyser, located in the Lower Geyser Basin of Yellowstone National Park. This geyser used to erupt up to 300 ft before the 1900's but now it is a dormant geyser. Scientists believe that this geyser was so violent that it actually damaged its internal structure to the point where it didn't have access to its hydrothermal energy. In laymen's terms it lost access to its heat source. Although it doesn't erupt as it did, in 1985 it erupted for two days but it was only 20 to 80 feet tall-- a fraction of what it used to be. Present day it is considered a thermal spring and releases about 4050 gallons per minute! Unlike Grand Prismatic Spring the coloring in this spring is blue due to minerals rather than bacteria that cause coloring in Grand Prismatic. There was so much steam that we couldn't even see the spring until some wind picked it up and cleared the spring.

What's that smell?!?

You're standing on the bank of a steaming, hot, brownish mixture of what appears to be mud and water. The breeze hits your face and you immediately smell a wretched stench equivalent to the permeating odor of week old rotten eggs. What could that be, you ask? Acid sulfate from a mud volcano. Volcano as in oozing lava? Not really, these mud volcanoes are different because heat and gas from deep in the old magma chamber rise up heating the ground water at the surface of the Earth. And if you think Geology is the only thing going on here, think again! Tiny micro organisms called extremophiles live in this high acidic, high temperature environment and convert the volcanic gases into Hydrogen Sulfide which in turn eats away at the Rhyolitic rocks turning them to clay which gives the water its brownish tint. Through Geology, Chemistry, and Biology, these mud volcanoes flourish in Yellowstone National Park. 

How did these "chocolate volcanoes"get here, you ask?

Long ago, Yellowstone had a very gargantuan Rhyolitic eruption about six hundred and forty thousand years ago that covered two hundred square miles of debris and ash. That's the equivalent to two thirds of the United States! But don't think she's done yet! Deep below the Earths's crust,a very specific yet simple process is still occurring. Lots of heat and volcanic gases rise to the surface of the Earth through weak points in the thin crust. And what happens when water meats heat? The scientific term is called Hydrolysis but I would refer it to a bubbling cauldron of stinky Rhyolite micro organism soup! You want some? I wouldn't recommend it. This brown broth can sometimes reach temperatures of more than one hundred and fifty degrees Fahrenheit. Not to mention a few antacids wouldn't help the acidity or chemical burns you would get. If I were you, I'd stick to the picture taking.

Please view our educational video that features an active mud volcano in Yellowstone National Park  

http://youtu.be/_nhxpkhPK0s

Independence Rock - 6/11/14

Independence Rock

Independence Rock is a stock feature, meaning that it is an igneous mass that was formed underground, but is smaller than a batholith. However, it can become one if it becomes more exposed above the surface. It was formed along normal faults meaning the hanging wall moves down from tensional stress. 

On a historical level it is one of the features on the Oregon trail. It was also a landmark used for cavalry and landrushers in 1849 and a check point for the Pony Express.  Many people have inscribed their names into the rock (and surprisingly it proves boys once had nice handwriting) and wagon ruts can often be found near it.

Other features found on the rock include coarse-grained mineral veins. The veins found throughout the rock are made up of quartz. These quartz veins are formed when hydrothermal fluids, or hot water solution, runs through the rock.

The uplift of the rock results in erosion of overlying rock, which causes a decrease in pressure and the rock to expand and fracture. Next, Independence Rock began exfoliating along sheet joints. The granite of Independence Rock weathers in blocks that then round out. This process is called spheroidal weathering.

Also of note, Independence Rock is an exfoliation dome, meaning it is a large dome shaped rock formed by exfoliation. Exfoliation is a process that includes the removal of concentric layers of rock along sheet sheets.

In terms of mineralogy and rock properties, the rock is made up of a typical granite composition, with a bit of a unique property. While it still has typical "Orthoclase - Quartz - Hornblende" composition, it is unique in that parts of the rock actually have a porphyritic phaneritic texture. This proves that this rock began the cooling process underground. The crystals that were much larger cooled at a much higher temperature, for a longer period of time, whereas the smaller crystals cooled much quicker at lower temperatures as the magma moved closer to the surface.

Overall, I would say that exploring Independence Rock was a pretty incredible experience. It was a challenge to climb up, and many of us felt the 3700 ft. elevation difference, compared to Rochester, NY, while climbing it. Once on top though, the view was astonishing. 

Thanks for reading! For more pictures from this trip, feel free to visit Brandon's Tumblr page at: 

http://www.tumblr.com/blogs/Yellowstone-Adventures

Cheers!

Cindy & Brandon

 

Pumpkin Buttes, Powder River Basin, Wyoming

    Along the way to Devils Tower, we passed through the Powder River Basin, Wyoming.  This region is know for its abundance of natural resources and this is very evident by oil fields and coal mines.  Uranium has been a more recent discovery is the area as well.  Most of the area is relatively flat and featureless beside the buttes.

     During the Eocene epoch, between 55.8 to 33.9 million years ago, after the inland sea of the Cretaceous withdrew, the climate was very wet and warm at the time, producing swampy low lands.  In these lowlands, the Wasatch Formation was created.  Fresh water sandstones, shales, clays, and coal beds with fossil remains we're deposited here.  Region uplift and erosion occurred soon after.  

     It is believed that lightning a strike ignited the exposed coal bed mixed with clay, leaving the red/orange/black layers seen on the upper portions of Pumpkin Buttes.  This is called 'clinkers' and are more resistant to the effects of weathering than the surrounding landscape, thus creating the mounds you see today.  

     This has great cultural importance to the Native Americans.  They lived around the buttes and used them to spot settlers for raids.  They say the buttes had the color of gourds and that is why we call them Pumpkin Buttes.  Settlers used the buttes as a welcome waypoint on their travels westward.  It is also associated with the Teapot Dome Scandal in which a politician took bribes to pass legislation to drill and mine for natural resources on protected land.

     We all noticed how flat and vast this area of Wyoming is.  It was just as much as a relief to us as it must have been for settlers to have the Pumpkin Buttes as stopping point.

   

Brandon sizing up a 1.7 billion year old boulder of gneiss from the Farmington Canyon Complex in Antelope Island State Park, Salt Lake City, UT. For detailed info on the geology of Antelope Island, read here!

Great Salt Lake

Today we went to the Great Salt Lake.  It was amazing and gross at the same time.  Waves of gnats infest the shoreline but they are crucial to the environment.  Wildlife all around are ultimately dependent on these insects.  

We learned that before the Salt Lake existed a larger glacial Lake Bonneville was present.  A catastrophic flooding event caused it to drain northward to Canada, leaving the Salt Lake behind. Uplift in the region during the Laramide  orogeny created the Wasatch range (part of the Rocky Mountains) we see today.  

The Great Salt Lake is a playa lake which occurs when the surrounding mountains erode salts into intermountaine basin, which is essentially a valley.  The dry, arid region contributes to extensive evaporation which leaves the water salty.  We found oolitic limestone sands and rocks.  We put are feet in the water and took many pictures.  We also saw our first bison.  

  Here we are at Weber State College, where we will stay our first night.  We almost got caught in the spinkler system writing this blog, who who!