George Davis (’64), meet Tricia Hall (’14)

June 8th, 2013

EPHRAIM, UTAH — Generations of Wooster geologists were united today over a common interest:  deformation bands of Utah!!

George Davis (Regents Professor Emeritus and Provost Emeritus, University of Arizona) researched the deformation bands of the Colorado Plateau region of Utah and wrote several very detailed manuscripts.  As we work on a structural analysis of the Sixmile Canyon Formation, we have been using two of his publications rather extensively this past week:  “Structural Geology of the Colorado Plateau Region of Southern Utah, with Special Emphasis of Deformation Bands”…and…”Conjugate Riedel Deformation Band Shear Zones”.

I actually thought that it was a unique twist of fate that Tricia and I were pouring over two of George’s publications last night…and putting our knowledge into use today in the field.

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Above is a view of the Sixmile Canyon Formation, the focus of Tricia’s study.  It contains wonderful deformation bands and joints, and it just happens to be located next to two characteristic antithetic normal faults that cut the Wasatch Plateau.

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Tricia and I stumbled upon these deformation bands early in the morning…

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…and these later in the afternoon.  With all of the deformation bands in the area, we felt like “measuring machines”.  Indeed, we could have used help in the field today from fellow Brunton-lovers!!

In addition to looking for conjugate deformation bands that George describes from his work in southern Utah, we were also trying to identify characteristic “ladder structures” that he identified in the Sheets Gulch area.  Tricia is sampling the deformation bands for further thin section analyses to determine if they show any sign of cataclasis.  Ultimately, she would like to classify the deformation bands, using one of the kinematic classification schemes proposed in the literature.

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Here’s Tricia gathering what she considers to be a “small” sample from a prominent deformation band.  You can tell how excited she is about her I.S.!!

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One characteristic of this part of the Sixmile is the interesting iron “concretions” that are everywhere.  The photo above shows how abundant that they can be within the unit.

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Aren’t these awesome??!!  These iron “chimneys” rise right out of the rock.  Tricia and I will be further investigating the abundance of morphologies of these concretions tomorrow, as we try to tackle some interesting paleo-fluid fronts within the Sixmile.  The past two days have been rather safe in the field, because we saw few mountain lion prints at our localities.  But, tomorrow is another day, and we are hiking back up to the areas where we saw extensive mountain lion “trace fossils”.

Mountain lions and deformation bands: just another day in Utah

June 6th, 2013

Guest Blogger:  Tricia Hall

SIXMILE CANYON, UTAH — After a couple of days seeing a good number of mountain lion footprints, Shelley and I have decided that it is best to turn the attention of my I.S. toward using our new Trimble GPS to track mountain lion movements. We have heard from the local residents that the lions are low in the mountains, and have even ran across a potential “lion den”. Along the way, just in case this project does not pan out, I have measured a few deformation band orientations so that I don’t fail I.S. Just kidding! Here’s what we’ve really been up to the past couple of days….

Yesterday, we tackled the faulting and joint sets within the Flagstaff Limestone to the west of the Sixmile Canyon Formation exposure. The Flagstaff unconformably overlies the Sixmile, and the faulting and jointing relationships will be key in interpreting the deformation bands within the Sixmile Canyon Formation. We made good use of the Trimble to map the Formation and the fault (to the best of our ability). The resulting map, even without postprocessing, shows normal faulting within the Flagstaff complete with drag folds.

Above is the jointed Flagstaff Limestone looking to the north. We measured several units of this formation to determine the offset of the faults. In addition to the Trimble, we used the brand new Laser range finder! It was either the range finder or eye heighting up the mountain...I was all for the former.

Above is the jointed Flagstaff Limestone looking to the north. We measured several units of this formation to determine the offset of the faults. In addition to the Trimble, we used the brand new Laser range finder! It was either the range finder or eye heighting up the mountain…I was all for the former.

After a long day yesterday, we made it out to Sixmile Canyon this morning with the intention of measuring the major joint sets in the morning followed by deformation band measurements in the afternoon. The joint sets were harder to find than we thought, but hopefully after we go through today’s data after I’m done blogging we’ll find that we’re okay on joint sets. The afternoon was pretty warm, but there was work to be done. It was finally deformation band time! We began measuring orientations, collecting samples, and yes, we broke out the Schmidt Hammer. Schmidty proved most effective and will be put back to work tomorrow. We’re well on our way to our self-imposed 300 Schmidty hits!

Schmidty was phenomenal on the deformation band shown above.

Schmidty was phenomenal on the deformation band shown above.

We’ll check in later, back to Sixmile Canyon tomorrow!

A visit to the Natural History Museum of Utah

May 29th, 2013

NHMU052913SALT LAKE CITY, UTAH–On the last full day of our Utah trip, we toured the Natural History Museum of Utah in Salt Lake City. It is in a spectacular place against the red rocks of the Wasatch Mountains and looking over the Salt Lake Valley. This museum has only been open since November 2011. Its exhibits are very up-to-date and modern.  (My test for recent accuracy is whether birds are acknowledged as dinosaurs and if Australopithecus sediba is in the human evolution section.) I’d like to just share some images from the museum and encourage anyone in Salt Lake City to visit it.

EoceneLake052913Dr. Judge will be impressed with the attention paid to exhibits on the Green River Formation (Eocene). This tableau is designed to show animals in the water (below) and on the beach (above). Note the stromatolites on the shoreline representing some of the features she and her students have worked on in the Green River Formation.

585_Deinosuchus_hatcheri_052913Utah is extremely rich in Mesozoic vertebrate fossils. Here is an impressive skeleton of Deinosuchus hatcheri from the Cretaceous.

CeratopsianWall052913The dinosaur exhibit is world-class. Here is a wall of ceratopsian dinosaur skulls showing evolutionary relationships.

DinoPelvis1_052913My History of Life students are well trained in sorting out major dinosaur groups by their pelvic bones. They could tell you, for example, if this is an ornithischian or a saurischian dinosaur.

DinoPelvis2_052913And this set is of the other group. Can you see the differences?

dinohead052913It appears this dinosaur had barnacles for eyes!

PaleontologistsBehindGlass052913Here is the classic paleontologists-behind-glass exhibit of a working laboratory. (I wonder why they never put working petrologists on display?)

NHMUview052913The architects knew exactly what they were doing when it came to designing the building to take full advantage of the setting. The Salt Lake Valley is fully visible from every floor.

What a great place to end our little Utah excursion this year. The real Team Utah of Wooster Geology will be back in the state next month.

Ancient islands

May 27th, 2013

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LOGAN, UTAH–Today we explored the area around Promontory, in northern Utah. Among the many beautiful sites were these rocky, faceted hills that several thousand years ago. This particular hill was intriguing although inaccessible. (It is on a vast tract of land owned by the rocket company ATK. Trespassing is discouraged and no doubt at times very discouraging!) You can see this feature on Google Maps at 41° 37′ 21.11” N and 112° 21′ 42.28” W. Note the cone shape of the top that appears to be sitting on a flat layer beneath. That flatness is a beach terrace of ancient Lake Bonneville. It was formed 14,500 to 16000 years ago by wave action eroding away the hillsides, with the pinnacle exposed above water. (I love wave-cut terraces. Wooster Geologists have noted them before in this blog.)

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Here is a Google Earth view of the scene from the south and above. You can see the terrace cut deeply into the hill and extending to the sides. The highway below is where we stopped for the top photograph. Now note that curvy structure of rocks in the lower right of the above image. A close-up of it is shown below.

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This is a plunging fold. I can’t tell if it is a plunging anticline or syncline because I couldn’t visit it. You can make it out on the lower right of my photograph at the top of the page. These rocks are mantled with sediments from Lake Bonneville. In this case the sediments are coarse sand and gravels because of the lake energy at this shoreline. The exposed rocks are limestones, probably from the Paleozoic.

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On the other side of the valley, on the northwest end of the Wellsville Mountains, two terraces can be seen. The top one against the mountain is the 14500-16000 year-old one we saw throughout the Promontory region. The lower one is younger and made after lake levels dropped precipitously following a catastrophic flood through Red Rock Pass in southern Idaho (which I visited three years ago and recorded in this blog). Note on the lower left that it is being mined for sand and gravel. We see this throughout the area because these terrace deposits are so well sorted and useful in making concrete, building roadbeds, and the like. I learned recently that these kinds of deposits are in a category called “alloformations” because they are laid on top and against much older units.

Oh yes, and what else happened in Promontory, Utah? May 10, 1869!

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The Lodgepole Limestone Formation

May 26th, 2013

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LOGAN, UTAH–Today we hiked up part of Logan Canyon along the south side of the Logan River. Towering above us on either side were massive limestone cliffs, as shown above. The thickest unit is the Lodgepole Limestone Formation (Lower Carboniferous, Tournaisian — about 350 million years old), which is well known throughout the northern Rocky Mountains. I’ve long admired its extent and consistency. It testifies to a shallow carbonate platform that extended from what is now Utah, and Colorado up into central Montana. In fact, correlative carbonates by other names are found from Arizona (the Redwall Limetone) well into Canada. I’ve also been impressed with those many paleontologists over the past century and a half who have managed to pry fossils out of its concrete-like matrix. When they do they have beautiful bryozoans, brachiopods and rugose corals. Some of the best are silicified and removed by dissolving the calcitic matrix from around them.

View of the northern side of Logan Canyon, Utah. The Lodgepole Limestone Formation makes up the major cliff on the right.

View of the northern side of Logan Canyon, Utah. The Lodgepole Limestone Formation makes up the major cliff on the right.

The Lodgepole Limestone Formation is part of the Madison Group of mostly limestones and dolomites. Most of these rocks are affected by karstic weathering, so the terrain often has disappearing streams, sinkholes and caverns.

While the carbonates of the Lower Carboniferous were being deposited in western North America, mixed siliciclastics dominated the east. Last semester’s Sedimentology & Stratigraphy class studied some of those rocks on their field trip to Lodi and the southern edge of Wooster, Ohio. It is always fascinating to look at very different sediments deposited at the same time in different places.

Wooster Geologist on the Wasatch Front in northern Utah

May 25th, 2013

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SALT LAKE CITY, UTAH–It may be a vacation, but even so, every geologist has the delightful duty of enjoying the local geological setting. The above image is looking south from the University of Utah campus in Salt Lake City along the Wasatch Front and the snow-dappled Oquirrh Mountains. We’re standing along the Wasatch Fault, which extends north-south from southern Idaho to central Utah. It is a large normal fault that marks the eastern edge of the Basin & Range Province. It is a beautiful setting for a campus.

Wooster GSA 2012 Poster Take Three

November 6th, 2012

CHARLOTTE, NC – Five Wooster geologists presented their work on day three of the conference.

Whitney Sims (’13) presented her  IS on the emplacement of lava flows in the Ice Springs Volcanic Field (Team Utah). Here is her abstract.

Anna Mudd (’13) presented her work on a Middle Miocene paleosol from the Powder River Volcanic Field (northeast Oregon). Here is her abstract.

Jenn Horton (’13) answered questions about her study of the glacial history of Adams Inlet in Glacier Bay National Park and Preserve (southeast Alaska). Here is her abstract.

Lauren Vargo’s (’13) poster described how she used tree rings to understand North Pacific volcanically forced cooling and drought in midwestern North America. Here is her abstract.

Andy Nash (’14) showed how he used tree rings to investigate drought in northeast Ohio. Here is his abstract.

Tomorrow is the last day of the conference, when we’ll get to see the final two talks and two posters.

The second group of Wooster GSA 2012 posters

November 5th, 2012

CHARLOTTE, NORTH CAROLINA–Matt Peppers (’13), a member of the intrepid Team Utah, presented his poster today at the 2012 Geological Society of America annual meeting. Matt is working on the dynamics of the volcanic flows in the Black Rock Desert. Here is his abstract.

Melissa Torma (’13) showed her poster in the same session. She worked in the Negev of southern Israel on the Middle Jurassic Matmor Formation fauna. Her GSA abstract is here.

The third Wooster presenter was Richa Ekka (’13), who worked on Saaremaa Island in Estonia this summer. Her abstract describing her project with a Silurian shallow water dolomitic sequence is here.

Once again it was a joy to watch our students interact with the many geologists who discussed their posters and projects. I now can’t imagine coming to these meetings without an enthusiastic group of our students.

A day in the Wasatch Mountains

June 21st, 2012

Ephraim, Utah-[Guest blogger Tricia Hall]

After a couple of productive days measuring deformation features and joints, Dr. Judge and I took a day for a fun drive up into the Wasatch Mountains and Plateau. The scenery was much different from that of the desert we were used to. From Ephraim, we headed north climbing onto the Wasatch Plateau. The views were spectacular, and we made sure to stop at every possible place to take in the landscape.

The best vehicle for getting up a mountain...plus it's easy to find.


Along the way we had to share the road with a flock of sheep


Running water! An exciting find for people who walked down a dry creek bed the day before.

We stopped for a short lunch break after making our way down the plateau via the Skyview Drive, and we then made the drive to Mount Nebo on the other side of the valley. Just like on the Wasatch Plateau, we were able to drive through a beautiful national forest as we drove up the slopes. We even ran across features such as Devil’s Kitchen, which seemed very out of place on the forested mountains.

The view from 9000ft in the Wasatch Mountains.

The mini Bryce Canyon...Devil's Kitchen

Once we emerged from the Wasatch Mountains we drove through Nephi to grab something for dinner, and then it was back to Ephraim to prepare for another day in the field.

Final Field Day

June 14th, 2012

FILLMORE, UTAH – [Guest Bloggers Tricia Hall and Will Cary]

We arrived at the field site at 9:30am with the sun already beating down on the lava fields, which are the convenient color of black. Dr. Pollock, Whitney, and Kevin parted with the rest of the group to accumulate more xenolith samples for Kevin’s project. Their group was able to stay close to the cinder cone. This was not the case for the unfortunate followers of Matt Peppers, who had to make long treks across the lava flows.

Team Hot Water (Matt Peppers and followers) started by locating Chubman, the loveable fissure, and set out to track it north. We worked as rapidly as possible in the hope of retiring early from the heat of the day. As we followed the noble Chubman, we found several anastomosing gaping fissures. Some shows some displacement, which was measured by receiving third degree burns from the hot basalt.

Will and Matt measuring the width of the fissure.

Will and Tricia measuring vertical displacement of the fissure, which may indicate a relation with the local fault..

A quick break for lunch under an intense sun left us short of water. We then tried to follow the fissure system to the mapped fault. We ran into an area where basalt debris made it nearly impossible to follow the system farther. We made our way to the fault scarp nearby and measured jointing to help determine the nature of the faulting. After the tracking was done, we quickly measured a monocline along the west margin of the black flow before heading back, our water bottles empty.

Team Hot Water measured these joints along the fault scarp west of the fissure system.

 

 

Team Sandstone (Kevin and followers) travelled around Miter crater attempting to find samples not previously collected.  Kevin began the day with 18 samples and ended with 28 samples, which mean copious amounts of lab work for the young chap. STOP…Hammer time was revamped in an hour-long effort by Kevin Silver to dislodge the xenolith, affectionately named Neopolitan, from the resilient host rock. He did not succeed and resorted to smashing the xenolith with both a hammer and a mallet to analyze the pieces in the lab.

Team Utah wraps up field work for the season.

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