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Last day of fieldwork for Team Jurassic Utah 2019

March 17th, 2019

Hurricane, Utah — Our expedition had its final official fieldwork today, which we marked with a group photo overlooking the magnificent Snow Canyon. See the end of this post for alternative flag group images!

Tomorrow the group visits Zion National Park. The next day will be spent exploring the local geology and culture, and then it is packing up our samples for shipment to Wooster. Today, though, The Carmel Formation calls one last time!

We returned to the extensive Carmel outcrops in Dammeron Valley, looking at the northernmost extension of the ooid shoal facies. Here is our short shoal section at Dammeron Valley North (DVN), which consists entirely of cross-bedded limestones placed in four subunits (A-D).

This exposure weathered into many loose slabs from the upper subunit D. The trace fossils are well preserved, including this Planolites with rare branching. It is convex hyporelief.

The traces here include a sinuous bilobed Gyrochorte and a thick trace in the left foreground I can’t yet identify. Anna found this rippled slab.

This big trace Evan found is almost certainly Rhizocorallium.

We originally thought that our section today (DVN) was an extension 638 meters to the west of the DV shoal unit. Nick and Shelley did excellent stratigraphic detective work to show that DVN is about 15 meters below the DV measured unit. We thus found the eastern equivalent of DVN at the DV location, measured and sampled it. For now we call it “DVN at DV”. More detail than anyone wants to know, but these blog entries are also a kind of field notes!

The traditional Wooster flag group photo as taken by Shelley.

The flag group photo taken by Nick.

East of Zion

March 16th, 2019

Hurricane, Utah — Today Team Jurassic Utah traveled to Mt. Carmel Junction, east of Zion National Park, to examine the extensive outcrops of the Carmel Formation in the region. The most famous location is in Mt. Carmel Junction itself (MCJ: N 37.22521°, W 112.68095°). It is this crinoid-rich limestone that is reported to be the youngest encrinite in the geological record.

Anna and I measured a two-meter column in this unit to collect samples for thin-section analysis. Four subunits (A-D) start at the bottom of the ruler here.

This is the base of subunit D. It is full of the star-shaped columnals of the crinoid Isocrinus nicoleti. It is one of only three Jurassic crinoid species in North America.

Fieldwork! Love it. Photo by Nick.

Shelley again measured cross-beds to determine current directions here. This was a complicated task because at least three joint sets intersect in these rocks.

Lunch along the Virgin River. Photo by Nick.

After lunch we went just a bit south of Mt. Carmel Junction to examine a Carmel Formation outcrop that looked superficially like it would be identical to the previous unit. We call the place Carmel Cove (CC: N 37.21548°, W 112.68215°). Turns out the limestone here is very different: no crinoids, no ooids, and relatively abundant bivalves. Amazing variability in sections within sight of each other.

 

Fieldwork continues for Team Jurassic Utah, plus a museum visit

March 15th, 2019

Hurricane, Utah — Every day is a little warmer. Today the team worked on a long section of the Carmel Formation in Dammeron Valley (locality DV: N 37.27629°, W 113.63712°). It is a complete section oof the Co-Op Creek Limestone Member, from its lower contact with the Temple Cap Formation to its upper contact with the Crystal Creek Member.

Our objective was to find the same oolitic unit we measured and sampled at the Water Tank Road (WTR) locality yesterday. We want to see what facies differences are evident within an ooid shoal over some distance. We found the unit with the help of “Nick’s Sandstone” present as a marker bed about five meters above. The unit is shown above. It still has four parts (A-D), but the A unit at the base has a significant siliciclastic component. This Dammeron Valley (DV) unit is also about half as thick as that at WTR. The DV section is 3.74 km north of the one at WTR.

Shelley explored the unit and found very faint bedding structures, a mix of wave and current ripples. She and Anna again collected data to ascertain current and wave directions.

Shelley and Anna are here measuring current and wave directions. Photo by Nick.

Here is Evan in his field mode. My photo of him yesterday was faceless.

This is the top of the Temple Cap Formation in Dammeron Valley. The Carmel is immediately above. Here you can see the distinctive red siltstones and an interval of gypsum beds at the very top.

It was our pleasure to briefly visit the St. George Dinosaur Discovery site today. This is a fantastic museum and laboratory built over bedding planes of the Moenave Formation (Lower Jurassic) covered with dinosaur tracks and sedimentary structures.

The sediments formed along a shoreline of ancient Lake Dixie, so there is a diverse mix of terretrial and aquatic features.

We mainly wanted to visit with Andrew Milner (on the left), the site paleontologist and curator. He always has good paleontological stories and advice. Today he showed us a tiny but significant ammonite found in the Carmel at the Eagle Mountain Ranch locality. We also looked at various vertebrate fossils being prepared in his lab.

Finally, we need to show our beautiful headquarters for this trip — an Air BnB in Hurricane. Since camping is not possible for us, this turned out to be a surprisingly affordable housing option. The garage alone is a bonus for organizing samples and equipment. We are plenty comfortable here!

A much more pleasant day in southwestern Utah

March 14th, 2019

Hurricane, Utah — This is our morning view to the north from our Team Utah headquarters in Hurricane. The snowy Pine Valley Mountains were especially beautiful as the clouds lifted overnight. Such colors. A much warmer day was ahead of us after our freeze-fest yesterday.

Today we returned to the Water Tank location we briefly visited yesterday. This time we concentrated on this meter-thick set of cross-bedded oolites. We described this little column, took four samples, and named the location WTR (for “water tank road”). The coordinates are: N 37.25500°, W 113.60436°.

Anna is here examining the top of the sequence, which appears to represent an ooid shoal.

A very covered Evan does the same. Today he is not protecting himself from the cold as much as the sun.

Dr. Judge, with Anna’s help, collected measurements of the cross-beds to eventually calculate current flow direction, which will be very interesting.

While on a scouting trip for the team, Nick found this mysterious quartzose sandstone unit 5.4 meters above the WRT oolite. It is very much an oddity in an otherwise carbonate sequence. In some parts the sand is loose enough to later run through the Ro-Tap sieves.

For lunch we went to a favorite Wooster restaurant — Veyo Pies! Very appropriate (and crowded) on Pi Day. Photo by Shelley.

Every time I visit this region I make a pilgrimage to the 1857 Mountain Meadows Massacre site north of Central, Utah, on Highway 18. Today it was snow-covered, which made the place seem even lonelier. Please read the historical account of what happened here.

The rock cairn over the mass grave. Lest we forget.

Team Jurassic Utah endures polar conditions

March 13th, 2019

Hurricane, Utah — Well, maybe not fully polar, but it was very cold and windy in southern Utah today. Our glove-less fingers were numb, and the bitter gusts penetrated our pitiful parkas. We collected some samples but put off measuring columns (which inevitably requires working fingers) for a warmer day.

Our mission, as before, was to find ooid-rich units for Anna and mollusk fossils for Evan. We were at the “Water Tank” locality (C/W-751) of last year. It is our least attractive site, having a blue water tower and all.

The bivalves here are numerous and diverse, but only in a narrow horizon (so far). They are certainly more species-rich than at yesterday’s Eagle Mountain Ranch site.Anna found a cross-bedded ooid-rich limestone along the road to the water tank. We will be back to measure and sample this section in detail.For lunch we went to nearby Snow Canyon State Park, where we hoped it would be a tad warmer. (It was — barely.) The sun was out and the colors vivid. This is the Petrified Dunes walk. All you see here is the glorious Navajo Sandstone (Jurassic — beneath the Temple Cap and Carmel Formations).I was entranced by the Moqui Marbles, a kind of iron oxide concretion that weathers out of the Navajo Sandstone. They accumulate in large numbers on the flat surfaces here.

Nick with Moqui Marbles eroded out of the Navajo.Here are Moqui Marbles in place in cross-beds of the Navajo. (Guess whose legs are the scale.) These concretions are diagenetic, forming in the sandstone long after deposition. You can read the latest ideas on their formation in this Moqui Marbles article.

The cold, cold group in Snow Canyon. Image by Shelley.

A productive first day for Wooster Geologists in Utah

March 12th, 2019

Hurricane, Utah — Team Jurassic Utah 2019 started its fieldwork on a cloudy March day with a bit of a chill and some light rain, but it didn’t rain again and the cooler temperatures were comfortable. We worked on the Eagle Mountain Ranch site (C/W-142) looking for ooids (Anna’s Independent Study project) and mollusks (Evan’s I.S. work). Thank you again to ranch owners Hyrum and Gail Smith for permission to work on this important outcrop. (Photo by Nick Wiesenberg.)

Anna and Evan are here describing a critical meter-thick resistant limestone in an otherwise clay-dominated portion of the Co-Op Creek Limestone Member of the Carmel Formation. We think it represents a normal marine incursion into an otherwise restricted lagoonal environment. This is where most of the fossils and ooids at Location C/W-142 come from.

The base of the unit has these very nice wave ripples indicating shallow water.

Nick and Shelley did excellent work measuring the 39 meters of our Carmel interval. They used a Jacob’s Staff with a Brunton compass attached to account for the rock attitude (strike and dip).

Shelley and Nick are the colored dots at the top of our Eagle Mountain Ranch section. They sampled the top of the Carmel here, finding it to be a brecciated limestone below an unconformity with the overlying Upper Cretaceous Iron Springs Formation. The grey wedge of rock thickening to the left is a mysterious claystone. With the breccia discover, we at least know it is above the Carmel.

The team at lunch overlooking the Eagle Mountain Ranch. The slope seemed much steeper than this! (Photo by Nick.)

I know it doesn’t look like much, but Evan found this internal mold of an ammonite at C/W-142. It is the first I’ve seen in the Carmel. (Later Andrew Milner will show us another ammonite from the same location.)

This is the venter view. Definite ammonite, but unidentifiable beyond this!

On the walk back from our main locality, we examined a laminated micritic part of the Co-Op Creek Limestone Member (Location Strom-mat at N 37.30882°, W 113.73883°). This is just below our main section of interest. (Photo by Nick.)

Anna is photographing close details of this unit.

The laminations are spectacular, apparently representing microbial mats. Another future Independent Study project!

Finally, on our drive back to Hurricane we checked out our access to the classic oyster ball localities on the west side of the Santa Clara River. Here is an image of the bridge last year.

The bridge today! A flood destroyed it last month. No way we’re crossing here. Time to explore other options.

Team Jurassic Utah at the Gunlock Reservoir, with the fantastic Carmel Formation in the background.

Team Jurassic Utah 2019 begins its adventure

March 11th, 2019

Hurricane, Utah — A new crew of Wooster Geologists traveled today to southwestern Utah to explore the marvelous Carmel Formation (Middle Jurassic). We are continuing the work of last year’s team and expanding into new areas. We are five people this time: Dr. Shelley Judge, Evan Shadbolt (’20), Anna Cooke (’20), Nick Wiesenberg (our ace departmental technician), and me. Three of us flew today from Salt Lake City to St. George, Utah, enjoying the spectacular geological scenery from the plane. Above is a view of the Wasatch Range just south of Salt Lake City. Very snowy.

Here is the view as we approach the St. George airport. It is the spectacular Hurricane Monocline of the Moenkopi Formation. No snow down here.

This was the first time any of us had used the new St. George Regional Airport. So, so much better than flying into chaotic Las Vegas and making the long drive to Utah.

Fieldwork begins tomorrow!

Science Olympiad training, fossil events

February 18th, 2019

Wooster, Ohio — I had the pleasure today of assisting with the training of Olympians! The above three students are from Orrville High and Middle Schools, along with their coach the ace geology high school teacher Jim Duxbury. They came to Scovel Hall to see our paleontology collections and learn how to identify dozens of fossil types for competition next month in the Science Olympiad. They were a lot of fun in the lab, asking excellent questions and showing their skills in taxonomy. I hope I helped.

I helped train another Science Olympiad team in the summer of 2013, this one in Israel (above). Hanan Ginat was the coach, and these students were also enthusiastic and knowledgeable.

There are few activities more fun than talking about fossils!

Advice from a Grad Student

February 11th, 2019

I caught up with Wooster Geologist Clara Deck (’17) at the AGU meeting in December. Clara is a grad student who has been doing exciting research on glaciers. I asked her to tell us a little about her research and how her experience at Wooster helped her prepare for grad school. She discovered that her research has called on concepts and skills from Structural Geology and Computer Science. Stories like Clara’s motivated us to design our Geology and Environmental Geoscience majors to be flexible, allowing students to explore their interdisciplinary interests and pursue their passions. We’ve also added computational methods to our curriculum. Thanks, Clara, for the inspiration!

Guest blogger: Clara Deck (’17)

Clara Deck on Jarvis Glacier in the East Alaska Range, August 2018.

As a master’s student at the University of Maine’s School of Earth and Climate Sciences, my research has focused on dynamic processes of Antarctic Ice Shelves. Glacial ice in Antarctica flows outward to sea and creates tabular masses called ice shelves, which are tethered to about 75% of the continent’s coastline. These floating ice shelves are critical to the stability of land-based ice because they keep glaciers from flowing freely into the ocean and contributing to global sea level rise. The Ross Ice Shelf (RIS) is the largest in Antarctica and supports the flow of the West Antarctic Ice Sheet, which contains an ice volume of over three meters of global sea level equivalence if it were to enter the ocean. At the western coastal margin of RIS, ice is continuously dragged along protruding bedrock features and becomes deformed, exhibiting large cracks or rifts over a kilometer in length which can be seen in satellite imagery. If a rift were to propagate across RIS, the ice shelf could break up and allow land ice to flow seaward much more quickly. My thesis work aims to characterize the origin and evolution of rifts on RIS using three-dimensional modeling.

Mapping a crevasse on Jarvis Glacier.

I never expected this, but Structural Geology was one of the most helpful classes at Wooster to help me prepare for my graduate work on glaciers and ice shelves. The same stresses at play in tectonics are important within ice, just on a different temporal and spatial scale. I wish I had known that these processes, ductile and brittle, from the micro- to macro-scale, were also applicable to ice!

Evolution of rifts on the Ross Ice Shelf with ice flow, shown through optical imagery from Landsat 1, Landsat 4, Landsat 7, and Sentinel 2, respectively.

At Wooster I took CSCI 100 and 110, classes in Python and C computing languages. These were helpful to learn basics in computing syntax, but it was a steep learning curve in graduate when using computing for glaciological applications. It would have been really useful to have had some background in modeling and writing code related to geological physical processes. I’ve been excited to hear that some modeling is now incorporated into some courses in the Earth Sciences department. Another surprise when starting my master’s was how much calculus is involved in glaciology. I took calc 1 and 2 at Wooster, but I still had quite a bit to catch up on. For students going into climate change or cryospheric studies, I think learning quantitative analysis is just as important as the qualitative side.

Model of a floating ice tongue showing the differential stress field due to buoyancy force from underlying marine water. Solved using a particle approximation of Navier-Stokes for forces associated with water and finite element analysis for high viscosity ice. This model explores the connection of ice shelf deformation with upstream grounding line processes.

Overall, I feel that Wooster Geology prepared me very well for my graduate studies. Because of Sophomore Research and I.S., I had a lot of experience in independent research, seeking out my own resources, and laying out my own goals and timeline. All those skills have helped me be successful so far, because I’ve found that much more responsibility is put on the student at the graduate level. I’m glad I pursued grad school and I hope to defend my master’s thesis this spring!

Bringing three new Silurian bryozoan species into the world

February 10th, 2019

I love being part of the scientific process of naming new organisms and placing them into the grand narrative that is the history of life. It is a kind of rescue — retrieving species from oblivion by giving them identities. Carolus Linnaeus, the father of taxonomy, said it well:

The first step in wisdom is to know the things themselves; this notion consists in having a true idea of the objects; objects are distinguished and known by classifying them methodically and giving them appropriate names. Therefore, classification and name-giving will be the foundation of our science.

The bryozoans described in this post are from a project led by my very accomplished bryozoologist friend Andrej Ernst at the University of Hamburg, Germany (above). In the summer of 2015, Andrej and I met up with our colleague Carl Brett (University of Cincinnati) to collect bryozoans from the Lower Silurian (Aeronian) of western New York. My fieldwork was supported by a grant from the Luce Fund at The College of Wooster. We had a very productive time and saw much geology and paleontology, as you can see from these August 2015 blog posts. That fieldwork was followed by Andrej’s prodigious lab work with the bryozoans. The results have now appeared in the Journal of Paleontology.

The abstract: Thirteen bryozoan species are described from the Brewer Dock (Hickory Corners) Member of the Reynales Formation (lower Silurian, Aeronian) at the locality Hickory Corners in western New York, USA. Three species are new: trepostomes Homotrypa niagarensis n. sp. and Leioclema adsuetum n. sp. and the rhabdomesine cryptostome Moyerella parva n. sp. Only one species, Hennigopora apta Perry and Hattin, 1960, developed obligatory encrusting colonies whereas the others produced erect ramose colonies of various thicknesses and shapes: cylindrical, branched, and lenticular. Bryozoans display high abundance and richness within the rock. This fauna is characteristic of a moderately agitated environment with a stable substrate. The identified species reveal paleobiogeographic connections to other Silurian localities of New York as well as Ohio and Indiana (USA) and Anticosti (Canada).

The top photo in this post is one of the new bryozoans, the trepostome Homotrypa niagarensis. The images are from Figure 8, with the caption: (2) branch oblique section, holotype SMF 23.470; (3) rock thin section with transverse and oblique sections of branches, holotype SMF 23.472; scale bars are 3 mm and 5 mm respectively.

Above is the new trepostome Leioclema adsuetum. The image is from Figure 10, with the caption: (1) longitudinal section of exozone showing autozooecia, mesozooecia, and acanthostyles, paratype SMF 23.553; scale bar is 0.5 mm.

This is the third new species, the cryptostome Moyerella parva. The images are from Figure 11, with the caption: (3) longitudinal section of a colony segment with a pointed base and widened proximal part showing medial axis and autozooecia, holotype SMF 23.559; (4) tangential section showing autozooecial apertures, tubules, and tectitozooecia, holotype SMF 23.559; scale bars are 0.5 mm and 0.2 mm respectively.

The paper is about more than these new species, of course. There are other bryozoans assessed, and Carl Brett’s stratigraphy section is magnificent and a new resource for the area. The new taxa, though, are worth celebrating by themselves.

Thank you to Andrej and Carl for being such good colleagues. I hope we return to the Silurian of western New York for more work.

Reference:

Ernst, A., Brett, C.E. and Wilson, M.A., 2019. Bryozoan fauna from the Reynales Formation (lower Silurian, Aeronian) of New York, USA. Journal of Paleontology, doi.org/10.1017/jpa.2018.101.

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