Wooster Geologists in Southwestern Utah (May 2018)

May 25th, 2018

This month, our geological technician Nick Wiesenberg and I had the privilege of taking two Wooster Independent Study students into southwestern Utah to do research on the Carmel Formation (Middle Jurassic). The students were Ethan Killian (’19) on the left and Galen Schwartzberg (’19) on the right. (You’ll get better view of them in the links below where we have blog entries for each day.) I plotted out the localities during a solo expedition last month. We hope we are re-establishing a field area for several more years of work.

This is the local stratigraphic column (modified from that on the Zion National Park website). The area is dominated by the majestic Navajo Sandstone, with our Carmel Formation one of the very few carbonate units.

Our main study areas. 1 = Gunlock region; 2 = Eagle Mountain Ranch; 3 = Dammeron Valley; and 4 = Diamond Valley (“Water Tank”).

Here are links to our daily blog posts —

May 16: Team Jurassic Utah sets to work
May 17: Team Jurassic Utah on the Ranch
May 18: Projects designed, Team Jurassic Utah begins fieldwork
May 19: A day for Jurassic oysters
May 20: Jurassic hardgrounds and Holocene lava flows in southwestern Utah
May 21: Team Jurassic Utah finishes essential data collection
May 22: Zion National Park and life in Santa Clara, Utah
May 23: An oyster ball nursery and Veyo pies on our last field day in SW Utah
May 24: Science and culture on Team Jurassic Utah’s last day

And here are the coordinates of our localities —

N Latitude Longitude Wooster Locality
Location name
37.27875299 -113.78777 C/W-157 C/W157
37.30712598 -113.740137 Eagle MT Road
37.25407499 -113.60516 C/W-751 Water tank
37.308755 -113.73653 C/W-142 Eagle Mtn Ranch cliff
37.27879096 -113.787768 Section base
37.27341698 -113.77961 C/W-752 Double layer DL
37.27298004 -113.778876 C/W-753 Hardground East
37.27855903 -113.787448 C/W-754 Hardground West HW
37.28063799 -113.80023 C/W-755 HFW Hardground
37.27056798 -113.776038 C/W-156 Nursery

Update: Nick heroically drove our samples back to our Wooster paleontology lab. What treasures there are in these three boxes!

Science and culture on Team Jurassic Utah’s last day

May 24th, 2018

Santa Clara, Utah — We spent our last full day in this beautiful state enjoying nature, visiting local historical sites, and ending with a fantastic museum. This morning began with a short journey through Snow Canyon State Park, which is just up the road from Santa Clara. This is a miniature Zion with the same Navajo sandstone, mostly white at the top and red below. The morning light was perfect. Note Nick on the rocks above!

Image by Galen.

Here is an example of the lower red rocks. The foresets on these Jurassic dunes are easy to pick out.

After Snow Canyon we toured the Jacob Hamblin Home in Santa Clara. This house, built in 1862-3, is the oldest surviving structure in Santa Clara. Jacob Hamblin (1819-1886) was a Mormon pioneer with a complicated history but generally known as an honest broker of frontier disputes.

The second floor of the home is a surprisingly large space used as a bedroom for the 11 children and as a community gathering place.

Our final cultural visit was to the St. George Utah Temple of the Latter-day Saints (the Mormons). It is an exquisite structure amidst carefully groomed gardens. We went to the Visitor Center and received a very thorough account of its construction.

Our very last event was suitably paleontological and Jurassic: The Dinosaur Discovery Site at Johnson Farm. This building is constructed over an in situ set of dinosaur trackways in the Moenave Formation (Lower Jurassic).

The tracks are amazingly well preserved and numerous. Above is the dinosaur trace Eubrontes.

Our friend Andrew Milner, Site Paleontologist and Curator, gave us a guided tour, pointing out the extraordinary amount of biological information that can be deduced from trackways.

It is with this wonderful plunge into the world of Early Jurassic terrestrial fauna that our expedition ended. Tomorrow we fly from Las Vegas back to our homes, with Nick driving our precious samples to Wooster. We had a great time. Stay tuned for the laboratory analyses!

An oyster ball nursery and Veyo pies on our last field day in southwestern Utah

May 23rd, 2018

Santa Clara, Utah — When you want to sort out how something grows but can’t actually watch it do it, you look for examples of individuals in various developmental states. You can learn a lot about human growth, for example, by studying a group of people from infants to seniors. We do the same with Jurassic oyster balls: find a diverse population and sort out the relative ages. Today we revisited a site in the Gunlock area which in the 1990s yielded some “baby” oyster balls, thus gaining the name “The Nursery” (C/W-156). On its last day of fieldwork, Team Jurassic Utah (specifically Ethan) found the wonderful array of young oyster balls shown above, from least-developed on the right to most-developed on the left. These will be most useful in our lab analyses this fall.

Here is our last field view of the Gunlock outcrops, mostly the Double Layer (DL) locality. One of our landmarks, Square Top Mountain, rises in the background.

And the last image of Team Jurassic Utah at work. Thanks, Nick.

As we passed through the village of Gunlock, we gave Jay Leavitt two nearly-spherical oyster balls as gifts for him and Judy. They were essential to us for access to private lands, and we had great conversations. The equally generous Hyrum and Gail Smith also received oyster ball presents. I hope they realize what treasures these are. Jay looks a bit dubious!

While in Gunlock we had permission to visit the backyard of a well-known collector, now deceased, who had a pile of oyster balls. Turned out the astounding petrified wood collection dwarfed any we had ever seen!

We had lunch at the famous bakery in tiny Veyo that produces delicious pies.

Beef pot pie followed by strawberry-rhubarb pie. Yum!

Unfortunately we’re going to miss the Utah UFO Festival this weekend in nearby Cedar City! I so would be going.

Our very last fieldwork in the afternoon was anticlimactic. We climbed over this huge exposure of Carmel Formation in Dammeron Valley looking for our holy trinity: oyster balls, hardgrounds, encrusted shells. We found none of these. At least it’s one place to scratch off the paleo list. Lots of potential here for sed/strat projects, though.

Team Jurassic Utah 2018 is done with fieldwork. Tomorrow will be spent visiting local areas of interest, and then we fly out of Las Vegas on Friday.

Zion National Park and life in Santa Clara, Utah

May 22nd, 2018

Santa Clara, Utah — Visiting Zion National Park is an obvious activity for Team Jurassic Utah, considering it is made of beautiful Jurassic rocks. We took the opportunity today. Well, half of the team. Galen and I weren’t feeling well, so Nick took Ethan to the magnificent place. Here they are at The Narrows, with some random people above watching. They had a great time as Galen and I recovered quickly enough back at the base.

Speaking of our base, I should describe it. Our place in Santa Clara is embarrassingly luxurious. I’m forbidden from camping out in southern Utah (an incident with gnat bites and anaphylaxis about 20 years ago!), so I usually stay in motels. Our administrative coordinator Patrice Reeder had a great idea: why not look into Airbnb rentals in the area? She found one on our main route to Gunlock. It is indicated by the red pin above near the southern end of the Santa Clara lava field. Appropriately, this place is called Lava Falls at Entrada. It is significantly cheaper than motel rooms, and much more roomy and private. We’ve also saved on food as Nick, Galen and Ethan are avid (and skilled) cooks.

Here is our own Lava Falls #8 house. The attached garage makes it even more convenient for storing gear and specimens, and for loading and unloading the vehicle.

As you saw from the aerial image, this development is in the lava field, remnants of which surround us. For geologists, this has been a very convenient, comfortable and efficient place to stay. Great idea, Patrice.

Nick brought his mountain bike on the trip, which has been highly useful in the field because he can go off on scouting trips and cover a lot of territory. He also likes to ride the trails at night because of the cool air and lack of other people. Last night he met up with a fox and got this great picture.


Team Jurassic Utah finishes essential data collection

May 21st, 2018

Santa Clara, Utah — A dull but direct title. Every Independent Study advisor knows this critical point in the process: when your students have collected the data necessary to actually do their projects. With discovery-based science like ours on this expedition, you never know what incidents or vagaries in the field will occur before minimum data is acquired. We reached that point today for Galen and Ethan. The final three field days now are gravy!

We started at a very familiar site: Eagle Mountain Ranch (EMR), its iconic cliff is shown above. (Thank you again, ranch owners Hyrum and Gail Smith.) We collected here encrusted and bored bivalve shells from the Carmel Formation exposed on the steep slopes. Most shells had to be pounded out of the rock with hammers and chisels, so it was briefly a noisy place. We did very well, finding bryozoans, encrusting bivalves, sabellids, and a variety of borings, from what I could tell with my hand lens. The full glories of the specimens will be known after we wash them up and examine them with our lab microscopes.

You may just be able to make out Galen in this view. I’m used to standing for hours on steep hillsides bending over to pick up fossils, but it is getting harder!

Below our fossiliferous units at the Eagle Mountain Ranch are thick “books” of thin-bedded carbonates with beautiful mudcracks. An effect of the repeated hexagonal cracks is that the unit itself develops columnar joints, analogous to those often seen in basalt flows. This is a sedimentary version.

Our site at Diamond Valley is where a large water tank was erected, so we call it WT. The excavation exposed a very fossiliferous layer of the Carmel Formation, and many of the calcitic shells are encrusted and bored.

Like this bryozoan-rich bivalve I collected here last month. It is spectacular, especially considering how rare bryozoans are in the Jurassic of North America.

Ethan manned the chisel today.

Galen gathered specimens from the fossiliferous talus. The team made several important finds, ensuring the happy Galen she’ll have plenty of sclerobiont fossils to analyze for the next year of research. Ethan finished his ostreolith collecting yesterday. Field success!

Jurassic hardgrounds and Holocene lava flows in southwestern Utah

May 20th, 2018

Santa Clara, Utah — Team Jurassic Utah spent the day on Galen Schwartzberg’s Independent Study project, the sclerobionts of the Carmel Formation. We began with the above carbonate hardground at the appropriately named Hardground West (HW) locality. (Just a few meters south of C/W-157 and Ethan Killian’s oyster balls; 14.9 meters stratigraphically below them.) A carbonate hardground is a synsedimentarily-cemented seafloor. Above the ruler can be seen the top layer of this hardground with many round holes. They are bivalve borings called Gastrochaenolites. They are what tell us that this was a rocky surface exposed to marine life. Below the ruler the top layer has been removed, revealing that the limestone beneath is full of internal molds of aragonite-shelled bivalves. The aragonite likely dissolved early in the diagenetic process. Did this aragonite then provide the calcium carbonate to cement the layer above? Maybe, but we haven’t yet come up with a test of this hypothesis.

Here Galen is inspecting a hardground. Note that she knows how to protect herself from the relentless sunlight!

One of our hardgrounds with truncated borings. There is an interesting cluster pattern here.

Encrusting organisms that require hard substrates are another identifying feature of hardgrounds. Here our friends the oysters Liostrea strigilecula are attached to a hardground. These are left valves with the right valves removed.

At the end of the day we stopped to walk around the remarkably fresh lava flows near where we’re staying in Santa Clara. These are part of the large Santa Clara Lava Field, which extends from the north rim of the Grand Canyon in Arizona northwards to Fillmore in central Utah. The flows in this area are as young as 32,000 years old. Above Nick and Galen are standing on a pressure ridge.

There are numerous large lava tubes in this volcanic field. Nick and Ethan stand near a large one with a collapsed roof.

Nick made this image. The flows are very difficult to navigate, so I gained new respect for lava hoppers.

This Google Earth image shows the black lava flows near the Airbnb we are inhabiting (the red pin). Urban growth of Santa Clara is eating away at the basalt. Our home here is called, in fact, “Lava Falls”.

A day for Jurassic oysters

May 19th, 2018

Santa Clara, Utah — Team Jurassic worked almost entirely on the oyster ball project today in the Gunlock region. First the students measured the three primary dimensions of several dozen oyster balls (ostreoliths) at the C/W-157 locality (the left side of this valley), and then we followed that road across the slopes to our “Double Layer” (DL) locality in the middle distance. Nick took this image looking southeast.

Ethan (on the left) and Galen are measuring oyster balls in the upper of two layers at the (not surprisingly named) Double Layer locality. We use orange surveyor’s tape to mark our sections and items of interest before collecting data.

The large oyster balls in the lower layer sometimes had to be dug out of the ground.

Here are some of the giant oyster balls. They are flattened, but still have oysters on the undersides as well as across the top surfaces.

A nice giant oyster ball. These might also be termed small oyster reefs.

We also collected some encrusted hardground slabs the students had found at the DL site on an earlier visit. There are oysters on both sides of these slabs, meaning they were undercut on the seafloor or overturned. Either way, they show early cementation on the seafloor.

Nick took this image of the team finishing lunch under the welcome branches of a pinyon pine. Nick did great work for us today by carrying out specimens and scouting new localities as we tediously accumulated data.

We ended the field day with a brief stop to admire the Navajo Sandstone south of the Gunlock Reservoir. What a gorgeous place for geologists!

Projects designed, Team Jurassic Utah begins fieldwork

May 18th, 2018

Santa Clara, Utah — Galen Schwartzberg (’19) and Ethan Killian (’19) now have their specific Senior Independent Study topics, and so today we began to collect data and specimens. This is always a special time because students have so many possibilities they must narrow down to testable hypotheses that we can practically pursue. Galen is now working on the sclerobionts (hard substrate dwelling organisms) of the Carmel Formation (Middle Jurassic) to compare them to global equivalents, and Ethan is looking at the distribution, shape and size variations, and construction of ostreoliths (“oyster balls”).

Our day began with a delightful meeting in Gunlock. Jay Leavitt (in the overalls) and Judy Leavitt (in red) showed us many local rocks and fossils, and helped us navigate the ownership of the land in our study area. They had great stories about life in Gunlock, and many observations of the local geology. They own and operate a gravel pit, so rocks are a way of life for them. They were very generous with permissions and advice. We hope to see them again on this expedition. (Photo by Nick.)

Ostreoliths and their stratigraphic contexts were the main research topics today in the field. Within a few minutes of arriving at our primary ostreolith site near Gunlock (C/W-157), Nick found these four oyster balls nicely lined up in an outcrop. These are in situ, meaning they are in place in the rocks, not rolled down the slopes like most oyster balls in the field. This meant we could plot out the single horizon of ostreoliths and place it in a stratigraphic column. Nick saved us much work by finding the critical exposure right away. (One, I must add, I walked by without seeing many times.)

The terrain is a bit difficult for stratigraphic description (or I’m getting more wobbly on steep slopes), but we set to work making a column. Here I’m showing how to measure a section with a Jacob’s staff (the striped pole behind me). This section has significant covered parts, so we used the contact with the overlying Iron Springs Formation as our datum. The beautiful yellow-red limestone behind us is designated 157-2. (Photo by Nick.)

Here is the stratigraphic section. Ethan (the student standing lowest on the slope) is at the ostreolith horizon. The thick conglomerate at the top is the Iron Springs Formation base.

Here’s a close view of the cross-bedded limestone unit 157-2. The Jacob’s staff is divided into 10 cm intervals. (Photo by Galen.)

That resistant limestone now known as unit 157-2 has the best trace fossils and ripplemarks in the Carmel, and it is less than a meter thick.

At the end of the day Ethan and Galen began measuring the primary dimensions of the oyster balls, starting at the western end of our sampled horizon and working east. This way they not only will have lots of size data, they can see if there is a gradient of shape and size change. Stay tuned for results.

A Folklore Footnote: Jay Leavitt showed us these flattened limestone clasts that erode out of the Iron Springs Formation basal conglomerate in the Gunlock area. He said that as kids he and his friends called them “Devil’s Dollars”, which they believed had “dark and mysterious powers”. This must be a universal childhood legend that takes many forms. For me the currency was old tiles carefully excavated from a dump in my hometown. Jay told us what Devil’s Dollars were really good for — skipping across ponds!

Team Jurassic Utah on the Ranch

May 17th, 2018

Santa Clara, Utah — We were fortunate today to work on the land of Eagle Mountain Ranch just north of Gunlock, Utah. The owners, Hyrum and Gail Smith, met us in the morning in their gorgeous ranch home (shown most effectively in this flyover video) and generously gave us permission to explore the Carmel Formation on their extensive properties. The above outcrop of Carmel Formation topped by the Iron Springs Formation is the most dramatic exposure. We spent most of our time on it. (Preliminary location tag EMR.)

This is a screen capture from the video describing the Eagle Mountain Ranch. Spectacular, and they have Airbnb accommodations! The white rocks in the upper left are Carmel.

Gail Smith guided us on the ranch roads to reach our outcrops. Very kind of her.

Galen at work chipping away at fossils on Eagle Mountain Ranch Cliff, as we call it. Photo by Nick.

This location has fantastic ooids which weather in slight relief, producing these exquisite bedding plane slabs.

The trace fossils here stand out with their granular surfaces of ooids. This is the bottom of the bed, thus hyporelief.

Ethan found this example of Lockeia, a bivalve escape trace, preserved again as convex hyporelief (on the bottom of the bed). This specimen is cool because it is festooned with the star-shaped colmnals of Isocrinus.

We found this hardground at the Eagle Mountain Ranch Cliff locality. The whitish encrusters are the bivalves Plicatula.

Twisty wormtubes are common on bivalve shell fragments. I don’t think these have been described.

This is one of the few places where the actual contact between the Carmel Formation (Middle Jurassic) and Iron Springs Formation (Late Cretaceous) is visible. It is a disconformity with a considerable hiatus (interval of time not recorded, up to 100 million years in this case).

Team Jurassic Utah walking back to the vehicle, with the white Carmel Formation in the background. It was a good day thanks to ranch owners Hyrum and Gail Smith. (Photo by Nick.)

Tomorrow the students begin their individual projects!

Team Jurassic Utah sets to work

May 16th, 2018

Santa Clara, Utah — Team Jurassic Utah had its first day in the field, and it was excellent. As you might recall from this blog, last month I visited southwestern Utah alone to scout out locations for this crew, and today we began work. On the left is Galen Schwartzberg (’19), in the middle is Ethan Killian (’19), and on the right is our geological technician Nick Wiesenberg. They are at Gunlock Reservoir with the delicious Middle Jurassic Carmel Formation exposed in the background. Note the beautiful blue sky. Perfect geology weather.

Classic professorial pointing at Gunlock Reservoir. Photo by Nick.

This is the familiar southwestern Utah stratigraphic column, modified after the column on the Zion National Park website.

We spent the morning exploring the Carmel exposures around Gunlock. At this point we’re doing orientation and working on observation skills. The students proved to be quick studies with the stratigraphy and paleontology, adding already new ideas and information about the Carmel fossils. No one can resist the fascinating oyster balls of the Carmel (officially they are ostreoliths), so Nick, Ethan and Galen found new horizons and worked out a rough stratigraphy of their occurrence. In some places they are so common they’re stacked up. We noted a pattern of shape distribution (spherical vs. flattened), and that the large ostreoliths (up to 75 cm in diameter) seem quite different in origin from the more numerous small ones like those shown above.

Here we were able to determine that the large ostreoliths are consistently stratigraphically below the small ones, and there are subtle changes in sediment color enabling us to predict their distribution. It is 12.6 meters from the large to the small ostreoliths, stratigraphically, and 16.9 meters from the small ostreoliths to the base of the Iron Springs Formation.

The team tramping through the Gunlock region. Note the landmark conical Veyo cinder cone in the background. Photo by Nick.

The Gunlock area we examined in the morning is #1 on the above image. We then drove north through Gunlock to Veyo (top of the image) and turned south on Utah Hwy 18 past the extending Carmel outcrops in Dammeron Valley (#2) to work in the Carmel in suburban Diamond Valley (#3). There we found many shelly fossils, mostly bivalves and crinoids, and numerous tiny encrusters and borings.

I ended the day by giving a presentation to the SW Chapter of the Utah Friends of Paleontology at Dixie State University. I talked about the origin of oyster balls, oddly enough, and what they tell us about the paleoenvironments of the Middle Jurassic in southwestern Utah. It was a fun and inquisitive group with excellent questions and ideas about some of the remaining oyster ball puzzles.


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