Team Utah Takes to the Field

June 26th, 2017

Guest Blogger: Addison Thompson (’20, Pitzer College) writes about our first 3 days of field work.

6.23.17 For the Utah group, the first day in the field was daunting yet rewarding as our intrepid group of young geologists made themselves acquainted with the Ice Springs Volcanic Field.  The Ice Springs Volcanic Field, located in the Black Rock Desert of Utah, is home to many old cinder cone volcanos that currently lay dormant.  In the past the cinder cones were active volcanos, spitting and oozing lava.  The lava flows have since cooled and currently take the form of basaltic rocks spilling out from four primary cinder cones, Miter, Crescent, Pocket and Terrace.

The day began at 7:15am with breakfast, after which foods were divided for lunch, sandwiches were assembled, and packs were equipped and made field ready.  Everything was ready, as was the team and off the Utah group went to the field site, arriving just after 9am.  After days of anticipation, stepping out of the car face to face with what the group had read so many articles and papers about was magical.  In no time, the group  was on their way, climbing up the service road, and eventually up the cinder cone named Miter in order to get a lay of the rocky land.

Team Utah atop the Mitre cinder cone

The terrain comprised uneven, sharp, basaltic rocks and was difficult to traverse, but the group managed.  After climbing Miter, the next move was to follow the presumed Miter lava flow path which eventually emptied into a flat basin, an area interpreted to be where a lava flow once pooled.  A good section of pahoehoe, a ropy formation of a basaltic rock, was quickly identified, and its sample was taken.

Sam Patzkowsky (’20 Franklin and Marshall College and Team Keck member) dislodging a piece of Pahoehoe to be used as a sample.

With the success of the pahoehoe find, it was time for lunch.  Shade was hard to come by, so people did their to take refuge from the incessant beating of the sun.  Water was a must.  After lunch the group split up in the attempt to identify the Mitre/Crescent lava flow boundary, not an easy task.  Regardless of the difficulty, progress was made and we ended the day with promising evidence that could work towards our hypothesis.  After a long first day in the field, morale was high but energy was very low; dinner was a welcomed sight.

6.24.17 Waking up on the second day was a breeze.  The group had a plan in mind and very little was left to chance.  First on the chopping block was a visit to the Carbon-14 dating site followed by accessing the area that is believed to house the Miter/Crescent boundary.  Sadly the Carbon-14 dating site was only accessible by a private road, so that idea was nixed.  Next up was entering the lava flows from the north west side via a rarely traveled dirt access road.  The going was bumpy but eventually the car made it to a suitable stopping point.  The walk to the toes (the extent) of the lava flows was a brief flat jog that took minutes; however, the real challenge began when it became necessary to climb the lava flows in order to press on.   Over the course of the trip, the sharp basaltic rocks have claimed many a causality, so the group favored precision over speed.  In searching for Miter/Crescent boundary evidence, it was impossible to ignore other important geologic occurrences.  One of these interesting being a large boulder, about 8ft. tall, comprised of lava bombs that must have been part of a cinder cone that rode a lava flow to the edge.

Measuring a boulder that was transported to its current location by a lava flow.

This helped give an idea about the power of the flows.  Measurements of the boulder were taken along with photos for reference.

As the group pressed deeper into the flows they began to notice an accumulation of large basaltic slabs sticking out of the ground in all directions and angles.  Dr. Pollock noted that information about these slabs could be important towards our ultimate goal, so slab measurements needed to be taken, twenty in all.  Taking a slab measurement consisted of noting the coordinates of the hunk of rock, its width in centimeters, taking photos of the slab under examination, and lastly noting the size of the vesicles (holes created by the expulsion of gas during the cooling process).

Two members of Team Keck measuring a slab’s width.

The reward was lunch and maybe shade.  Luckily, shade was easier to find than the day before and the group crouched, laid, and sprawled under the angled rocks.  But like all good things, lunch came to an end.  Regardless of the heat, the group was always eager for more field work so they decided to push farther east in search of a boundary that had previously been visible from a birds eye map.  At the boundary, samples were to be taken for geochemistry analysis.  Eventually the boundary was reached and the samples were taken.  After a efficient day in the field it was time to turn around.  Dinner was burgers and everyone went to sleep soon there after.

6.25.17  The third full day in Utah did an excellent of of testing everyones nerves.  A special thanks goes out to Dr. Pollock for her cool disposition in the face of a turbulent situation.  The day began as a normal day does with breakfast, then lunch packing, and finally going over the mission of the day.  The catch was that the back right tire of the car that didn’t want to go along with the plan.  Minutes away from the field site the low tire pressure sign flashed on the dashboard so the group turned around and went to go get air for the noticeably deflated tier.  However the issue was that the tire had a puncture, not that it simply had low pressure.  With the spare now on the car, there was no backup and driving over rocky terrain without a spare tire is a disaster waiting to happen, so the call was made to switch rental cars.  This required Dr. Pollock driving the rental up to the Salt Lake Airport to exchange cars, a two hour trip both ways.  This exchange took a majority of the day so there was sadly no time left for field work.  This was definitely a disappointment, but the group handled it well.  The day was instead spent relaxing, uploading information from the field and doing any other minor housekeeping chores.  Emily Randall (’20 College of Wooster and Team Keck member) created a map locating every coordinate where a sample had been taken.  Finally towards the end of the day a few members went on a hike along an ATV path that wound towards the mountains behind the camp site.

A panoramic taken from the hike.

Although no field work was conducted it was a productive day.

 

A Strong Start to the 2017 Keck Gateway Project

June 22nd, 2017

Guest Blogger: Addison Thompson (’20 Pitzer College and Team Keck Member)

The 2017 Keck Gateway Team.

Amid our first official day at the College of Wooster, spirits were high as we embarked on the five week Keck Gateway Project.  The Gateway Project encompasses two different scientific enquiries which will span three states; Ohio, Utah, and Alaska.  The goal of the project centered in Utah is to determine the age of geologically young lava flows (now igneous rock) in the Ice Springs Volcanic Field of central Utah in order to add another piece to the unsolved puzzle of the Earth’s geologic history.  The goal of the project centered in Alaska aims to gain a better idea of why Cedar trees in Juneau are in decline.  The information gained from the students working in Alaska will help pinpoint specific environmental factors that are adversely affecting ecosystems, trees in particular.  This portion of the project is one week long.

Evidence of a tree core.

Once the data from the Utah and Alaska field sites are complied, both teams will return to the College of Wooster to complete lab tests in order to answer each respective hypothesis. This portion of the project is roughly three weeks long.  The participants of the project also have the opportunity to attend and present the findings of their research at the GSA’s (Geological Society of America) annual conference in Seattle in mid-October.

The first full day of the project was a beautiful one and we dove into the topic material with gusto.  We began at 9am in the geology department which is located in Scovel Hall and had a discussion about the rules of authorship and the details of what mentoring means with Dr. Pollock and Dr. Wiles.  Following that, details for the field work trips (Utah and Alaska) were coordinated and supplies like rock hammers and chisels were evenly distributed.  At that point it was time to break for a much needed lunch.  The Keck group met back at Scovel Hall around 1:30, just in time for a jaunt around the Oak grove led by Dr. Wiles, during which the group cored three trees to determine their age.

The processing of coring trees involves inserting a hollow drill into the tree, then removing the sample of the tree located in the hollow drill.

An excited Team Alaska member extracts her tree core.

The Alaska team will use this method hundreds of times in order to determine the health of trees in a large area.  With the first day complete, our group looks forward to strengthening our bonds and embarking on our geology research.

On the second day, the Utah group and the Alaska group split to their respective labs to discuss the minutia of the trips.

The Utah group examined basaltic rocks from the Black Rock Desert, the location where they will be conducting their fieldwork.

These rocks had previously been dated via two techniques: one being Varnish Microlamination (VML) which aims to date the rocks by measuring the coating on rock surfaces, the other being Cosmogenic Nuclide Dating which measures the accumulation of radioactive isotopes in the surfaces of the lava flows.

Meanwhile the Alaska group learned more about tree coring, a practice they will become very familiar with during their stay in the last frontier.

This concluded our work for the day, and we broke for lunch.  The rest of the day was spent preparing for our arduous journeys to the field sites the following morning.  We went shopping to stock up on various items for the trips.  The day came to a conclusion with a delicious dinner and some frisbee outside Douglas Hall.

Much to their chagrin, the Alaska group was departing the College of Wooster at 4am on the third day.  The Utah group was given a more lenient departure time, 6am, because their destination was 2,113 miles closer to the College.  There were no issues rising bright and early and both groups headed to Cleveland Hopkins Airport with anticipation of the journey ahead of them and slightly weary eyes.  To make matters more interesting for the Alaska group, their travel plans routed them through Dallas Fort Worth…not quite in their desired direction but they were sports nonetheless. And so the day went, a travel day.  The Utah group touched down in Salt Lake City in the mid afternoon and began the two hour drive to the town of Fillmore, only stopping once for a much needed dinner.  Eventually the group made it to their campground and settled in their cozy cabins.  After a long day of travel and two hours lost, a rest is what the doctor ordered.  As of writing this, the Alaska group is currently still in transit to Juneau.  Tomorrow marks the first official day of field work in the Black Rock Desert for the Utah group and there is an excited fervor hanging in the air.  All the tools and measurement devices are prepped and ready to go.

 

 

 

 

Team Utah 2015

August 6th, 2015

Guest bloggers: Julia Franceschi and Mary Reinthal

What do you get when you have zero cloud coverage, 90-degree heat, and a desert? Aside from the start of a bad joke, you get a snippet of the College of Wooster geology’s 2015 expedition to Black Rock desert Utah. It was here that some of the College’s senior geology students—Krysden Schantz, Michael Williams, and Kelli Baxstrom—collected some sunburns and samples for their Senior Independent Studies. These research projects range anywhere from trying to figure out the date of the lava flow to mechanisms of emplacement (e.g., channelized vs. inflated flows). Some of the students that went, however, went because they were able-bodied field assistants who could handle the heat. Geology major Julia Franceschi said this about her field assisting experience:

“Utah was extremely hot and there were some days (and by some days I mean everyday) where 3 liters of water were not enough. But we managed to get a lot of good data, even though my boots took a beating (R.I.P). ”

Chloe Wallace and Julia Franceschi use the Trimble GPS to make cm-scale measurements of the topography.

Chloe Wallace and Julia Franceschi use the Trimble GPS to make cm-scale measurements of the topography.

When the plane finally landed in Salt Lake City, Utah, a 2 ½ hour drive took the crew to Fillmore, the location of their field site. The first day, Friday, started around 11AM, but the crew learned quickly that the earlier they started, the less intense the sun (and heat) was.

Team Utah meeting to distribute equipment and plan the field day.

Team Utah meeting to distribute equipment and plan the field day.

Like for most groups, the first day was devoted as a get-accustomed-to-the-field day, that entailed some reconnaissance and exploration. The rest of the week was spent doing eight hours a day of research and studies. According to Dr. Meagen Pollock, walking on a’a is “nonsense” and more often than not, each day was faced with new challenges. Chloe Wallace and Julia conducted high resolution GPS location and elevation data. Dan Misinay took photographs and helped Krysden conduct transects to record vegetative cover. Michael and Kelli spent most of their days mapping the area and attempting to understand volcanic features. Some days, however, were graced with the occasional snake or rainbow to change up the scenery. It was a successful trip.

One of our lizard friends.

One of our lizard friends.

A snake friend, warming itself in the morning sun. Photo credit: Dan Misinay

A snake friend, warming itself in the morning sun. Photo credit: Dan Misinay

Kelli and Dr. Judge measuring striae.

Kelli and Dr. Judge measuring striae.

Krysden is in her element among the lavas.

Krysden is in her element among the lavas. Photo Credit: Dan Misinay

Contemplating lava emplacement clearly brings joy to Michael.

Contemplating lava emplacement clearly brings joy to Michael. Photo Credit: Dan Misinay

Dan helps Krysden with her vegetation survey.

Dan helps Krysden with her vegetation survey.

We were treated to a double rainbow over our field site after a light sprinkle in the desert.

We were treated to a double rainbow over our field site after a light sprinkle in the desert.

And a show of wild flowers! Photo Credit: Kelli Baxstrom

And a show of wild flowers! Photo Credit: Kelli Baxstrom

Team Utah proudly representing Wooster Geologists!

Team Utah proudly representing Wooster Geologists!

Wooster’s Fossil of the Week: A Middle Jurassic trace fossil from southwestern Utah

April 17th, 2015

1 Gyrochorte 2 CarmelTime for a trace fossil! This is one of my favorite ichnogenera (the trace fossil equivalent of a biological genus). It is Gyrochorte Heer, 1865, from the Middle Jurassic (Bathonian) Carmel Formation of southwestern Utah (near Gunlock; locality C/W-142). It was collected on an Independent Study field trip a long, long time ago with Steve Smail. We are looking at a convex epirelief, meaning the trace is convex to our view (positive) on the top bedding plane. This is how Gyrochorte is usually recognized.
2 Gyroxhorte hyporelief 585A quick confirmation that we are looking at Gyrochorte is provided by turning the specimen over and looking at the bottom of the bed, the hyporelief. We see above a simple double track in concave (negative) hyporelief. Gyrochorte typically penetrates deep in the sediment, generating a trace that penetrates through several layers.
3 Gyrochorte Carmel 040515Gyrochorte is bilobed (two rows of impressions). When the burrowing animal took a hard turn, as above, the impressions separate and show feathery distal ends.
4 Gyrochorte 585Gyrochorte traces can become complex intertwined, and their detailed features can change along the same trace.
5 Gibert Benner fig 1This is a model of Gyrochorte presented by Gibert and Benner (2002, fig. 1). A is a three-dimensional view of the trace, with the top of the bed at the top; B is the morphology of an individual layer; C is the typical preservation of Gyrochorte.

Our Gyrochorte is common in the oobiosparites and grainstones of the Carmel Formation (mostly in Member D). The paleoenvironment here appears to have been shallow ramp shoal and lagoonal. Other trace fossils in these units include Nereites, Asteriacites, Chondrites, Palaeophycus, Monocraterion and Teichichnus.

So what kind of animal produced Gyrochorte? There is no simple answer. The animal burrowed obliquely in a series of small steps. Most researchers attribute this to a deposit-feeder searching through sediments rather poor in organic material. It may have been some kind of annelid worm (always the easiest answer!) or an amphipod-like arthropod. There is no trace like it being produced today.

We have renewed interest in Gyrochorte because a team of Wooster Geologists is going to Scarborough, England, this summer to work in Jurassic sections. One well-known trace fossil there is Gyrochorte (see Powell, 1992).
6 Heer from ScienceOswald Heer (1809-1883) named Gyrochorte in 1865. He was a Swiss naturalist with very diverse interests, from insects to plants to the developing science of trace fossils. Heer was a very productive professor of botany at the University of Zürich. In paleobotany alone he described over 1600 new species. One of his contributions was the observation that the Arctic was not always as cold as it is now and was likely an evolutionary center for the radiation of many European organisms.

References:

Gibert, J.M. de and Benner, J.S. 2002. The trace fossil Gyrochorte: ethology and paleoecology. Revista Espanola de paleontologia 17: 1-12.

Heer, O. 1864-1865. Die Urwelt der Schweiz. 1st edition, Zurich. 622 pp.

Heinberg, C. 1973. The internal structure of the trace fossils Gyrochorte and Curvolithus. Lethaia 6: 227-238.

Karaszewski, W. 1974. Rhizocorallium, Gyrochorte and other trace fossils from the Middle Jurassic of the Inowlódz Region, Middle Poland. Bulletin of the Polish Academy of Sciences 21: 199-204.

Powell, J.H. 1992. Gyrochorte burrows from the Scarborough Formation (Middle Jurassic) of the Cleveland Basin, and their sedimentological setting. Proceedings of the Yorkshire Geological Society 49: 41-47.

Wilson. M.A. 1997. Trace fossils, hardgrounds and ostreoliths in the Carmel Formation (Middle Jurassic) of southwestern Utah. In: Link, P.K. and Kowallis, B.J. (eds.), Mesozoic to Recent Geology of Utah. Brigham Young University Geology Studies 42, part II, p. 6-9.

Wooster’s Fossil of the Week: Star-shaped crinoid columnals from the Middle Jurassic of southern Utah

February 27th, 2015

Isocrinus nicoleti Kane County 585Just a quick Fossil of the Week post. Above we see isolated columnals (stem units) of the crinoid Isocrinus nicoleti (Desor, 1845) found in the Co-Op Creek Member of the Carmel Formation (Middle Jurassic), Kane County, southern Utah. Greg Wiles recently received them as part of a donation to our department collections. They have such perfect star shapes that I had to share them here. For the full analysis, see my previous entry on columnals like these preserved in a limestone from the same location.

References:

Baumiller, T.K., Llewellyn, G., Messing, C.G. and Ausich, W.I. 1995. Taphonomy of isocrinid stalks: influence of decay and autotomy. Palaios 10: 87-95.

Tang, C.M., Bottjer, D.J. and Simms, M.J. 2000. Stalked crinoids from a Jurassic tidal deposit in western North America. Lethaia 33: 46-54.

Wooster’s Fossil of the Week: An early bryozoan on a Middle Ordovician hardground from Utah

October 10th, 2014

ORBIPORA UTAHENSIS (Hinds, 1970) 072014Last week I presented eocrinoid holdfasts on carbonate hardgrounds from the Kanosh Formation (Middle Ordovician) in west-central Utah. This week we have a thick and strangely featureless bryozoan from the same hardgrounds. It is very common on these surfaces, forming gray, perforate masses that look stuck on like silly putty. Above you see one on the left end of this hardground fragment. (The circular object to the right is another eocrinoid holdfast.)
Kanosh bryo eo 072014Here is a closer view of the bryozoan, again with one of those ubiquitous eocrinoids encrusting it. The holes are the zooecial apertures. Each zooecium is the skeletal component of a living bryozoan individual (zooid). Note that the walls are thick and granular between the zooecia. All the zooecia look pretty much the same, and there are no other structures like spines, pillars or maculae. This is about as simple as a bryozoan gets.

It is impossible to be certain without a thin-section or acetate peel showing the interior, but I’m pretty sure this Kanosh bryozoan is Orbipora utahensis (Hinds, 1970). It matches fairly well the description in Hinds (1970), who named it Dianulites utahensis, and it fits within the redescription by Ernst et al. (2007).

Several years ago we would have called this a trepostome bryozoan and left it at that. These are, after all, the “stony bryozoans” with thick calcite skeletons and long zooecia. However, the group to which Orbipora belongs is unusual because they have no polymorphs (small zooecia different from the primary zooecia) and have granular skeletal textures rather than laminated. We think the granular walls may be because the original skeletons were made of high-magnesium calcite that later altered to low-magnesium calcite and dolomite, losing details of the microstructure. Orbipora is thus in an as yet undescribed new order of bryozoans. [Update: See comment below from Paul Taylor.]

The Kanosh hardgrounds and their attaching faunas are important in geological and biological history because they are telling us something about the geochemical conditions of the seawater when they formed. We think this was a peak time of Calcite Seas, when low-magnesium calcite was a primary marine precipitate and carbon dioxide levels were high in the atmosphere and seawater. Hardgrounds would have formed rapidly because of early cementation, and aragonite and high-magnesium skeletons would have altered soon after death. The abundant Kanosh communities and substrates are critical evidence for these conditions that were superimposed on the Great Ordovician Biodiversification Event (GOBE). We thus have a delightful combination of seawater geochemistry (and, ultimately, the tectonics that controls it) and evolution intertwined in the history of these rocks and fossils.

References:

Ernst, A., Taylor, P.D. and Wilson, M.A. 2007. Ordovician bryozoans from the Kanosh Formation (Whiterockian) of Utah, USA. Journal of Paleontology 81: 998-1008.

Hinds, R.W. 1970. Ordovician Bryozoa from the Pogonip Group of Millard County, western Utah. Brigham Young University Research Studies, Geology Series 17: 19–40.

Marenco, P.J., Marenco, K.N., Lubitz, R.L. and Niu, D. 2013. Contrasting long-term global and short-term local redox proxies during the Great Ordovician Biodiversification Event: A case study from Fossil Mountain, Utah, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 377: 45-51.

Wilson, M.A., Palmer, T.J., Guensburg, T.E., Finton, C.D. and Kaufman, L.E. 1992. The development of an Early Ordovician hardground community in response to rapid sea-floor calcite precipitation. Lethaia 25: 19-34.

Wooster’s Fossils of the Week: Eocrinoid holdfasts on a Middle Ordovician hardground from Utah

October 3rd, 2014

Kanosh Hardground 072014 smBack in the late 1980s and early 1990s, several students and I did fieldwork in the Middle Ordovician Kanosh Formation in west-central Utah. One year we were joined by my friend Tim Palmer of the University of Aberystwyth. Together, Chris Finton (’91), Lewis Kaufman (’91), Tim and I put together a paper describing the carbonate hardground communities in this remarkable formation (Wilson et al., 1992). At top is an image of one of the surface of one of these hardgrounds. It is covered with holdfasts of rhipidocystid eocrinoids, a kind of primitive echinoderm.
Fossil Mountain UtahMost of the hardgrounds we studied in the Kanosh Formation were found here at Fossil Mountain near Ibex, Utah. (If you want to consider Ibex a place, at least.) It was a beautiful place to work, and it is still highly productive for geologists and paleontologists (see Marenco et al., 2013, for the latest investigation).

Kanosh eocrinoid 2The encrusters on the Kanosh hardgrounds are dominated by two groups: bryozoans (which we’ll highlight next week) and stemmed echinoderms (this week’s subject). The echinoderms are represented by thousands of these small attachment structures called holdfasts. The stem of the echinoderm was attached here to the hardground. The entire skeleton of the echinoderm, including the hardground, is made of low-magnesium calcite, so they are very well preserved. Surprisingly, the hardground communities in the Kanosh have very few sponges or borings.

Kanosh eocrinoid 3 072014The holdfasts come in a few varieties with subtle morphological differences. Here we have one with a tri-radiate center.

Kanosh eocrinoids 1Sometimes the holdfasts blended together on the hardground surface, which was probably the result of competition for attachment space. Note the tri-radiate centers.

Mandalacystis diagramFrom a few plates we found, it appears that the rhipidocystid eocrinoid holdfasts are from a creature like Mandalacystis, which is pictured above from Figure 1 of Lewis et al. (1987). We can’t tell for certain without more of the skeleton, but the holdfasts are very similar to what has been described for the genus.

These Middle Ordovician hardgrounds were formed at an interesting time in the chemistry of the oceans and the development of marine invertebrate faunas. More on that next week!

References:

Ernst, A., Taylor, P.D. and Wilson, M.A. 2007. Ordovician bryozoans from the Kanosh Formation (Whiterockian) of Utah, USA. Journal of Paleontology 81: 998-1008.

Lewis, R.D., Sprinkle, J., Bailey, J.B., Moffit, J. and Parsley, R.L. 1987. Mandalacystis, a new rhipidocystid eocrinoid from the Whiterockian Stage (Ordovician) in Oklahoma and Nevada. Journal of Paleontology 61: 1222-1235.

Marenco, P.J., Marenco, K.N., Lubitz, R.L. and Niu, D. 2013. Contrasting long-term global and short-term local redox proxies during the Great Ordovician Biodiversification Event: A case study from Fossil Mountain, Utah, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 377: 45-51.

Wilson, M.A., Palmer, T.J., Guensburg, T.E., Finton, C.D. and Kaufman, L.E. 1992. The development of an Early Ordovician hardground community in response to rapid sea-floor calcite precipitation. Lethaia 25: 19-34.

Wooster’s Fossil of the Week: A faulted oyster ball from the Middle Jurassic of Utah

July 25th, 2014

Split oyster ball 062914I’m returning this week to one of my favorite fossil types: the ostreolith, popularly known as the “oyster ball”. These were lovingly described in a previous blog entry, so please click there to see how they were formed and some additional images. They are found almost exclusively in the Carmel Formation (Middle Jurassic) of southwestern Utah.They are circumrotatory (a fancy word for “rolling around while forming”) accumulations of small cup-like oysters along with minor numbers of plicatulid bivalves, disciniscid brachiopods, cyclostome bryozoans (see Taylor & Wilson, 1999), and mytilid bivalves that drilled borings known as Gastrochaenolites. They are nice little hard-substrate communities originally nucleated on bivalve shells (Wilson et al., 1998).

oyster ball close 062914Here is a close view of the oyster valves on the outside of the ostreolith. They are attached to similar valves below them, and it is oysters all the way to the center.

What is special about our specimen here is that it managed to obtain a fault right through its center! The chances of this happening are slim, given that they are relatively rare in the rock matrix. The faulting was probably during the Miocene related to a “left-lateral transfer zone that displaces north-south–trending crustal blocks of the eastern Basin and Range Province to the west” (Petronis et al., 2014, p. 534). This is an interesting tectonic region between the Basin and Range Province and the Colorado Plateau.

Slickenfibers 062914A close view of the fault surface shows it is a striated slickenside. The striations (called slickenlines) are parallel to the direction of movement, not that we have to guess when we look at the ostreolith itself. There are also calcitic deposits here formed during faulting called slickenfibres. These elongated crystals have tiny step-like breaks in them that show the actual direction of movement.

Another nice specimen combining paleontology and structural geology.

References:

Petronis, M.S., Holm, D.K., Geissman, J.W., Hacker, D.B. and Arnold, B.J. 2014. Paleomagnetic results from the eastern Caliente-Enterprise zone, southwestern Utah: Implications for initiation of a major Miocene transfer zone. Geosphere 10: 534-563.

Taylor, P.D. and Wilson, M.A. 1999. Middle Jurassic bryozoans from the Carmel Formation of southwestern Utah. Journal of Paleontology 73: 816-830.

Wilson, M.A., Ozanne, C.R. and Palmer, T.J. 1998. Origin and paleoecology of free-rolling oyster accumulations (ostreoliths) in the Middle Jurassic of southwestern Utah, USA. Palaios 13: 70-78.

Iron Flows and Camera Blows

July 21st, 2014

Guest Bloggers:  Sarah McGrath (’17) and Chloe Wallace (’17), both members of Team Utah 2014

 

EPHRAIM, UTAH — No longer rookie bloggers Chloe and Sarah here, coming at you from the sweet comfort of our couch in Utah. Before collecting pounds of oncolites and encountering countless kill sites, we were just two inexperienced field geologists spending our long days becoming pros with the Trimble. The Trimble is a survey grade GPS unit. We used it to map the many iron concretions throughout the Six-Mile Canyon Formation. Over the course of a day and a half we were able to map over 200 points on one single rib of the outcrop.

As you will see below it takes a truly skilled and brave geologist to be worthy of the power that is the Trimble. Lesson learned: do not forget to zip the pocket that is holding your camera as you lean over a steep cliff just to collect a single data point. Thankfully, Sarah’s camera survived the fall and still works somehow. Nikons, people! Also as Sarah was retrieving her camera she came upon some lovely iron staining that otherwise would not have been discovered. There’s always an upside!

picture 6 - 585

How to Trimble 101: This isn’t your basic car GPS.

picture 7 - 585

Seconds before Sarah dropped her camera down the side of the cliff. All in the name of science!

picture 8 - 585

The iron staining Sarah came upon while retrieving her camera at the bottom of the cliff.

picture 9 - 585

We’ve gotten too used to this view. We’re going to miss Utah! Thanks for an amazing two weeks full of scalding heat, accessibility to more Peace Tea than one human should consume, and unforgettable geology.

 

 

Oncolites and Kill Sites

July 21st, 2014

Guest Bloggers:  Sarah McGrath (’17) and Chloe Wallace (’17), both members of Team Utah 2014

 

EPHRAIM, UTAH —  Rookie bloggers, Sarah and Chloe, coming at you from beautiful Ephraim, Utah! We’ll admit early on that are blogging skills are not the most proficient, but we’re giving it a shot (mostly because we are being “strongly encouraged”). We figure plenty of enticing pictures will make up for what we are lacking.

We began a new project in the field on Thursday. We gathered data and collected oncolites in the North Horn Formation. We measured over 50 oncolites within the rock face and collected about a dozen float samples. The following day we did more oncolite work, collecting at least 150 float samples, in the Flagstaff at “Snake Ridge,” which was cleverly named by Dr. Judge after countless rattlesnake sightings. Luckily for us, we have yet to see a single snake the entire trip. Knock on wood; still one day left in the field.

Although we haven’t seen any rattlesnakes, we’ve encountered enough kill sites to last us a lifetime. At our first sighting we ran away in disgust, but by our most recent kill site we were taking creative photos with them. We suspect our friend Freddy the mountain lion may be at fault.

picture 1 - 585

The view from the North Horn Formation.

picture 2 - 585

One bag out of many of the collected oncolites at the infamous “Snake Ledge.”  Note the medical tape holding one of the oncolites together!!

picture 3 - killsite

Most recent kill site shot. Maggots don’t scare us.

picture 4 - 585

More wildlife encountered in the field. This jackrabbit kept us quite entertained for at least thirty minutes.

picture 5 - 585

Possible homestead of the one and only Freddy the mountain lion.

 

 

Next »