Wooster undergraduate researchers will share findings at international conference

August 2nd, 2019

Wooster, OH – Team Geochemistry finished a highly productive summer research season with two conference abstracts that we submitted to the 2019 Fall Meeting of the American Geophysical Union. AGU will be an excellent opportunity for the team to hone their presentation skills, network with potential employers and graduate school advisors, and explore the wide range of disciplines in the geosciences. Read about our work in the abstracts:

Ok and Bræðravirki offer us opportunities to explore past climates and interactions between volcanoes and glaciers, helping us predict what might be in store for Iceland and other ice-covered volcanoes across the world. (Photo Credit: Hannah Grachen)

A Geochemical Study of Bræðravirki Ridge (Western Volcanic Zone, Iceland) Reveals Regional Glaciovolcanic Variations and Complex Tindar Construction 

By Hannah Grachen, Simon Crawford-Muscat, Billy Irving, Meagen Pollock, Benjamin R. Edwards, Shelley A. Judge, Layali Banna, Kendra Devereux, Marisa Schaefer

Summary: As global ice recedes in response to climate change, volcanoes that erupted under the ice are becoming more exposed. We studied one such subglacial volcano in Iceland called Bræðravirki Ridge, and found that Bræðravirki is chemically different from other nearby subglacial volcanoes. We also found that there were several packages of volcanic ash and lava that were erupted at different times. These findings show that subglacial eruptions are complicated, and we might be able to use these types of observations to understand more about the history of volcanoes and glacial ice in an area.

Although tuyas in the Western Volcanic Zone (WVZ) of Iceland have been studied in detail, little work has been done on the numerous smaller tindars there. This study compares Bræðravirki Ridge, a 3-km long tindar on the southeastern flank of Ok shield volcano in the WVZ, to regional tuyas and creates a model for ridge formation based on combined mapping and geochemical analyses. Bræðravirki is dominated by palagonitized lapilli tuff with scattered intrusions, rare exposures of intact pillow lavas, and multiple tuff/lapilli tuff units. Whole rock samples were measured for major and trace elements by XRF and ICP-MS. Mineral compositions were measured by SEM-EDS. Major elements show that Bræðravirki is relatively enriched in SiO2 and depleted in CaO, FeO*, and MgO compared to regional data. Within the ridge, vitric tuff/lapilli tuff units are more evolved (MgO 6.29-6.66 wt.%) than other units (MgO 6.94-7.72 wt.%). Preliminary Rhyolite-MELTS (v. 1.0.1) models are consistent with the two compositional groups being genetically related by 3 kb fractional crystallization of a common parent magma. The MELTS models generate plagioclase (An61 to An70) and two pyroxene (low- and high-Ca) compositions that are observed in the SEM-EDS mineral data. Incompatible trace elements show limited variation between the two compositional groups (Nb/Y 0.37-0.41), suggesting stable melting conditions. We propose a two-stage eruptive model that begins with an explosive phase, followed by a second explosive-effusive phase that forms intrusions and pillows. The second phase is hypothesized to be initiated by a recharge event, emplacing the higher-MgO units. This study demonstrates that small tindars can be constructed through multiple eruptive events that shift in eruptive style and that glaciovolcanic edifices in the same region can have significant compositional differences, possibly providing insights into the understanding of their timing, magmatic history, and paleo-ice conditions.

Microscope photo of one of the granitic rock samples that was classified using the new and old naming systems.

New Igneous Classification System Produces Consistent Rock Names and Illuminates Modal Data

By Hannah Grachen, Anna Cooke, Charley Hankla, Ethan Killian, Cody Park, Layali Banna, Kendra Devereux, Meagen Pollock

Summary: Rock names are useful for understanding what a rock is made of, how it formed, and how it might be useful. For rocks that form from molten magma, the current naming system doesn’t communicate all of the relevant information. Earlier this year, scientists proposed a controversial new naming system to make rock names more meaningful. We tested the new naming system and found that it worked well at the microscopic scale but was more confusing when using the naked eye. We found that the new rock names contained more useful information than the old rock names, and we think that the new system could become the future of rock classification.

In the February 2019 issue of GSA Today, Glazner et al. proposed a new classification system for igneous rocks, citing shortcomings within the standard International Union of Geological Sciences (IUGS) classification system, in use since 1974; chiefly its inability to convey modal data and its arbitrary division of interrelated rocks into disparate types. Their proposed system recognizes rock classifications on ternary diagrams to be “fuzzy” rather than distinct, therefore better representing the continuous nature of rock sequences and lending their system the term “fuzzy classification scheme”. They suggest a system of limited root names combined with modal percentage numbers and significant accessory minerals to provide more informative and straightforward rock names. To test this claim, we have named a suite of six thin sections and hand samples of granitic rocks from Songo Pluton, North Jay Quarry, Mount Waldo, and Deer Isle, using both the IUGS and “fuzzy” classification schemes. We also obtained modes on thin sections through quantitative image analysis using Adobe Illustrator and ImageJ, this being an important step in our process due to the difficulty of differentiating alkali feldspar and plagioclase in our samples. We determined that while the comments on Glazner et al.’s paper are critical, in the tests we performed, some of those criticisms, such as the non-replicability of the proposed system due to interpretive bias, are insubstantial. In thin section, the fuzzy system naming led to more consistent naming results than in hand sample observations, while the opposite was true in hand sample. One of the things we would suggest after conducting our tests is to include boundaries to distinguish the names in a better way. Overall, the proposed system’s ease of data communication is an improvement on the IUGS system that warrants more attention and modification.

Wooster geologists working at site of first glacier memorial in Iceland

July 23rd, 2019

Iceland – Big news this week as researchers dedicate the first-ever monument to Okjökull glacier, memorializing the first Icelandic glacier to lose its glacier status to climate change. Ice loss in Iceland is dramatic; researchers expect all of Iceland’s glaciers to go extinct in the next ~200 years, with drastic changes to Icelandic culture and economy. As the ice retreats and reveals the underlying land, scientists can investigate ancient volcanoes that erupted thousands of years ago under the glacier. Wooster geologists were with a team from Dickinson College on the scene of Ok volcano this summer, exploring a glaciovolcanic ridge that is now exposed on the southeast flank of Ok volcano.

View of Ok shield volcano from the south. Bræðravirki is the glaciovolcanic ridge on the southeast flank of Ok volcano. (Photo Credit: Hannah Grachen)

Another view of Bræðravirki ridge from the east. The summit of Ok volcano is off of the photo to the right. (Photo Credit: Hannah Grachen)

Most of Bræðravirki ridge is made of yellow ash that was erupted explosively and has been consolidated into a rock called tuff. The patterns in the rock tell us about how it formed. (Photo Credit: Hannah Grachen)

The tuff has a distinct yellow color that forms when the volcanic ash reacts with hot water. We also see glassy black rocks in the ash that we think are volcanic bombs, which form when lava is ejected violently during an explosive eruption. (Photo Credit: Hannah Grachen)

The ridge also has irregularly shaped bodies of massive rock. These are light gray and extremely hard, with a unique pattern of cracks that forms as the molten rock cools and solidifies. We think these are fingers of magma that get injected into the growing ash pile. (Photo Credit: Hannah Grachen)

Ok volcano and Bræðravirki ridge give us the opportunity to explore past climates and interactions between volcanoes and glaciers, helping us predict what might be in store for Iceland and other ice-covered volcanoes across the world. (Photo Credit: Hannah Grachen)

Look for us at the December 2019 meeting of the American Geophysical Union in San Francisco, CA (USA), where we will be presenting our findings from Bræðravirki ridge.

Summer undergraduate researchers travel to Iceland to explore volcanoes

July 19th, 2019

Iceland – In our last post, Team Geochemistry was getting ready to head to Iceland for some field work on volcanoes. Our goals were to map and sample volcanoes that erupted under glaciers, which have since retreated, exposing the pillow lavas and ash that formed when lava met ice. We met up with a research team from the Dickinson College Earth Sciences Department, and also brought Dr. Shelley Judge, Wooster’s structural geologist. Together, we collected over 30 samples, took 1000s of photos, flew the drone for 8 hours, and made 100s of structural measurements. Overall, it was a successful and productive field season, with some laughs along the way! Layali Banna, member of Team Geochemistry (and basalt goddess), describes their field experience.

[Guest blogger Layali Banna] Last week, team geochemistry went to Iceland. We met up with some old friends there, but we met some new ones as well. In total there were ten of us and we were ready to take Iceland by storm.

All of us walking along Undirhlíðar (from left to right: Phoebe, Dr. Edwards, Marisa, Dr. Judge, Dr. Pollock, Kendra, Layali and Ethan; Hannah Is behind the camera taking the photo.)

After a long day of flying we decided to mostly take it easy, just doing a short walk around a nearby quarry to learn more about what we will be looking for out in the field.

Dr. Pollock posing for her glamour shot.

The second day was much different though – we spent almost all day out on Hannah’s site collecting samples for her project at Bræðravirki ridge. Divided into two teams, one group walked the ridge collecting samples, while the other group used a drone to map the ridge. This was a prime time up at the ridge since there was no snow cover, unlike past years where the gullies were hidden by snow, allowing us a great look at it without anything in the way.

Kendra smiling with Prestahnúkur in the background, which is a rhyolite volcano.

A gulley on Bræðravirki that was buried in snow during past years was now accessible for sampling.

Our third day in Iceland after that long day in Bræðravirki we spent the morning inside working on our field books and collecting some data, making observations on our samples.

 

Everyone working together to look through all the samples we had collected the day prior.

The latter half of the day we surveyed Undirhlíðar and ended up goofing around a bit at a certain spot called the bowl.

Kendra and Marisa trying to figure out how they are going to climb up the side of the bowl.

After our half day we returned to Undirhlíðar. This time we were split up into three groups all doing different things in separate areas. One group mapped with drones, another analyzed and mapped deformation bands, taking samples and pictures of the bands, and the last group went and took samples for Marisa’s project.

A beautiful, thick, glassy dike found on Undirhlíðar.

Time for a snack break! Marisa is eating a nutritious energy boosting cookie.

Finally, on our last day in Iceland everyone was given a free day to do what they want, exploring some of the natural wonders the island has to offer as well as touring the capital of Iceland, ReykjavÍk.

Hannah finally getting her photo taken instead of her always being the one taking them at Krýsuvík thermal zone.

The group stopped for some famous Icelandic street dogs in ReykjavÍk, Kendra is ready to dig in.

All too soon it was time for us to pack our bags and say goodbye to our friends and Iceland. It was time to head back to Wooster and work on the samples we collected in the lab.

 

The week leading up to international field work

July 6th, 2019

Wooster, OH – In the week leading up to field work, Team Geochemistry was frantically trying to “put out fires” and clean up loose-ends.

The “fires” started first thing Monday morning, when a leak in the geochemistry lab caused the ceiling to collapse. Fortunately, the students and cleaning staff were quick thinking and all ended well.

Next, we tried to wrap up our petrology classification project, which involved lots of microscope work. Classifying minerals in the microscope was more challenging than we expected, and we still have more work to do when we return from the field.

Finally, we had to gather our field gear, double-checking that we had everything we needed. Undoubtedly, there will be something that we forgot.

Even with the frantic pace of the week, we still made some time for an ice cream (or two!). It was the Fourth of July holiday, after all.

Team Geochemistry in currently en route to Iceland for some field work. We’ll be reunited with Marisa, our teammate from Dickinson College, along with Dr. Ben Edwards and three other Dickinson students. Dr. Shelley Judge, from Wooster, is also joining us for this field excursion. Look for updates from the field late next week!

Summer research from an undergraduate perspective

June 29th, 2019

Wooster, OH – While Dr. Pollock was away at a business meeting for the Council on Undergraduate Research, Team Geochemistry was hard at work in the Wooster X-ray lab. Here’s what they thought about last week:

This week, team geochemistry was left without Dr. Pollock for a few days, but that didn’t stop them from getting lots done! Layali and Kendra have been hard at work processing the results from last week’s full XRF run. They compared the results of standards and the accuracy of a few different programs to make sure the instrument is calibrated correctly. They are hoping to understand why their previous run gave some surprising results. 

Layali looking through some trace element data.

Hannah has been continuing to prepare her samples, working hard to polish volcanic glass that she will send off to Oberlin College for analysis using a scanning electron microscope (SEM-EDS). She has also been taking pictures of and looking at thin sections of her samples, hoping to understand more about their composition.

Hannah viewing the photos she took of her thin sections.

This week marks the halfway point of the team’s project. Having spent the majority of that time living on campus, the team has some insights on what it’s like to be here during the summer and what it’s like working on their project:

We all agree that it is much different than being on campus during the academic year – there are far fewer students around and much less to do on campus. It can get a little boring being here because it’s easy to fall in to a routine – go to work, eat, watch TV, sleep, and then wake up to do it again. We have found it necessary to find activities to break up this cycle, including hikes at a nearby park, excursions for bubble tea and Sheetz, board games, and movie nights. We have become great friends over these few weeks and have found that doing things together outside of work makes living on campus much more fun. It is best to have a car on campus (or to befriend someone who has a car) so that you can get out and find things to do. However, it is also quite easy to walk downtown to go to some shops or restaurants, so even without a car, there is a lot to do.

Simply working on this project is also something that is very different for all of us. We aren’t used to working 8 hours a day, 5 days a week. Being stuck in the lab can be really tiring, so we have found that taking breaks to play games or to take a walk around campus really help us stay awake and productive. We are learning lots of new skills, meaning it’s very important to stay focused and attentive so that we can get the most out of this wonderful experience. We can’t believe that we are halfway through our time here this summer!

 

Hands-on experience troubleshooting geochemical instruments

June 21st, 2019

Wooster, OH – Team geochemistry returned to Wooster this week with a serious focus on sample prep and data quality. Anyone with geochemical research experience understands the importance of preparing samples carefully and thoroughly, and having an analytical instrument that is well-calibrated for your samples. Some of our recent analyses have yielded surprising results, and now we’re double checking our sample prep process and instrument calibration to make sure the data are reliable.

Kendra and Layali are loading samples into the XRF. They are gaining a lot of hands-on experience operating the instrument.

The XRF measures the chemical composition of samples by exciting them with an X-ray beam. The X-ray beam causes the atoms in the sample to emit their own X-rays, which travel through a series of filters and crystals and are measured by a detector. The signal from the detector is converted to a concentration using a calibration curve that was made by measuring standards with known concentrations.

We are running the XRF at full capacity with drift-correct samples, unknowns, and standards, so that we can test the quality of the calibration and resulting data.

But we didn’t just work in the lab all week. We’re also preparing to for our upcoming trip to Iceland. We needed to pick up a few things, like rain gear. Only the essentials, of course.

Wooster undergraduate researchers expand their professional networks with cross-college collaboration

June 14th, 2019

Carlisle, PA – Our geochemistry research team spent this week at Dickinson College.

Hannah and Marisa analyzed the compositions of volcanic glasses and crystals using the scanning electron microscope (SEM-EDS).

They worked closely with Dr. Ben Edwards and Rob Dean (technician) to learn how to use the instrument. As with any new technique, it took a few days of practice to figure out how to obtain high quality data, but now we have hundreds of measurements to process when we return to Wooster.

Layali and Kendra processed major and trace element geochemical analyses of diabase from some Pennsylvanian rift basins.

They presented their work to Dr. LeeAnn Srogi and Dr. Tim Lutz, collaborators from West Chester University who visited us at Dickinson for a day. Layali and Kendra are contributing data to an oral presentation that Dr. Srogi will make at the 2019 IUGG General Assembly in July.

In the first two weeks of our undergraduate research project, our students have collaborated with scientists from three different institutions. They are building their professional networks and expanding their future opportunities.

In addition to all of the network-building and research productivity, we had a chance to sneak to nearby Hershey for a short visit (and some milkshakes).

The end of week 2 is bittersweet. Kendra, Layali, and Hannah head back to Wooster, parting ways with Marisa until we meet again in Iceland.

Thanks to everyone who made our Dickinson visit a success. We thank Dr. Ben Edwards and his family for their hospitality, Rob Dean for all of his assistance, Dr. LeeAnn Srogi and Dr. Tim Lutz for making the time to visit us and for excellent discussion, and the Dickinson Earth Science Department for their warm welcome.

Wooster and Dickinson students team up for geochemistry research

June 7th, 2019

[Wooster, OH] – A team of students from Wooster and Dickinson are working together on geochemistry research this summer. We’re using the compositions of Earth materials to understand geologic processes. Our main goal is to study the formation of volcanic ridges that were erupted beneath glaciers in Iceland, but we have a few other projects that we’ll be working on, too.  Thanks to Sherman Fairchild funding, we have 8 weeks to learn a lot of different lab techniques and travel to Iceland to get more samples.

We began our work with a weeklong marathon of preparing samples for analysis in the Wooster X-ray and Dickinson SEM labs.

Kendra and Layali prepared geochemical samples by melting powdered rocks and forming them into glass disks.

Marisa is examining samples of volcanic glasses under the microscope, selecting the freshest chips.

Kendra and Hannah are in the first stages of polishing the fresh glass chips so that they are perfectly smooth. This will let us analyze their compositions on Dickinson’s scanning electron microscope. We can also use the polished glass chips to measure the water contents later in the project.

Layali is tracing images of thin sections. We’ll use the tracings to do some quantitative mineralogical analyses.

It looks she is having fun doing all of this hard work!

The team has been working so hard that they have needed reminders to take breaks. So what to do on a break? How about a game of lab-bench-dino-mancala?

 

#GSA2017 Wrap Up

November 4th, 2017

It’s hard to believe that we were at the 2017 GSA Annual Meeting in Seattle, Washington just last week. Once again, the Wooster Geologists had a strong showing.

Macy Conrad (’18) kicked off our student presentations on Sunday with a poster on the paleoecology of encrusting sclerobionts in the Type Campanian of southwestern France. You can read more about Macy’s work in this Fossil of the Week blog post.

Brandon Bell (’18) followed Macy on Monday with his poster on the American scientific and cultural interaction with Japan and Europe after the 1906 earthquake. Brandon learned how historical methods can be used to study geologic phenomena like earthquakes and landslides.

You may remember Keck Geology Team Utah from their summer research exploits. They are Addison Thompson (’20, Pitzer), Madison Rosen (’19, Mt. Holyoke), Emily Randall (’20, Wooster), and Sam Patzkowsky (’20, Franklin and Marshall). At GSA, they presented the results of their research on dating young lava flows in the Black Rock Desert in Utah.

The intrepid Keck Geology Team Alaska, who also blogged about their summer research experiences, presented their dendrochronology research on declining yellow cedar and correlations with climate. They are Chris Messerich (’20, Washington and Lee), Malisse Lummus (’20, Trinity), Alora Cruz (’20, Macalester), and Josh Charlton (’19, Wooster).

Even our own Dr. Wilson had a poster presentation. His research on the bioerosion of oysters in the Type Campanian of southwestern France was the counterpart to Macy’s presentation.

As always, we had a fantastic alumni gathering where we caught up with recent graduates and former Wooster Geologists who have done wonderful things in their careers. Our students had an opportunity to interact with current graduate students, new geology department chairs, and emeritus faculty who specialize in paleontology, sedimentology, geochemistry, oceanography, and a vast range of Earth sciences. Once a Wooster Geologist, always a Wooster Geologist.

 

High-Temperature Geochemistry in Action

July 18th, 2017

WOOSTER, OH – Over the last couple of weeks, our Keck Geology Team Utah has been hard at work in the College of Wooster Geology labs. We collected a dozen samples from Ice Springs Volcanic Field in the Black Rock Desert, Utah to understand the eruption history and the age of the lava flows.

The first processing step is to powder the sample. Addison Thompson (’20, Pitzer College) uses the rock saw to isolate pieces of fresh rock.

Addison and Madison Rosen (’19, Mt. Holyoke College) use a sledge to break the sawn pieces into smaller bits.

Sam Patzkowsky (’20, Franklin and Marshall) cleans the chips so that we can crush them in the shatterbox.

Emily Randall (’20, College of Wooster) sieves the powder and makes sure all of it is small enough for the next step. We sent some of this powder to the Purdue PRIME Lab, where they’ll measure the abundance of 36Cl in our rocks.

Pa Nhia Moua (’20, Carleton College) pulls samples out of a red-hot oven so that we can measure Loss on Ignition (LOI) to determine how much H2O might be in the samples.

Sam and Addison weigh out accurate amounts of the oxidized sample and flux, which lowers the melting temperature and helps our samples melt so that we can make glass discs.

The samples get melted in the fluxer and poured into molds to make glass discs.

The glass discs are loaded in the XRF and analyzed for their major element chemistry. We use the chemistry along with the data from Purdue and the location and orientation of the sample to calculate an age for the lava flow.

We’re using another method called Varnish MicroLamination (VML) dating to provide an independent estimate of the age of the lava. Desert varnish is a dark coating of clays and iron- and manganese-oxides that accumulates on the surface of samples in arid environments. You may have seen ancient petroglyphs carved into the desert varnish. Researchers use the layering in VML to date pieces of rock art. In order to use the VML method, we have to make ultra-thin slides of our rocks so that we can see through the varnish.

Addison pours epoxy into plastic molds to mount the VML samples.

Pa Nhia has been sanding her VML sample for days to grind it to the correct thickness without grinding away the varnish. It’s dirty, delicate work.

By the end of the week, we should have age estimates for the lava flows and a better idea of the sequence of eruptive events that formed Ice Springs Volcanic Field. Check back later for our GSA abstract!

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