How we measure the chemical composition of Earth materials

May 25th, 2016

San Diego, CA – If you’ve been following our adventures, you know that we’ve started a project on Black Mountain with our collaborators at the University of San Diego. We’ve dedicated a significant portion of our time in California to sample preparation, and today we see the results of all of our hard work.

In order to address our research questions, we need to understand the compositions of the minerals, rocks, and soils that are present at the field site. To analyze mineral compositions, we are using a scanning electron microscope equipped with an energy-dispersive detector (SEM-EDS). The electron beam interacts with a polished rock specimen to produce characteristic X-rays. The detector separates those X-rays by energy, correlates the energy to specific elements, and maps the distribution of elements in the sample. This technique allows us to determine the compositions of individual minerals in our rocks.

Elizabeth Johnston (USD graduate student) and Dr. Beth O'Shea (USD) are examining mineral compositions using an SEM-EDS.

Elizabeth Johnston (USD graduate student) and Dr. Beth O’Shea (USD) are examining mineral compositions using an SEM-EDS.

Dr. Beth O'Shea (USD) and Amineh AlBashaireh ('18) examine soil samples and discuss analytical strategies.

Dr. O’Shea and Amineh AlBashaireh (’18) examine soil samples and discuss analytical strategies.

To analyze the bulk compositions of our soil samples, we’re using a benchtop X-ray fluorescence spectrometer (XRF). The XRF uses an X-ray beam to generate X-rays from the samples. The generated X-rays are characteristic of specific elements, which the XRF measures and compares to a calibration curve to calculate a concentration. This XRF model is equipped with several modes for analyzing soil or ore samples and allows us to analyze bulk compositions without destroying the sample.

Amineh is analyzing her soil samples with the benchtop XRF. She will use these data to guide her analytical work when we return to Wooster.

Amineh is analyzing her soil samples with the benchtop XRF. She will use these data to guide her analytical work when we return to Wooster.

Thinking like a scientist

May 24th, 2016

San Diego, CA – Thinking like a scientist is a challenging and important learning goal for the Wooster Geologists, and one of the primary reasons that we engage our students in undergraduate research. Although science is often portrayed as a collection of facts or as a series of exercises designed to prove something that is already known, our research students learn that science is a way of thinking. It is a method of inquiry that involves creativity, examining a question from multiple perspectives, and understanding uncertainty. Science requires hypotheses that are testable, data that can be collected and interpreted, and explanations that are supported by evidence. Today, our Black Mountain research group focused on these aspects of science as we developed our research goals and plans for the rest of the summer.

Amineh AlBashaireh ('18) filled the whiteboard with an impressive set of ideas and questions, which jump-started our research discussion.

Amineh AlBashaireh (’18) filled the whiteboard with an impressive set of ideas and questions to prompt our research discussion. On the left are “broad impacts” that define the significance of the research and put the research into context of the larger society. On the right are sources of “potential error,” which Amineh is recognizing and attempting to minimize.

Eventually, we developed a couple of research questions that Amineh will be able to address this summer. We formulated hypotheses for the answers to these questions and designed a research strategy that will generate the data necessary for testing our hypotheses. In the end, we created a research plan that is both achievable (given the constraints of time, expertise, resources, etc.) and flexible enough to allow the research to evolve as Amineh discovers new findings and develops new questions.

For an excellent resource on the process of science, check out the Visionlearning module by Anthony Carpi and Anne Egger. It’s an incredible resource for teachers and students alike.

References:

Carpi, A., and Egger, A.E. 2009. The process of science. Visionlearning POS-2 (8).

Geochemists know preparation is key

May 22nd, 2016

San Diego, CA – While the University of San Diego celebrated their commencement, we commenced lab work on the Black Mountain Project. We began by drying and sieving the soil samples that we collected earlier in the week.

Amineh AlBashaireh ('18) is removing her soil samples from the drying oven.

Amineh AlBashaireh (’18) is removing her soil samples from the drying oven.

Her soil samples display variety of colors and compositions.

Her soil samples display variety of colors and compositions.

Dr. Beth O'Shea (USD) and Amineh discuss the Munsell System for classifying the color of soil.

Dr. Beth O’Shea (USD) and Amineh discuss the Munsell System for classifying the color of soil.

While her samples dry, Amineh is helping prepare samples for analysis on the scanning electron microscope (SEM-EDS). Doesn't she look like a happy geochemist?While her samples dry, Amineh is helping prepare samples for analysis on the scanning electron microscope (SEM-EDS). Doesn’t she look like a happy geochemist?

Field Work on Black Mountain

May 21st, 2016

San Diego, CA – Amineh AlBashaireh (’18) and I are working with USD scientists, Dr. Bethany O’Shea, Elizabeth Johnston, and Eric Cathcart on the geology of Black Mountain in San Diego, CA.

Black Mountain Open Space Park is a popular hiking and mountain biking destination.

Black Mountain Open Space Park is a popular hiking and mountain biking destination.

The Santiago Peak Volcanics are exposed in the park. These rocks are early Cretaceous in age (~110 Ma) and are thought to represent the volcanic arc associated with the Peninsular Range batholith (Herzig and Kimbrough, 2014).

Slightly metamorphosed andesites and basaltic andesites are present as gray to dark gray aphanitic (fine grained) rocks with scattered phenocrysts (crystals) of plagioclase.

Slightly metamorphosed andesites and basaltic andesites are present as gray to dark gray aphanitic (fine grained) rocks with scattered phenocrysts (crystals) of white plagioclase.

There are also volcaniclastic rocks like this tuff breccia that include large clasts of andesites, basaltic andesites, and other fragmental rocks.

There are also volcaniclastic rocks like this tuff breccia that include large clasts of andesites, basaltic andesites, and fragmental volcanic rocks.

Outcrops of lapillistone contain accretionary lapilli, or rounded sphere of volcanic ash, that hint at the more turbulent and explosive nature of this volcano.

Outcrops of lapillistone contain accretionary lapilli, or rounded spheres of volcanic ash, that show evidence of the more turbulent and explosive nature of this volcano.

Hikers and bikers who visit Black Mountain may be less familiar with its volcanic history and more familiar with its mining history. In the 1920s, this area was briefly mined for arsenic. The arsenic was used in pesticides at the time.

Hikers and bikers who visit Black Mountain may be less familiar with its volcanic history and more familiar with its mining history. In the 1920s, this area was briefly mined for arsenic. The arsenic was used in pesticides at the time (Stewart, 1963).

Our research group is exploring one of the abandoned mines.

Our research group is exploring one of the abandoned mines.

In the mine waste, you can see shiny gold specs of aresenopyrite (FeAsS). Arsenopyrite is a sulfide mineral in which some of the sulfur is replaced with arsenic.

Amineh is studying trace element concentrations in the soils on Black Mountain. Here she is collecting samples. In the next few days, and over the course of the summer, we'll show you how she processes these samples in the lab.

Amineh is studying trace element concentrations in the soils on Black Mountain. Here she is collecting samples. In the next few days, and over the course of the summer, we’ll show you how she processes these samples in the lab.

This was a small (~30 cm) rattlesnake that we saw earlier in the day, and we take field safety seriously, so when we heard a rattle coming from the tall grass, we ended our sampling and called it a day.

This was a small (~30 cm) rattlesnake that we saw earlier in the day, and we take field safety seriously, so when we heard a rattle coming from the tall grass, we ended our sampling and called it a day.

It was an exciting, productive, and safe day in the field. More to come in the next few days as we start on our lab work.

References:

Herzig, C.T. and Kimbrough, D.L. 2014. Santiago Peak volcanics: Cretaceous arc volcanism of the western Peninsular Ranges batholith, southern California. GSA Memoirs 211: 345-363.

Stewart, R.M. 1963. Black Mountain Group in Weber, H.F., Geology and mineral resources of San Diego County, California: San Francisco, California Division of Mines and Geology, 49-50.

Wooster Geologists in San Diego, CA

May 20th, 2016

San Diego, CA – Wooster Geologists don’t waste any time getting to work on their summer research. Amineh AlBashaireh (’18) and I have made our way to the University of San Diego to start on a new research project with our collaborators in the Department of Environmental and Ocean Sciences. Our trip began with a tour of the department’s facilities in the impressive Shiley Center for Science and Technology.

The grand and welcoming entrance to the Shiley Center, which houses USD's science programs.

The grand and welcoming entrance to the Shiley Center, which houses USD’s science programs.

Visitors to the Department of Environmental and Ocean Sciences are greeted with this stunning display of a donated coral collection.

Visitors to the Department of Environmental and Ocean Sciences are greeted with this stunning display of a donated coral collection.

A favorite lunch spot is the Strata Plaza. The plaza was designed to represent the local stratigraphy and includes regional fossils, stones, and shells.

A favorite lunch spot is the Strata Plaza. The plaza was designed to represent the local stratigraphy and includes regional fossils, stones, and shells.

Our tour ended in the lab, where Dr. Bethany O'Shea and her graduate student, Elizabeth Johnston, gave us an overview of their work. Looks like they mean business!

Our tour ended in the lab, where Dr. Bethany O’Shea and her graduate student, Elizabeth Johnston, gave us an overview of their work. Looks like they mean business!

We’re looking forward to a full week of field and lab work. Stay tuned for more posts from sunny San Diego!

Good things happen at VMSG

January 7th, 2016

Dublin, Ireland – Congratulations to Mary Reinthal (’16) for a successful poster presentation at VMSG 2016!

image-5-768x1024_sizedMary did a fantastic job giving her ‘lightning talk,’ a two-minute round-robin-style presentation of her poster.

The poster session was everything that it should be. Mary received excellent feedback and advice on her research, met a number of people who are working on similar projects, and expanded her post-graduation career opportunities. She was an excellent representative of the Wooster Geology program. Well done!

Wooster Geologists in Ireland

January 6th, 2016

Greetings from Dublin! Mary Reinthal (’16) and I are attending the annual conference of the Volcano and Magmatic Studies Group (#VMSG2016) at Trinity College. Volcanologists, petrologists, geochemists, and geophysicists have gathered to share their research on igneous topics ranging from large igneous provinces (LIPs) to volcanic hazards. We started the conference, appropriately, with a tour of the architecture and building stones on Trinity’s campus.

The tour began in Parliament Square, so named for the Parliament that supported the construction of the surrounding buildings during the 1700s.

The tour began in Parliament Square, so named for the Parliament that supported the construction of the surrounding buildings during the 1700s.

In the background, you see the Chapel (1787-98), which is composed of the golden brown, granular Leinster granite. The windows are surrounded by Portland Stone, a fossiliferous limestone from Dorset.

The floor of the square is paved with polished glacial cobbles of a variety of lithologies, including limestone and andesite.

The floor of the square is paved with polished glacial cobbles of a variety of lithologies, including limestone and andesite.

Walkways of marble from China were added later to make the square more accessible.

Walkways of gneiss from China were added later to make the square more accessible.

Our last stop was the Museum Building, which houses the Geology and Engineering Departments. The building was recently cleaned in a painstaking effort that lasted ~4 years and involved the removal of gypsum deposits by dental drill and soot by a slow stream of water, but it was worth the effort. The architectural details of the Museum Building are breathtaking. On the exterior, the Portland Stone features intricate and unique carvings of leaves, birds, cats and mice, and other natural objects.

Visitors are greeted with robust pillars of limestone or Connemara marble.

Inside the building, visitors are greeted with robust pillars of limestone or Connemara marble.

Step past the pillars and you'll be awed by a soaring, colorful enameled brick ceiling.

Step past the pillars and you’ll be awed by a soaring, colorful enameled brick ceiling.

The Museum Building was the perfect venue for tonight’s conference ice-breaker, where we were finally able to connect faces to familiar names. Overall, it was a successful introduction to a vibrant and welcoming community of scientists. Tomorrow, Mary becomes an official member of that community when she’ll present her research on water on subglacial volcanics.

 

 

A True Liberal Arts Experience

December 9th, 2015

Guest Blogger: Mary Reinthal

If you were to poll the campus about their fall break, not many would say that they spent 20 hours over 2 days in an FTIR lab analyzing glass chips for volatile content. But if you were to ask geology senior Mary Reinthal and her advisor Dr. Meagen Pollock, that’s exactly what they would say. Fly in on a Monday; analyze samples at University of Massachusetts Amherst Tuesday and Wednesday; fly out Thursday. It was a lot of work, but somebody had to do it (for their Independent Study). The time was spent looking at the volatile spectra from individual, doubly polished glass chips collected from British Columbia, Canada.

Not a lot of windows in the FTIR lab, so Mary had to look at glass chips.

Not a lot of windows in the FTIR lab, so Mary had to look at glass chips.

After all that time in the lab, a lot of data were collected (yay!). These numbers will hopefully help us understand the evolution of glaciovolcanic tindars in British Columbia. Until then, however, these data will to be sifted through and looked at more closely as the semester continues.

Mary measuring thickness of glass wafers. To understand the bigger picture of volatile effects on eruptions you have to look small. Like micron-scale small.

Mary measuring thickness of glass wafers. To understand the bigger picture of volatile effects on eruptions you have to look small. Like micron-scale small.

Of course, the visit to U-Mass. Amherst wasn’t all science and glass chips. After finishing a 9-hour stint in the lab on Wednesday, Dr. Pollock and Mary ventured to Concord, Massachusetts to visit Walden Pond. In short, a truly liberal arts education was had by all.

Mary and Thoreau pondering life and science.

Mary and Thoreau pondering life and science.

 

ICP-MS OSU Adventure

September 14th, 2015

[Guest bloggers: Mary Reinthal and Chloe Wallace]

In five days, three Wooster geologists prepped and analyzed over 50 samples, ate tons of food, and learned a lot of science. Okay, maybe not tons of food, but we did eat a lot. For three solid days, rising junior Chloe Wallace and rising senior Mary Reinthal were able to dabble in wet chemistry at the Ohio State University under the guidance and supervision of Dr. Pollock. The days were spent in geochemistry labs preparing sieved whole rock samples for ICP-MS analyses.

For those not familiar, ICP-MS stands for Inductively Coupled Plasma-Mass Spectrometer. ICP-MS is a system that allowed us to determine trace elements in our samples, which better help us separate lithofacies units into distinctive geochemical groups. This, then, allows for a broader understanding of how and when these units were emplaced in relationship to one another. That’s a lot of information from some geochemistry.

Chloe and Mary in the clean lab.

Chloe and Mary in the clean lab.

One of the days, Chloe and Mary were able to get outside and venture around campus and check out some of the sights. But most days at OSU main campus were spent not in the sun, but in the basement, measuring solutions, precisely weighing powders, wearing clean-lab gear, or inputting data into the computer.

Chloe weighing whole-rock powders.

Chloe weighing whole-rock powders.

Mary pipetting acids into the vials to digest the samples.

Mary pipetting acids into the vials to digest the samples.

After long days of work, however, we got to peruse the campus scene, and we ate somewhere new every day. It was exhausting work, but the hope is for some good data.

Mary and Chloe celebrating the completion of sample preparation!

Mary and Chloe celebrating the completion of sample preparation!

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!

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