Lab Character(s)

May 25th, 2017

Chapel Hill, NC – Every scientist who works in a lab knows that labs have unique characters. The Isotope Geochemistry lab at UNC Chapel Hill was bustling with Ph.D. researchers, graduate students, undergraduate students, and researchers from other institutions, including Appalachian State University and The College of Wooster. We could tell it was a happy lab community by all of the happy faces. The faces weren’t just on the researchers; they were drawn on windows, hoods, and sticky notes.  Here are few to brighten your day.

There was a single angry face in the bunch. We called this Samarium Face (Sm-face) because Sm is apparently a finicky element to analyze by mass spectrometry. Maybe someone should make a Sm-face emoji.

Isotope analysis by TIMS is FUN

May 23rd, 2017

Chapel Hill, NC – Wooster Geologists have been hard at work preparing samples for isotope analysis. Now that sample preparation is complete, the next step is to analyze them on the thermal ionization mass spectrometer (TIMS). In the TIMS, a sample heats up until it ionizes, created a beam of charged particles.

The charged particles are sent through a mass spectrometer, which accelerates the ions through a curved path in a magnetic field. The ions separate based on their mass to charge ratio. The separated beams of ions are sent to collectors that convert the ions into an electrical signal that can be used to determine the sample’s isotopic composition. Figure from Revesz et al. (2001).

For a complete overview of how the TIMS works, check out this website at SERC.

 

Our tiny samples get loaded onto tiny filaments that heat up in the instrument. The filaments are stored in neat, orderly rows in a cabinet in the TIMS lab. If you look closely, you’ll see the flat ribbon onto which we’ll mount our samples.

You can imagine that the filament loading process is as meticulous as the sample preparation work. Here, Ben Kumpf (’18) pipettes a sample onto the filament.

This is what our sample looks like before we heat up the filament. It’s a single drop.

The filaments will get loaded into the TIMS instrument. This is one of the TIMS instruments here at the University of North Carolina Chapel Hill that we’ll use to analyze for strontium (Sr).

This is the exciting part, when we hope that all of our hard work as paid off. It’s a lot of effort for a single data point, but we know it’s well worth it.

References

Revesz, K.M., Landwehr, J.M., and Keybl, J. 2001. Measurement of bigsymbol13C and bigsymbol18O Isotopic Ratios Of CaCO3 using a Thermoquest Finnigan GasBench II Delta Plus XL Continuous Flow Isotope Ratio Mass Spectrometer with Application to Devils Hole Core DH-11 Calcite: USGS Open-File Report 01-257. US Government Printing Office.

Extracting a single element from a rock

May 20th, 2017

Chapel Hill, NC – As you know, Ben Kumpf (’18) and I are working in the Isotope Geochemistry lab at UNC Chapel Hill. We are measuring isotopes of strontium (Sr), lead (Pb) and neodymium (Nd) in basaltic pillow lavas from northern British Columbia. In order to measure the elements, we need to isolate them from the rest of the elements that make up our rocks. We purify individual elements using the method of column chemistry. A column is like a filter for elements; we pass our sample through the column and the column captures the element of interest, then we release and collect the element off the column to be analyzed later.

The first step to preparing our samples is to dissolve our rock powders in an acid solution. Ben Kumpf (’18) weighs small amounts of rock powder into Teflon vials. We add a series of acids to the vials and let them sit on a hotplate for a day or two until the powders are completely dissolved.

Once the samples are dissolved, we measure out a small amount of the solution into a new vial to run it through the column chemistry process. The first step to make a column “load” solution is to dry the sample solution down to a powder on a hotplate.

To the dried-down powder, we add an acid that is appropriate for the column that we’re using. For Sr, we’re adding nitric acid to the vials.

Now we’re ready to set up the columns. Dr. Ryan Mills (psychedelic lab coat) is showing Ben Kumpf (’18) how to add the resin.

This is what a column looks like up close. It’s suspended above a waste beaker. The white material that is filling the tube and neck is the resin. You can see it still settling out of solution. The resin that we use to isolate Sr was developed in response to the Chernobyl accident when it became necessary to remove radioactive Sr from milk (Vajda and Kim, 2010).

The chemical column process involves adding a series of solutions to the columns in a sequence that cleans the resin, conditions the resin for the sample load solution, introduces the sample, and rinses the sample through the resin. There’s a lot of pipetting and waiting for the solutions to move through the column during this stage.

Samples are centrifuged prior to loading. The centrifuge separates any undissolved solids from the liquid so that we only add the liquid portion to the column.

These columns are loaded with our Pb solutions.

Now that our sample has passed through the column, we release all of the Sr or Pb off of the column and collect it in our sample vial.

The last step in the process is to dry down the sample one final time. This makes a tiny bead at the bottom our vial. We will load this bead into a mass spectrometer to measure the isotope composition.

Now you can see why we need do our sample preparation in a clean lab.

References

Vajda, N. and Kim, C.-K. 2010. Determination of radiostrontium isotopes: A review of analytical methodology. Applied Radiation and Isotopes 68: 2306-2326.

What is a clean lab?

May 16th, 2017

Chapel Hill, NC – Ben Kumpf (’18) and I are at the University of North Carolina at Chapel Hill to use their lab facilities for isotope analysis. We’re working with small amounts of sample and the instrument has a high degree of analytical precision and sensitivity, so all of our sample preparation occurs in the class-1000 clean lab. A clean lab is a room that is specifically designed to limit the amount of airborne contaminants. Special air filters and air distribution systems keep the environment clean so that we can minimize contamination while we separate and purify the isotopes.

Clean labs are classified based on the amounts of specifically sized particles allowed in a cubic meter (~35 cubic feet) of air. If we sample a cubic meter of air in the class-1000 lab and measure the amount of particles that are 5 microns in diameter, we would count no more than 293! For comparison, human hair has a diameter of about 50 to 100 microns, so we’re talking about really tiny bits of airborne dust. Class-1000 refers to Federal Standard 209E, where class-1 is the cleanest space and class-100,000 is the dirtiest (but still pretty darn clean). Federal Standard 209E has been replaced by International Organization for Standardization ISO 14644-1 standards. The new standards include one dirtier and two cleaner classifications and are numbered ISO-1 to ISO-9. Class-1000 is equivalent to ISO-6. UNC Chapel Hill also has a class-100 (ISO-5) clean lab where they process zircons for U-Pb dating.

Before we enter the clean lab, we gear up in the gowning room. The garments are designed to protect the wearer and minimize contamination from the wearer’s body. We wear standard lab safety attire, like glasses, gloves, and a lab coat. We also remove our shoes and exchange them for designated (comfy) slip-on shoes that only go in the clean lab.

Ben Kumpf (’18) models the clean lab outfit, complete with matching Carolina Blue accents. I see a theme.

Let the summer research commence!

May 15th, 2017

Chapel Hill, NC – As the College of Wooster Commencement ceremony was just finishing, our rising seniors were starting their summer research. Ben Kumpf (’18) and I are visiting the labs in the Department of Geological Sciences at the University of North Carolina at Chapel Hill. We are using their Isotope Geochemistry Lab to measure Sr-Nd-Pb isotopes of pillow lavas from our study site in northern British Columbia. The first step in the process is to dissolve our rock powders using several strong acids. Fortunately, we were able to send some of our samples in advance, and the good folks here at UNC dissolved about half of our samples for us.

Ben Kumpf (’18) went straight from his flight to the lab and is already hard at work. He measured portions of the dissolved samples into new vials so that we can prepare them for Sr isotope analysis. The dissolved samples will be made into solutions that we’ll use tomorrow.

Look for our posts in the following week to learn more about how isotopes are analyzed and what we hope to learn.

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!

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!

The Bear Post

July 25th, 2014

One of the wonderful benefits of working in the wilderness is the potential for interaction with wildlife. Sometimes, we’re entertained by energetic jackrabbits. Sometimes, camels eat our lunch. Always, we keep safety at the forefront.

The British Columbia team was fortunate to see majestic bald eagles, curious stone sheep, and many (many) marmots in their natural habitat. We also saw several bears.

Most of the bears that we saw were black bears eating the fresh grass alongside the road.

Most of the bears that we saw were black bears eating the fresh grass alongside the road.

However, the very first night in the field, we saw grizzlies.

The yellow arrow is pointing to a momma grizzly and her cub. Part of our group is standing on the edge of our campsite.

The yellow arrow is pointing to a momma grizzly and her cub. Our anxious group is standing on the edge of our campsite.

We were well prepared for a moment like this. Before going to the field, we had several long discussions about bear safety. We knew that the best strategy is to avoid a confrontation. At all times, each of us carried our own bear spray, a pepper spray with a strong propellant. We also had bear bangers, fire-cracker cartridges that are launched with a pen-like launcher. One of the first things we did when we arrived in the field was practice using the bear spray and bear bangers.

The bangers worked just as they were designed when we used them that first night. We spotted the momma grizzly and her cub walking across the ridge toward our camp. They didn’t change their course after the first bear banger, so we set off another. The second banger caused them to stop, and the third startled them into running in the opposite direction. Confrontation avoided!

As an added precaution, we set up a portable electric bear fence around our tents. The gentle tick of the fence was a comfort at night.

Another Perspective on British Columbia

July 17th, 2014

Guest blogger: Liz Plascencia

15 days. 22 bears. 4 bald eagles. 47 rock samples.

Wow. What a trip. I, a native Los Angeles city dwelling kid, have had the utmost pleasure of accompanying such a dynamic and energetic team of geologists to Mt. Edziza. Northern British Columbia is absolutely unreal. Far from the city lights and piercing sirens, our camp was nestled between Pillow Ridge and Tsekone Ridge. We spent a solid five days in the field collecting a variety of physical samples such as pillow lava, breccia, lapilli tuff, xenoliths, etc. We also spent a great deal of time quantitatively and qualitatively describing pillow lava from the west side of Pillow Ridge with trend and plunge measurements, vesicularity estimates, phenocrysts estimates, and horizontal and vertical measurements. Within those five days we celebrated a birthday (HAPPY BIRTHDAY MEAGEN), Canada Day, The Fourth of July, and overall triumph of a great trip.

The team observing a dyke at Second Canyon, Wells Gray Provincial Park, BC.

The team observing a dyke at Second Canyon, Wells Gray Provincial Park, BC.

Eve Cone in the distance at dusk.

Eve Cone in the distance at dusk.

Quite possibly the greatest thrill of my life, so far.

Quite possibly the greatest thrill of my life, so far.

We are back in lab for these next couple of weeks processing the rock samples from the field. I am really going to miss these two goons. Mary and Julia were the most welcoming Scots. Hopefully there will be more Dickinson College and The College of Wooster collaborations in the near future.

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