Category Archives: Geology

Krypton-ice : what the noble gases tell us about the ancient climate

Tree rings famously reflect the age of the tree, but they can also encode information about the environmental conditions throughout the organism’s life. A similar principle motivates the study of ice cores – traces of the ancient atmosphere are preserved in the massive ice caps covering Earth’s polar regions.

This Sunday’s guest is Olivia Williams, a graduate student here at Oregon State who is helping to uncover the wealth of climate information harbored by polar ice cores. Olivia is a member of the College of Earth, Ocean and Atmospheric Sciences (CEOAS), where she is advised by Christo Buizert. Their lab uses ice cores to study paleoclimatology and heads the Center for Oldest Ice Exploration (COLDEX), a multi-institution NSF collaboration.

Drilling an ice core in the Arctic or Antarctic is an expensive and labor-intensive process. As a result, once they have been studied by project leads, most American ice core samples are centrally managed by the National Ice Core Lab in Denver, CO and carefully allocated to labs throughout the country. Researchers analyze cross-sections of the larger ice core sample for many geochemical features, including dust records, stable isotopes, and evidence of volcanic eruptions. Determining the historical levels of carbon dioxide, methane, and other greenhouse gases is one application of ice core analysis that yields important insights into climate change.

Olivia’s project focuses on “melt layers”, which are formed by a large-scale melting and refreezing event. The frequency and intensity of melt layers help characterize polar summer temperatures, and specifically the number of days above freezing. Typically, researchers use visual examination or optical instruments to locate layers with relatively smooth and bubble-free ice. However, such methods can fail further down in ice cores, where clathrate ice formed by increased pressure excludes all bubbles. In response, the lab of Jeffrey Severinghaus at the Scripps Institution of Oceanography developed a chemical method to serve as a supplement. This technique extracts noble gases from the core and compares the ratio of the heavier (xenon and krypton) to argon, the lightest noble gas. Since the heavier noble gases are more water-soluble, spikes in the relative concentration of krypton and xenon suggest that a melting event occurred.

During a typical day in the lab, Williams takes samples from the ice core stored at -20 C in a large walk-in freezer and handles the samples in chilled ethanol baths. She particularly focuses on ice cores from Greenland and time periods such as the last interglacial period ~120 thousand years ago and the early Holocene ~12 thousand years ago. Since the OSU lab’s noble gas methodology is novel, Olivia’s work involves a lot of design and troubleshooting the extraction line, which extracts the trapped gases. One time, she even had to commission a scientific glassblower for custom cold traps in the extraction line.

Olivia presenting at the International Partnerships in Ice Core Science conference

Williams’ interest in geology was impressed upon her at an early age, in part by the influence of her grandfather, a longtime science writer for the Seattle Times. Her grandfather’s love for the geology of the Pacific Northwest inspired her to follow in his footsteps as a scientific journalist. At Boston University, Olivia initially planned to major in communications, until she took a seminar on interdisciplinary science communication offered by BU Antarctic Research Lab, together with education and earth sciences majors. This experience helped solidify her interest in geology, and she switcher her major to earth sciences. Her senior research project related to nutrient cycling in salt marshes, but she knew that she eventually wanted to work in polar science and paleoclimatology. Besides her research at OSU, Olivia has stayed active in science communication, serving as the outreach chair for the CEOS graduate student association. She has helped organize education tables at the Corvallis Farmer’s Market. In the future, Olivia hopes to pursue an academic career and continue research and teaching in the field she loves but is open to the full range of earth science career paths.

For more on Olivia’s exciting research and to hear what it is like to drill ice from a lava formation, tune in this Sunday, January 22nd at 7PM on KBVR 88.7 FM or look out for the podcast upload on Spotify!

What ice sheets can teach us about ancient ocean shorelines

Around 80,000 years ago, the Earth was in the middle of the late Pleistocene era, and much of Canada and the northern part of the United States was blanketed in ice. The massive Laurentide Ice Sheet covered millions of square miles, and in some places, up to 2 miles thick. Over vast timescales this ice sheet advanced its way across the continent slowly, gouging out what we now know as the Great Lakes, carving the valleys, depositing glacial tills, and transforming the surface geology of much of the southern part of Canada and northern US. Further west, the Cordilleran ice sheet stretched across what is now Alaska, British Columbia, and the northern parts of the Western US, compressing the ground under its massive weight. As these ice sheets depressed the land beneath them, the Earth’s crust bulged outwards, and as the planet warmed and the ice sheets began to melt, the pressure was released, returning the crust underneath to its previous shape. As this happened, ocean water flowed away, resulting in lower sea levels locally, but higher levels across the other side of the planet.

The effects of massive bodies of ice forming, moving, and melting are far from negligible in their impact on the overall geology of the region, the sea level throughout history, and the patterns of a changing climate. Though there are only two ice sheets on the planet today, deducing the ancient patterns and dynamics of ice sheets can help researchers fill the geological record and even make predictions about what the planet might look like in the future. Our guest on Inspiration Dissemination this week is PhD candidate and researcher Schmitty Thompson, of the Department of Geology in CEOAS. Thompson is ultimately trying to answer questions about ice distribution, sea levels, and other unknown parameters that the geologic record is missing during two different ice age warming periods. Their research is very interdisciplinary – Thompson has degrees in both math and geology, and also uses a lot of data science, computer science, and physics in their work. They are using computer modeling to figure out just what the shorelines looked like during this time period around 80,000 years ago.

*Schmitty Thompson, fourth year PhD candidate with Jessica Creveling in the Geology Department.*

“I use models because the geologic record is pretty incomplete – the further back you go, the less complete it is. So by matching my models to the existing data, we can then infer more information about what the shoreline was like,” they explain. To do this accurately, Thompson feeds the model what the ice sheets looked like over the course of around 250,000 years. They also need to incorporate other inputs to the model to get an accurate picture – variables such as the composition of the interior of the Earth, the physics of Earth’s interior, and even the ice sheets’ own gravitational pull (ice sheets are so massive they exert a gravitational pull on the water around them!)

Using math to learn about ice

The first equation to describe global changes in sea level was published in 1976, with refining throughout the 90s and early 2000s. Thompson’s model builds on these equations in two versions: one which can run in about 10 minutes on their laptop, and another which can take multiple weeks and must run on a supercomputer. The quicker version uses spherical harmonics as the basis function for the pseudospectral formulation, which is basically a complex function that does math and incorporates coefficient representations of the earth’s radius, meridional wave numbers, variation across north/south and east/west, and a few other variables. The short of it is that it can perform these calculations across a 250k time span relatively quickly, but it makes assumptions about the homogeneity of the earth’s crust and mantle viscosity. Think of it like a gumball: a giant, magma-filled gumball with a smooth outer surface and even layers. So while this method is fast, the assumptions that it makes means the output data is limited in its usefulness. When Thompson needs a more accurate picture, they turn to collaborators who are able to run the models on a supercomputer, and then they work with the model’s outputs.

While the model is useful for filling in gaps in the historical record, Thompson also points out that it has uses in predicting what the future will look like in the context of a changing climate. After testing out these models and seeing how sensitive they are, they could be used by researchers looking at much smaller time scales and more sensitive constraints for current and future predictions. “There are still lots of open questions – if we warm the planet by a few degrees, are we going to collapse a big part of Antarctica or a small part? How much ice will melt?”

To learn more about ice sheets, sea levels, and using computer models to figure out how the shoreline looked thousands of years ago, tune in to Schmitty Thompson’s episode on Inspiration Dissemination this upcoming Sunday evening at 7 PM PST. Catch the show live by streaming on https://kbvrfm.orangemedianetwork.com/, or check out the show later wherever you get your podcasts!

Thompson was also recently featured on Alie Ward’s popular podcast Ologies. You can catch up with all things geology by checking out their episode here.

Libraries of possibilities: Algorithmic identification of possible fossil chronologies

Cedric Hagen, a doctoral candidate in the College of Earth, Ocean, and Atmospheric Sciences, spends a lot of time thinking about fossils. He’s not a paleontologist, though: don’t expect to find him digging up a Tyrannosaurus Rex. For one thing, dinosaurs lived much too recently–a measly 66 million years ago, in the case of the T. rex. Cedric’s work takes him much, much further back in time to the beginning of the Cambrian era, which began over 500 million years ago.

PhD candidate Cedric Hagen (photo by Hannah O’Leary)

While the Cambrian era is not the beginning of life on earth (for that, you’d need to go back a staggering 3.5 billion years) the Cambrian era is important because that is the time when many of the major forms of life appeared. This includes, for example, spongelike animals, burrowing worms, creatures with carbonate shells, reef-forming animals, and arthropods like the remarkably successful trilobites. The apparent rapid increase in the diversity of life at this time is termed the Cambrian explosion.

*Trilobite. Public domain image from Wikimedia Commons, accessed 5/17/2020. Ellipsocephalus Hoffi detail (Cambrian Trilobite) (Fig. 31) (b), from “The ancient life-history of the earth” (Page 85)*

As you may imagine, there are numerous challenges to studying life from so long ago. One of the major challenges is that there simply aren’t very many samples in existence. Part of the problem is that although the rocks at the ocean floor are old from a human standpoint, since oceanic crust is continually formed at mid-ocean ridges and destroyed at deep-sea trenches, there’s a hard limit on the age of fossils you can find at the sea floor. Oceanic crust is at most about 200 million years old throughout most of the world’s oceans. While there are a few places in the Mediterranean that date back around 340 million years, even that is a couple hundred million years too young. Only at isolated locations on the continents are there places where Cambrian carbonate rock formations exist. “You can think of these as reefs, really old reefs,” Hagen said.

Carbonate rocks outcropping in the southern Nopah Range, Death Valley, CA (photo by Cedric Hagen)

Before the advent of carbon isotope and radiometric dating, geologists had to base their ordering of the fossil record on relative positioning in layers of rock and fossil co-occurrence. Sedimentary rock forms as layers of material (strata) pile up over time. So, the more strata above a fossil, the further back in time the fossil formed. If you find multiple fossils in one area, this is a reliable way to place the fossils in chronological order—that is, of course, if those layers haven’t been jumbled up by earthquakes, landslides, or tectonic folding in the meantime. An additional help is that the events that lead to fossilization, such as a mudslide, frequently result in many organisms being fossilized together. If the same species is found at two sites, it is likely that the two sites represent the same era. This lets scientists pin approximate dates on the co-occurring fossils.

Radiometric dating allows precise measurement of age based on the decay of radioactive material. As radioactive material decays, atoms of one element are transformed into another. For example, uranium decays (through a convoluted process) into lead. Measuring the relative abundance of each element allows one to calculate the age of the sample. Since these rocks are made in part from the remnants of carbon-shelled organisms, they also record the amount of particular isotopes of carbon that were present at the time that the organism died. Since the relative abundance of carbon isotopes varies slowly through time, the pattern of carbon isotope concentrations in a sample of carbonate rock is like a record of the rock’s position in time.

“We’ve pulled together these records that have different chunks of time, and we’re trying to correlate them to a single high resolution record that we know the time of so we can know the order of the fossils, ” Hagen says. “What we’ve started to find is that the uncertainty in these measurements is quite large, larger than previously anticipated—there’s a lot of different places and times where things could have evolved.”

Prior to this research, scientists lined up carbon isotope chronologies visually. Hagen has been working on numerical algorithm that allows a computer to identify possible matches between rock samples from different parts of the world. “We’re cataloging libraries of possibilities,” says Hagen. “Are there twenty [possible arrangements]? Are there two? What could we do as geologists to go into the field and pick one or two of those and narrow down this uncertainty?”

To hear more about Cedric’s research, tune in on Sunday,May 15^th at 7 PM on KBVR 88.7 FM. You can live stream the show, or, if you miss it, you can download this episode and most of our earlier shows as podcasts on iTunes.

Heavy Digging

Mine Algae!!!

When I think of mining, the first thing that comes to mind is the classic gold rush miners from the mid-1800s. Someone that looks a lot like Stinky Pete from Toy Story 2. I don’t mean to imply that this is, or isn’t, what a miner looks like. However, this does say something about the general lack of thought about mining practices. The EPA certainly isn’t as ignorant about mines as I am; in fact, as of 2014, they had designated over 1,300 sites around the country as superfund sites requiring extensive cleanup efforts. Tullia Upton is also thinking about mines much more deeply than the average person, and she is uncovering some alarming information.

During a road trip through southern Oregon, Tullia was bummed when she was told it was unsafe to swim in a local river, so she decided to dive a bit deeper, figuratively of course. She learned that this area has become dangerously polluted due to waste products of the Formosa mine.

The Formosa mine near Riddle, OR

Mining practices involve extensive digging and extracting of heavy metals which are normally buried in a reducing environment deep down within the earth’s sediment. The process of digging up these heavy metals leaves behind a staggering amount of unused material, known as tailings. Mining also exposes the metals to oxygen and allows them to leach into soils and the watershed. Due to runoff from the tailings and other waste at the Formosa mine, there is now an estimated 18 mile dead zone where no organism can live. The full extent of the damage being done to the local watershed has not been thoroughly mapped though.

Tullia analyzing samples in the lab

As she learned more about the dangerous metals coming from the mine, Tullia immediately got involved as a volunteer and secured research funding to study the pollution occurring at the Formosa mine. Tullia hopes to map the full extent of runoff from the Formosa mine and provide a better picture of the mess for the EPA, and other scientists, working on the cleanup process. When she finishes her Ph.D. here in Environmental Sciences, Tullia hopes to move on to a post-doc and eventually run her own research lab.

Tune in this Sunday, October 9th at 7pm PST to hear more about mine pollution and Tullia’s unique journey to grad school at OSU.

Hungry, Hungry Microbes!

Today ocean acidification is one of the most significant threats to marine biodiversity in recorded human history. Caused primarily by excess carbon dioxide in the atmosphere, the decreasing pH of the world’s oceans is projected to reach a level at which a majority of coral reefs will die off by 2050. This would have global impacts on marine life; when it comes to maintaining total worldwide biodiversity, coral reefs are the most diverse and valuable ecosystems on the planet.

Unfortunately, there is reason to believe that ocean acidification might proceed at levels even faster than those predicted. Large resevoirs methane hydrates locked away in deep sea ice deposits under the ocean floor appear to be melting and releasing methane into the ocean and surrounding sediments due to the increasing temperature of the world’s oceans. If this process accelerates as waters continue to warm, then the gas escaping into the ocean and air might accelerate ocean acidification and other aspects of global climate change. That is, unless something– or someone– can stop it.

The area of the seafloor Scott studies lies several hundred to a few thousand meters below the surface–much too deep (and cold!) to dive down. Scott gets on a ship and works with a team of experienced technicians who use a crane to lift a device called a gravity corer off the ship deck and into the water, lowering it until it reaches the bottom, capturing and retrieving sediment.

This is where methanotrophs and Scott Klasek come in. A 3rd year PhD student in Microbiology at Oregon State University, Scott works with his advisor in CEOAS Rick Colwell and with Marta Torres to study the single celled creatures that live in the deep sea floor and consume excess methane. Because of their importance in the carbon cycle, and their potential value in mitigating the negative effects of deep sea methane hydrate melting, these methanotrophs have become a valuable subject of study in the fight to manage the changes in our environment occurring that have been associated with anthropogenic climate change.

Here Scott is opening a pressure reactor to sample the sediment inside. Sediment cores retrieved form the ocean floor can be used for microbial DNA extraction and other geochemical measurements. Scott places sediment samples in these reactors and incubates them at the pressure and temperature they were collected at, adding different amounts of methane to them to see how the microbial communities and methane consumption change over weeks and months.

Most people don’t wake up one morning as a kid and say to themselves, “You know what I want to be when I grow up? Someone who studies methanotrophs and the threat of warming arctic waters.” Scott Klasek is no exception, in fact, he went into his undergraduate career at University of Wisconsin, Madison expecting to pursue an academic career path in pre med. To learn all about Scott’s research, and the twists and turns that led him to it, tune in this Sunday, April 10th, at 7pm to 88.7 KBVR FM or stream the show live!

The Winds of Mars

False-color image of channel-confined TARs in the Amenthes Rupes Region, Mars (NASA/JPL/University of Arizona)

On our own world, dust storms can carry sands from the Sahara around the globe.On Mars, immense dust storms worthy of a Mad Max reference and formations called Transverse Aeolian Ridges up to a meter tall are common sights. Unlike Earth, where we constantly see geoactive forces like water, ice, and volcanic activity changing the landscape around us, the only force we can see actively changing the landscape of Mars is the wind. With desertification increasing on our own planet dune fields in many locations are moving into existing agricultural areas. Might we eventually be living on a world where the impact of wind on the land is as great as it is on Mars? Can the windswept world of Mars tell us what life will be like someday here on Earth?

Gravel ripple wind-formed bedforms in Puna de Atacama, Argentina (de Silva et al., 2013)

Rover image of Transverse Aeolian Ridges (TARs) in Endurance Crater, Mars (NASA/JPL/University of Arizona)

Michelle Neely, a master’s student in Geology and Geophysics studying under Shan de Silva, is investigating just that. By studying wind shaped formations called symetrical bed forms in the high desert of Argentina, which are the Earth’s closest analog to the ridges formed by the winds of Mars, Michelle hopes to learn how wind processes work on both worlds. If terrestrial desertification leaves our Blue Planet looking a lot more like the Red Planet, this research will prove invaluable.

For more on the geological history of Mars and our own future, tune in to 88.7 FM Sunday November 8th at 7pm PST or stream live to find out!

From Records in the Reef to Stories in the Snow: One Student’s Journey from Florida to Antarctica to Study the Geological History of the Earth

Tonight at 7 pm Pacific time Nilo Bill joins the hosts of Inspiration Dissemination to discuss his research in the Geology Program of the College of Earth Ocean and Atmospheric Sciences. Tune in to 88.7 FM KBVR Corvallis, or stream the show live, here!

Working underneath Peter U. Clark, Nilo studies paleoclimate, the ancient climate of the Earth. By examining erratic boulders in the West Antarctic Ice Sheet moved by glacial decay between 10 and 20 thousand years ago Nilo tries to understand when and why the Antarctic ice sheets began to recede. For example: How much of this change can be attributed to CO2 increases in the atmosphere? When the sea levels rose after the last ice age, what glaciers did most of the water come from?

The West Antarctic Ice Sheet. Image from: http://learningfromdogs.com/tag/west-antarctic-ice-sheet/

Nilo became interested in the question of ancient climate and sea level rise far from Oregon State or any ice sheets, in the geomicrobiology lab at University of Miami, where he studied coral reefs to learn how much water levels rose 10 to 20 thousand years ago during the last large scale glacial melt.

Nilo’s work on ancient climate allows us not only to better understand the history of the world, but also where we are headed, as we continue to contribute to increasing atmospheric CO2 levels. Increases in atmospheric CO2 that have been linked to global climate changes and glacial melt in the past are being seen again in our own time, but at much faster rates. Whereas in the past these changes occurred over a span of nine to ten thousand years, humans have artificially increased global CO2 by comparative levels in only one hundred years.

By understanding how the earth has behaved under similar circumstances in the past, Nilo hopes that we might better predict what will occur in our own future.