Earth Sciences

Global

Recent satellite data reveal that the Konya Basin in the Central Anatolian Plateau of Türkiye is continually being reshaped over millions of years, according to a new analysis led by Earth scientists at the 91�Թ�.

The researchers say experimental simulations – combined with geological, geophysical and geodetic data – explain the enigmatic sinking of the basin within the rising plateau interior and further suggests a new class of plate tectonics that has implications for other planets that do not have Earth-like plates such as Mars and Venus.

The study, published in Nature Communications, shows the sinking in the region is due to multi-stage lithospheric dripping – a phenomenon named for the instability of rocky material that makes up Earth’s crust and upper mantle. As dense rock fragments beneath the surface detach and sink into the more fluid layer of the planet’s mantle, major landforms such as basins and mountainous folding of the crust form at the surface.

“Looking at the satellite data, we observed a circular feature at the Konya Basin where the crust is subsiding or the basin is deepening,” says lead author Julia Andersen, a PhD candidate in 91�Թ�’s department of Earth sciences in the Faculty of Arts & Science.

“This prompted us to look at other geophysical data beneath the surface where we saw a seismic anomaly in the upper mantle and a thickened crust, telling us there is high-density material there and indicating a likely mantle lithospheric drip.”

Artist’s impression of the multi-stage lithospheric dripping process in Central Anatolia (illustration by Nevena Niagolova)

The results echo a similar investigation by the researchers into the formation of the Arizaro Basin in the Andes Mountains of South America, suggesting the phenomenon can occur anywhere on the planet and explains tectonic processes typically found within mountain plateau regions.

Past studies show the Central Anatolian Plateau has risen by as much as one kilometre over the past 10 million years because of the lithospheric dripping phenomenon.

“As the lithosphere thickened and dripped below the region, it formed a basin at the surface that later sprang up when the weight below broke off and sank into the deeper depths of the mantle,” says Russell Pysklywec, a professor in the department of Earth sciences and a co-author of the study.

“We now see the process is not a one-time tectonic event and that the initial drip seems to have spawned subsequent daughter events elsewhere in the region, resulting in the curious rapid subsidence of the Konya Basin within the continuously rising plateau of Türkiye.”

Andersen adds that the new findings suggest a connection between plateau uplift and basin formation events through the evolution of primary and secondary lithospheric removal. “Essentially, subsidence is occurring alongside the ongoing uplifting of the plateau.”

Andersen and study co-authors, including colleagues at Istanbul Technical University and Çanakkale Onsekiz Mart University in Türkiye, arrived at their findings after recreating the dripping process in laboratory experiments and analyzing their observations.

They built laboratory analogue models to establish how the process may have unfolded based on the data provided by the new measurements, filling a plexiglass tank with polydimethylsiloxane (PDMS) – a silicone polymer fluid approximately 1,000 times thicker than table syrup – to serve as Earth’s fluid lower mantle, adding a mixture of PDMS and modelling clay to replicate the upper-most solid section of the mantle, finishing with a sand-like layer on top made from ceramic and silica spheres to serve as Earth’s crust.

Artist’s impression of two types of lithospheric drip: one produces thickening and uplift of Earth’s crust, while the other results in the formation of a basin at the surface without horizontal deformation (illustration by Julia Andersen/91�Թ�)

The researchers activated the model by inserting a high-density seed into the PDMS and modelling clay layer to initiate a drip that was subsequently pulled downward by gravity. A set of cameras were positioned above and beside the tank to record any changes over time, capturing a high-resolution image roughly every minute.

“Within 10 hours, we observed an initial phase of dripping, which we call a primary drip. After that primary drip touched the bottom of the box, we saw a second drip had begun to sink to the bottom after 50 hours,” says Andersen. “Both the primary and secondary drip were not causing any horizontal deformation in our artificial crust, which we expect is typically associated with a mantle lithospheric drip.”

The researchers already knew that the primary drip had caused changes in surface topography of the experiment, and wanted to know if the secondary drip would have any effect on the surface since it was a smaller sized drip than the primary drip. “What we noticed was that over time, this secondary drip did pull the crust downward and started to create a basin, despite no horizontal movements in the crust at the surface,” Andersen says. “The findings show these major tectonic events are linked, with one lithospheric drip potentially triggering a host of further activity deep in the planetary interior.”

91�Թ� geoscientists shed new light on plate tectonics

Christopher.Sorensen — Tue, 06 Feb 2024 17:08:10 +0000

91�Թ� geoscientists shed new light on plate tectonics

Christopher.Sorensen Tue, 02/06/2024 - 12:08

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Researchers have discovered undersea faults on the Pacific plate, some of which are hundreds of kilometres long (image by NOAA/NASA GOES Project)

Chris Sasaki

Topic

91�Թ� Scarborough

Subheadline

The researchers found that the Pacific plate is scored by large undersea faults that are pulling it apart

A team of geoscientists from the 91�Թ� is shedding new light on the century-old model of plate tectonics, which suggests the plates covering the ocean floors are rigid as they move across the Earth’s mantle.

The researchers found that the Pacific plate is scored by large undersea faults that are pulling it apart. The newly discovered faults, described in a paper published in the journal Geophysical Research Letters, are the result of enormous forces within the plate tugging it westward.

Some of the faults are thousands of metres deep and hundreds of kilometres long.

Erkan Gün (photo by Don Campbell)

“We knew that geological deformations like faults happen on the continental plate interiors far from plate boundaries,” says Erkan Gün, a post-doctoral researcher in the department of physical and environmental sciences at 91�Թ� Scarborough. “But we didn't know the same thing was happening to ocean plates.”

Russell Pysklywec, a professor in the department of Earth Sciences in the Faculty of Arts & Sciences, adds that the research contributes to a fuller understanding of the field.

“What we're doing is refining plate tectonics – the theory that describes how our planet works – and showing those plates really aren't as pristine as we previously thought.”

Other researchers involved in the study include Phil Heron, an assistant professor in the department of physical and environmental sciences at 91�Թ� Scarborough, as well as researchers from the Eurasia Institute of Earth Sciences at Istanbul Technical University.

For millions of years, the Pacific plate – which constitutes most of the Pacific Ocean floor – has drifted westward to plunge down into the Earth’s mantle along undersea trenches or subduction zones that run from Japan to New Zealand and Australia. As the western edge of the plate is pulled down into the mantle, it drags the rest of the plate with it like a tablecloth being pulled from a table.

The newly discovered plate damage at the faults occurs within extensive, sub-oceanic plateaus formed millions of years ago when molten rock from the Earth’s mantle extruded onto the ocean floor; the faults tend to run parallel to the closest trench.

“It was thought that because the sub-oceanic plateaus are thicker, they should be stronger,” says Gün. “But our models and seismic data show it’s actually the opposite: the plateaus are weaker.”

In other words, if the Pacific plate is like a tablecloth being pulled across a tabletop, the plateaus are patches of weaker cloth that are more prone to tearing.

Russell Pysklywec on the south slope of Mount Tongariro in New Zealand (supplied image)

The researchers studied four plateaus in the western Pacific Ocean – the Ontong Java, Shatsky, Hess and Manihiki – in a vast area roughly bounded by Hawaii, Japan, New Zealand and Australia. They made their discovery using supercomputer models and existing data – some collected in studies done in the 1970s and ‘80s.

“There is evidence that volcanism occurred at these sites in the past as a result of this type of plate damage – perhaps episodically or continuously – but it isn’t clear if that’s happening now,” says Gün. “Still, we can’t be certain because the plateaus are thousands of metres below the ocean surface and sending research vessels to collect data is a major effort. So, in fact, we’re hopeful our paper brings some attention to the plateaus and more data will be collected.”

The theory of plate tectonics has been refined over many decades by numerous Earth scientists, including 91�Թ�’s John Tuzo Wilson, who made significant contributions to it during his career.

“But the theory’s not carved in stone and we’re still finding new things,” says Pysklywec. “Now we know this fault damage is tearing apart the centre of an ocean plate – and this could be linked to seismic activity and volcanism.

“A new finding like this overturns what we’ve understood and taught about the active Earth,” he says. “And it shows that there are still radical mysteries about even the grand operation of our evolving planet.”

High levels of 'forever chemicals' found in paper takeout containers: Study

Christopher.Sorensen — Tue, 28 Mar 2023 18:42:54 +0000

High levels of 'forever chemicals' found in paper takeout containers: Study

Christopher.Sorensen Tue, 03/28/2023 - 14:42

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(photo by Jann Huizenga/iStock/Getty Images)

Topic

Institutional Strategic Initiatives

Sustainability

From makeup to clothing and furniture, so-called “forever chemicals” are everywhere – including the paper bowls and containers used to package Canadian fast-food meals.

In a recent study published in Environmental Science and Technology Letters, Miriam L. Diamond, a professor in the 91�Թ�’s department of Earth sciences and School of the Environment in the Faculty of Arts & Science, and her team examined 42 paper-based wrappers and bowls – often billed as an environmentally friendly alternative to single-use plastics – collected from fast-food restaurants in Toronto.

They were looking for potentially toxic human-made perfluoroalkyl and polyfluoroalkyl substances (PFAS), of which there are more than 9,000 in the world.

The most abundant compound detected in the samples was 6:2 FTOH, or 6:2 fluorotelomer alcohol – a PFAS that is known to be toxic. Another finding: fibre-based moulded bowls that are marketed as “compostable” had PFAS levels three to 10 times higher than paper doughnut and pastry bags.

Miriam Diamond

“As Canada restricts single-use plastics in food-service ware, our research shows that what we like to think of as the better alternatives are not so safe and green after all,” Diamond says. “In fact, they may harm our health and the environment by providing a direct route to PFAS exposure – first by contaminating the food we eat, and after they’re thrown away, polluting our air and drinking water.

“The use of PFAS in food packaging is a regrettable substitution of trading one harmful option – single-use plastics – for another.”

The research team included Hui Peng, an assistant professor in the department of chemistry, and, from the department of Earth sciences, recent graduates Anna Shalin and Diwen Yang, as well as research associate Heather Schwartz-Narbonne.

Diamond says PFAS eventually end up in our bodies and the environment, where they stay.

“PFAS are complex, persistent and they don’t break down. Whatever molecule is manufactured today will be in the environment 100 years later,” says Diamond, noting these toxic chemicals are found in a host of everyday products and have been linked to adverse health effects, including an increase in cancer risk, thyroid disease, cholesterol levels and decreased immune response and fertility.

“The bottom line is, there’s too much PFAS in the world and not enough restrictions around their use,” she says. “We need to get serious about replacing these substances with safer alternatives if we want to protect our health, and our planet’s health.”

As an environmental chemist and chemical management expert, Diamond is on a scientific mission to determine the most significant sources of PFAS exposure and spur action to limit their prevalence. As she puts it, there would be no “forever” if these chemicals were never used in the first place.

Samples of paper bag and fibre bowl used for takeout food were tested for PFAS (images courtesy of Miriam Diamond)

Diamond saw her research help shape policy last fall when California banned the use of PFAS in fabrics and cosmetics by 2025. This legislation builds on recent studies about PFAS in clothing and makeup that were carried out by Diamond and her colleagues at 91�Թ� and institutions around the world.

In a first-of-its-kind paper published in September 2022, the researchers analyzed children’s clothing in Canada and the United States to determine if such apparel is a significant source of PFAS exposure.

They found extremely high levels of these chemicals in school uniforms, mittens and other products marketed as stain resistant. Diamond says because clothing is worn against the skin, there is a higher risk of absorbing and inhaling chemical contaminants – particularly fluorotelomer alcohols, the primary type of PFAS measured in the uniforms.

“We're running an experiment right now on kids’ exposure to PFAS. There's insufficient information on the harm posed by the chemicals that are going into these products,” Diamond says. “I don’t know any parent who values stain repellency over their child’s health.”

Diamond notes that PFAS management is becoming a priority in Canada. In 2021, Environment Canada announced it was gathering evidence to address designating PFAS as a class, rather than as individual compounds as part of the federal government’s chemicals management plan. Such designations are important for enabling efficient regulatory practices. The action includes investing in research such as Diamond’s to collect information about sources of the chemicals and levels in the environment through 2023.

“We know where PFAS is used, but we don’t know what the biggest sources of environmental and human contamination are,” Diamond says.

She adds that exposure science has shown high levels of these chemicals in personal care products. So, Diamond and the team investigated PFAS levels in cosmetics in 2021, testing 231 cosmetic products. They found the highest concentration of PFAS in foundations, mascaras and lip products – particularly those that were labelled “wear-resistant,” “long-lasting” or “waterproof.”

“Focusing our attention on cosmetics as a potentially significant route to PFAS was a no-brainer,” she says. “You’re putting them right on your skin, near your eyes, your tear ducts, on your mouth ... is your beauty worth the risk to your health?”

Next, she is turning her attention to building materials such as outdoor durable paints and sealants for concrete and wood, and textiles used in outdoor settings like patio furniture.

“The problem with PFAS is that it is not labelled as an ingredient, so if you want to limit your use of certain products that contain these chemicals, you usually don’t even know what these are,” says Diamond. “That’s when buzzwords will tip you off – like stain-resistant and waterproof. But this vigilance shouldn’t fall only to the consumer.

“In Canada, we need to strengthen chemicals management to improve the health and safety for ourselves and for the next generations. That means better corporate responsibility and government regulations.”

From happiness to health care, undergraduate summer program inspires future data scientists

Christopher.Sorensen — Thu, 18 Aug 2022 13:13:32 +0000

From happiness to health care, undergraduate summer program inspires future data scientists

Christopher.Sorensen Thu, 08/18/2022 - 09:13

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Victoria College's Anthony McCanny is exploring whether gross domestic product (GDP) is a good measure of economic and societal success as part of a Data Sciences Institute summer research program (photo courtesy of the Data Sciences Institute)

Chris Sasaki

Topic

Our Community

Data Sciences Institute

Temerty Faculty of Medicine

Artificial Intelligence

Computer Science

Dalla Lana School of Public Health

Laboratory Medicine and Pathobiology

Innis College

Psychology

St. Michael's College

Victoria College

What causes glacial periods to end? Can machine learning help make medical decisions? Can money buy happiness?

These were among the questions studied during the 2022 Summer Undergraduate Data Science (SUDS) Research Program run by the 91�Թ�’s hub for data science research: the Data Sciences Institute (DSI), based in the Faculty of Arts & Science.

The program pairs faculty members with undergraduate students from universities across Canada who are interested in data science careers.

“The DSI SUDS program is about inspiring the next generation of data scientists and giving undergraduate students an opportunity to explore data science as a career opportunity,” says Laura Rosella, the institute’s associate director of education and training and an associate professor at the Dalla Lana School of Public Health and in the Faculty of Medicine’s department of laboratory medicine and pathobiology.

“In addition to their research projects, these students are provided with a full set of data science networking, academic and professional development opportunities. And we couldn’t be more thrilled to have the chance to inspire them and hopefully kickstart their careers in this exciting field. They are truly an exceptional bunch.”

The variety of projects tackled in the program reflects the growing number of disciplines that are increasingly reliant on data skills and expertise. Three projects involving Faculty of Arts & Science faculty members and students addressed questions in psychology, Earth sciences and the intersection of machine learning and health care.

Students presented their research during the SUDS Research Day in August (photo courtesy of the Data Sciences Institute)

What causes ice ages to end?

Innis College student Tina Tsan is working with Ulrich Wortmann, an associate professor in the department of Earth sciences on an analysis of why the last ice age came to a sudden end.

During glacial periods, ocean levels dropped as water was taken up in glaciers. This exposed the continental shelf, triggering a chemical reaction that released large amounts of carbon dioxide into the atmosphere. Tsan and Ulrich’s analysis supports the idea that this CO2 may have warmed the atmosphere enough to end the last ice age.

“The work I'm doing in SUDS is an extension of my previous undergraduate research into changes in ocean chemistry,” says Tsan. “By exploring the data science side of this work, I now have a better understanding of my research and this gives me a solid foundation for the fall when I start my master’s degree in Earth sciences.

“For me, the biggest reward from the SUDS program has been how it’s broadened my perspective and understanding of what data science is and how it's used in different fields.”

Wortmann praised the program.

“The SUDS program is fantastic – especially for students who are not embedded in a large research group or who are working in a field where few of their peers have an interest in data science,” he said.

Can machine learning help make medical decisions?

A member of St. Michael’s College, Yingke Wang is working with Rahul Krishnan, an assistant professor in the department of computer science and the department of laboratory medicine and pathobiology in the Temerty Faculty of Medicine.

Krishnan’s research exists at the intersection of machine learning and health care. Among his lab’s projects: redesigning patient risk scores, which are metrics used in hospitals to predict aspects of a patient’s care and inform clinical decisions such as who should receive an organ transplant.

One of the ways such scores are evaluated is with a population simulator called LivSim, which simulates how a group of people might be affected by a specific choice of risk score.

“Yingke will be working to help optimize LivSim,” says Krishnan. “His work will get it operational and running efficiently, so we can evaluate the efficacy of some of the novel risk scores designed in the lab.

“It's been wonderful to see the support that SUDS provides to young scholars like Yingke. Introducing students to research early is an important step for them to see the opportunities that graduate study can provide."

Wang, similarily, says he has reaped significant rewards from the program.

“Thanks to SUDS, I’m learning how to combine machine learning algorithms in the health-care industry as well as explore survival analysis,” says Wang. “Plus, the self-learning skills I gain will be essential to me for approaching graduate study.”

Can money buy happiness?

Anthony McCanny, a member of Victoria College where he was a Northrop Frye Centre Undergraduate Fellow, is interested in whether gross domestic product (GDP) is a good measure of economic and societal success –and what type of government spending improves the lives of citizens.

He is working with Felix Cheung, an assistant professor in the department of psychology who studies the determinants and consequences of subjective well-being across diverse populations – including the question of whether economic growth translates into personal happiness.

“During SUDS, Anthony and I will study an age-old question: whether money buys happiness,” says Cheung. “We examine this question at a policy level by testing how governments can allocate their expenditures to best benefit citizens' well-being.

“Anthony is using a cutting-edge method to test this long-standing research question with the largest dataset on global happiness. The results hold promise to inform governmental expenditure, an extremely timely topic as many countries around the world are reprioritizing their spending given recent events such as the invasion of Ukraine.”

McCanny, for his part, says the program brought “learning, fun, joy and community” to his summer.

“I’ve been very lucky in Professor Cheung’s lab to have the freedom to conduct my own research, paired with great guidance,” he says. “It’s hard not to feel like this summer has redefined my path in life, filling me with enthusiasm for a career in research, and connecting me with people that I hope I get to keep working with.”

Earth sciences researchers locate billion-year-old groundwater in South Africa

Christopher.Sorensen — Tue, 16 Aug 2022 15:34:54 +0000

Earth sciences researchers locate billion-year-old groundwater in South Africa

Christopher.Sorensen Tue, 08/16/2022 - 11:34

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91�Թ� geochemist Oliver Warr collects a sample of groundwater in Moab Khotsong, South Africa, that is 1.2 billion years old (photo courtesy of Oliver Warr)

Faculty of Arts & Science Staff

Topic

An international team of researchers has discovered groundwater that is more than a billion years old deep below Earth’s surface – only the second time such a discovery has been made.

The water, which is 1.2 billion years old, was recovered from a gold- and uranium-producing mine in Moab Khotsong, South Africa, confirming that groundwater of such a vintage is more abundant than previously thought.

The find sheds new light on how life is sustained below Earth’s surface and how it may thrive on other planets.

“Ten years ago, we discovered billion-year-old groundwater from below the Canadian Shield – this was just the beginning, it seems,” says University Professor Barbara Sherwood Lollar of the department of Earth sciences in the 91�Թ�’s Faculty of Arts & Science and co-author of a study published in Nature Communications.

“Now, 2.9 kilometres below the Earth’s surface in Moab Khotsong, we have found that the extreme outposts of the world’s water cycle are more widespread than once thought.”

What’s different compared to the 2013 discovery at Kidd Creek Mine near Timmins, Ontario is that high local uranium levels made the find more of a challenge, as the mineral was obscuring the age of the water deep inside the subsurface rock.

Uranium and other radioactive elements naturally occur in the surrounding host rock that contain mineral and ore deposits. Understanding the role of these elements has revealed novel ways of thinking about groundwater’s role as a source of energy for rock-eating micro-organisms previously discovered in Earth’s deep subsurface. The micro-organisms draw chemical energy from the rock to flourish in the absence of sunlight.

When elements like uranium, thorium and potassium decay in the subsurface, the resulting alpha, beta, and gamma radiation has ripple effects, triggering radiogenic reactions in the surrounding rocks and fluids. The radiation also breaks apart water molecules in a process called radiolysis, producing large concentrations of hydrogen – an essential energy source for subsurface microbial communities that are unable to access energy from the sun for photosynthesis.

Researcher Oliver Warr collects samples 2.9 kilometers beneath the Earth’s surface (photo courtesy of Oliver Warr)

In the groundwater samples recovered from Moab Khotsong, the researchers found large amounts of radiogenic helium, neon, argon and xenon, and an unprecedented discovery of an isotope of krypton – a never-before-seen tracer of this powerful reaction history.

While the almost impermeable nature of the rocks where these waters are found means the groundwaters themselves are largely isolated and rarely mix – accounting for their 1.2-billion-year age – diffusion of hydrogen, helium and neon among other gases can still take place.

“Solid materials such as plastic, stainless steel and even solid rock are eventually penetrated by diffusing helium, much like the deflation of a helium-filled balloon,” says Oliver Warr, a research associate in 91�Թ�’s department of Earth sciences and lead author of the study. “Our results show that diffusion has provided a way for 75 to 82 per cent of the helium and neon originally produced by the radiogenic reactions to be transported through the overlying crust and captured for industrial applications.”

The researchers stress that the study’s new insights on how much helium diffuses up from deep inside Earth is a critical step forward as global helium reserves run out and the transition to more sustainable resources gains traction.

“For the first time, we have insight into how energy stored deep in Earth’s subsurface can be released and distributed more broadly through its crust over time,” says Warr. “Think of it as a Pandora’s box of helium-and-hydrogen-producing power, one that we can learn how to harness for the benefit of the deep biosphere on a global scale.

“Humans are not the only life-forms relying on the energy resources of Earth’s deep subsurface. Since the radiogenic reactions produce both helium and hydrogen, we can not only learn about helium reservoirs and transport, but we can also calculate the variability of hydrogen energy that can sustain subsurface microbes on a global scale.”

Warr notes that such calculations are vital for understanding how subsurface life is sustained on Earth, and what energy might be available from radiogenic-driven power on other planets and moons in the solar system and beyond – informing upcoming missions to Mars, as well as to Saturn’s moons Titan, Enceladus and Jupitor’s moon Europa. The findings hint at the possibility that subsurface water may persist on long timescales despite surface conditions that no longer provide a habitable zone.

The paper’s other co-authors include C.J. Ballentine from the University of Oxford, researchers from Princeton University and the New Mexico Institute of Mining and Technology. The research was supported by the Natural Sciences and Engineering Research Council of Canada, the Nuclear Waste Management Organization of Canada, the University of Oxford and the Canadian Institute for Advanced Research. The National Science Foundation and the International Continental Scientific Drilling Program funded the drilling and installation of sampling equipment.

The Earth's crust has been 'dripping' beneath the Andes Mountains for millions of years: Researchers

geoff.vendeville — Tue, 19 Jul 2022 15:41:12 +0000

The Earth's crust has been 'dripping' beneath the Andes Mountains for millions of years: Researchers

geoff.vendeville Tue, 07/19/2022 - 11:41

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Salar de Arizaro in the Atacama Desert (photo by Nicolas de Camaret, CC BY 2.0, via Wikimedia Commons)

Sean Bettam

Topic

Just like honey slowly dripping from a spoon, parts of the rocky outermost layer of Earth’s shell are continuously sinking into the more fluid layer of the planet’s mantle over the course of millions of years. Known as lithospheric dripping – named for the fragmenting of rocky material that makes up Earth’s crust and upper mantle – the process results in significant deformations at the surface such as basins, folding of the crust and irregular elevations.

Though the process is a relatively new concept in the decades-old field of plate tectonics, several examples of lithospheric drip around the world have been identified – the Central Anatolian Plateau in Turkey and the Great Basin in the western U.S., for two. Now, a team of researchers led by Earth scientists at the 91�Թ� has confirmed that several regions in the central Andes Mountains in South America were formed the same way.

And they’ve done so using materials available at any hardware store and art supplies outlet.

“We have confirmed that a deformation on the surface of an area of the Andes Mountains has a large portion of the lithosphere below avalanched away,” says Julia Andersen, a PhD candidate in the department of Earth sciences at 91�Թ� and lead author of a study published in Communications Earth & Environment, part of the Nature family of journals. “Owing to its high density, it dripped like cold syrup or honey deeper into the planetary interior and is likely responsible for two major tectonic events in the Central Andes – shifting the surface topography of the region by hundreds of kilometres and both crunching and stretching the surface crust itself.

“Overall, the results help define a new class of plate tectonics and may have implications for other terrestrial planets that do not have Earth-like plate tectonics such as Mars and Venus.”

A geological map of the Arizaro Basin, demonstrating folding and thrust faults within the basin, as compared with surface view of the experimental simulation of lithospheric dripping. Folding and direction of shortening is depicted with red arrows (left photo courtesy of DeCelles, et al.; right courtesy of Julia Andersen et al.)

Lithospheric dripping occurs when portions of the lowest layer of Earth’s outer shell thicken and begin to drip into the mantle below when warmed to a certain temperature.

As the fragments sink into the lower mantle, it first forms a basin at the surface which later springs up when the weight below breaks off and sinks further into the deeper depths of the mantle. This results in an upward bobbing of the land mass across hundreds of kilometres.

The Central Andean Plateau is defined by the Puna and Altiplano high plateaus and was first formed when the Nazca plate slid beneath the South American plate during the well-documented plate tectonics process of subduction, during which a portion of the heavier of two tectonic plates sinks into the mantle when they converge.

Past studies have suggested, however, that the subsequent rise of Central Andean topography has not been uniform in time but rather was built through sporadic pulses of uplift throughout the Cenozoic Era that began approximately 66 million years ago.

Geological estimates indicate that the relative timing and mechanism of uplift in the region and the styles of tectonic deformation are different between the Puna and Altiplano plateaus. The Puna Plateau is characterized by higher average elevation and includes several isolated inland basins, such as the Arizaro Basin and the Atacama Basin, and distinct volcanic centres.

“Various studies invoke removal of the lithosphere to account for the widespread, non-subduction related surface deformation and evolution of the plateaus,” says Earth sciences Professor Russell Pysklywec, co-author of the study and Andersen’s PhD supervisor. “Further, crustal shortening in the Arizaro Basin interior is well documented by folding and local thrust faults but the basin is not bounded by known tectonic plate boundaries, indicating there is a more localized geodynamic process occurring.”

Geoscientists have used the sedimentary rock record to track changes in surface elevation of the Central Andes since the Miocene epoch approximately 18 million years ago. Seismic imaging provides a remote image of Earth’s interior much like an ultrasound for a human body, illuminating a new view of the lithospheric drip structures.

A simulation of the rocky outermost layer of Earth’s shell using silicone polymer fluid, modelling clay, and a sand-like layer made from ceramic and silica spheres demonstrates the process of lithospheric dripping. (photo by Julia Andersen/Tectonophysics Lab/91�Թ�)

Andersen and her colleagues say past geological studies advance evidence for lithospheric drips in the region, but the dynamical processes of lithospheric dripping and their role in driving local surface tectonics in these purported geological cases are uncertain. For the most part, geodynamic model predictions have not been tested in the context of direct regional geological or geophysical observations.

So, the team set about developing analogue laboratory models with geological and geophysical constraints to recreate what happened over thousands of centuries and test their hypothesis that the topographic and tectonic evolution of hinterland basins of the Central Andes was caused by lithospheric drip processes.

“Recognizing the massive time and length scales involved in these processes – millions of years and hundreds of kilometres – we devised innovative three-dimensional laboratory experiments using materials such as sand, clay and silicone to create scaled analogue models of the drip processes,” Andersen says. “It was like creating and destroying tectonic mountain belts in a sandbox, floating on a simulated pool of magma – all under incredibly precise sub-millimetre measured conditions.”

The models were constructed inside a Plexiglass tank with a set of cameras positioned above and beside the tank to capture any changes. The tank was first filled with polydimethylsiloxane (PDMS) – a silicone polymer fluid approximately 1,000 times thicker than table syrup – to serve as Earth’s lower mantle. Next, the upper-most solid section of the mantle was replicated using a mixture of PDMS and modelling clay and put into the tank on top of the mantle. Finally, a sand-like layer made from a mixture of precision ceramic spheres and silica spheres was laid on top to serve as Earth’s crust.

The researchers activated the model by inserting a high-density seed into the PDMS and modelling clay layer, to initiate a drip that was subsequently pulled downward by gravity. The cameras outside the tank ran continuously, capturing a high-resolution image roughly every minute.

“The dripping occurs over hours so you wouldn’t see much happening from one minute to the next,” Andersen says. “But if you checked every few hours, you would clearly see the change – it just requires patience.” The study presents snapshots from every 10 hours to illustrate the progress of the drip.

The researchers then cross-referenced the size of the drip and the damage to the replica crust at select time intervals to see how their scaled processes matched up against the sedimentary records of the areas in question over millions of years.

Artist impressions of two types of lithospheric drip, supported by surface views of the experimental simulation of the processes. One produces thickening and uplift of Earth’s crust, while the other results in the formation of a basin at the surface (photo by Julia Andersen/Tectonophysics Lab/91�Թ�)

“We compared our model results to geophysical and geological studies conducted in the Central Andes, particularly in the Arizaro Basin, and found that the changes in elevation of the crust caused by the drip in our models track very well with changes in elevation of the Arizaro Basin,” Andersen says. “We also observed crustal shortening with folds in the model as well as basin-like depressions on the surface so we’re confident that a drip is very likely the cause of the observed deformations in the Andes.”

The researchers suggest the findings aim to clarify the link between mantle processes and crustal tectonics, and how such geodynamic processes may be interpreted with observed or inferred episodes of lithospheric removal. “The discoveries show that the lithosphere can be more volatile or fluid-like than we believed,” says Pysklywec.

Additional contributors to the study include Tasca Santimano, of 91�Թ�'s department of Earth sciences, and Oguz Göğüş at Istanbul Technical University and Ebru Şengül Uluocak at Çanakkale Onsekiz Mart University in Turkey.

The research was made possible thanks to support from a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada, the International Fellowship for Outstanding Researchers Programme of the Scientific and Technological Research Council of Turkey, a TUBITAK Fellowship for Visiting Scientists, as well as Compute Ontario and the Digital Research Alliance of Canada.

Researchers study plants sprouting from century-old seeds uncovered during Toronto Port Lands excavation

geoff.vendeville — Mon, 27 Jun 2022 20:23:53 +0000

Researchers study plants sprouting from century-old seeds uncovered during Toronto Port Lands excavation

geoff.vendeville Mon, 06/27/2022 - 16:23

Cutline

Forestry PhD candidate Melanie Sifton examines soil recovered from the Port Lands construction site (photo by Geoffrey Vendeville)

Chris Sasaki

Topic

Cell and Systems Biology

Cities

Ecology & Evolutionary Biology

Forestry

Graduate Students

John H. Daniels Faculty of Architecture

Undergraduate Students

University College

Victoria College

At a Toronto Port Lands construction site on the city’s waterfront, keen-eyed workers recently spotted plants that had sprouted from soil recently exposed by the removal of tonnes of earth. The plants were hard stem bulrush and cattails, which are commonly found in freshwater marshes.

Sarah Finkelstein and Shelby Riskin

Because the plants grew from a patch of ground that had been seven metres below the surface for a century, conservationists concluded that they had grown from seeds buried when Ashbridges Bay Marsh at the mouth of the Don River was covered with landfill in the early 1900s.

Now, a team of 91�Թ� researchers including Sarah Finkelstein and Shelby Riskin is studying the soil removed from the site for a better understanding of the long-lost natural habitat.

Finkelstein, a paleontologist and associate professor who is chair of the Faculty of Arts & Science’s department of Earth sciences, studies paleoenvironmental records to better understand past climates and how ecosystems respond to environmental change. Mrinmayee Sengupta, an undergraduate geography student and University College member, will be helping her analyze the Port Lands soil.

“Our first goal is to understand what the marsh looked like back then,” Finkelstein says. “We’ll try to answer questions like: What was the plant community like? What were the food webs like? What role did this marsh play ecologically on a local and regional scale?”

Meanwhile, Riskin, an assistant professor, teaching stream, in the department of ecology and evolutionary biology in the Faculty of Arts & Science, will study how changes in land use impact ecosystems and how those ecosystems can continue to function in the face of change. Stuart Ralston, an undergraduate student studying environmental science and a member of Victoria College, will be working with Riskin on the project.

“We'll look for evidence of the life in the marsh – shells, seeds, pollen – and hopefully get an idea of the biodiversity of those soils from 100 years ago and compare it to what we find in the wetland soils in the area today,” Riskin says.

“I’m quite curious as to what we will find. If there is going to be a viable seed bank of native plants in those soils, or if there’s evidence that it was already a degraded ecosystem 100 years ago.”

Plants sprouted from 100-year-old seeds on a Port Lands construction site (photo courtesy of Waterfront Toronto/Vid Ingelevics/Ryan Walker)

Ashbridges Bay Marsh was once a thriving natural ecosystem. But by the end of the 1800s it was suffering from sewage and pollution from Toronto’s waterfront cattle yards, among other sources. As the city grew in the early 20th century, it was covered over and more industry moved onto the new land.

Today, the Port Lands is undergoing major redevelopment to reduce flooding at the mouth of the Don River and to create parks and new wetlands. As workers dig, they are uncovering the city’s recent history like urban archeologists.

Soil samples from the Port Lands in 91�Թ�'s Earth Sciences Centre (photo by Geoffrey Vendeville)

The researchers will also measure the carbon content of the soil to understand whether it came from a natural source or human activity, and how well the marsh served to absorb and store carbon.

“Right now, my research group is working a lot on carbon uptake and sequestration in wetlands, which is an important research focus in Ontario given our abundance of wetlands and their potential role in mitigating climate change,” Finkelstein says. “This work could tell us how well this wetland functioned as a carbon sink. It will also help us learn more about wetland restoration and what we may be able to recreate on the Toronto waterfront.”

Guided by students and experts, 91�Թ� rolls out new approach to mental health services delivery

Christopher.Sorensen — Mon, 30 May 2022 13:57:57 +0000

Guided by students and experts, 91�Թ� rolls out new approach to mental health services delivery

Christopher.Sorensen Mon, 05/30/2022 - 09:57

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(Photo by David Lee)

Geoffrey Vendeville

Topic

Our Community

Health & Wellness Centre

Centre for Addiction and Mental Health

Lawrence S. Bloomberg Faculty of Nursing

Mental Health

Ontario Institute for Studies in Education

St. George

91�Թ� Mississauga

91�Թ� Scarborough

Undergraduate Students

University College

No wait times for mental health appointments at Health & Wellness. Redesigned health and wellness spaces, both virtual and physical, that make it easier for students to receive help when and where they need it. And, beyond campus, access to staff who can help students navigate mental health resources in the community.

These are among the many steps the 91�Թ� has taken, or that are underway, to improve the delivery of mental-health services across its three campuses in line with the sweeping recommendations made by Presidential and Provostial Task Force on Student Mental Health, which was composed of students, faculty and staff.

“You don't have to wait a month to see a counsellor,” said Joe Desloges, the provostial adviser on process redesign of mental health services, of the new “stepped care” model. “For those in need, you don't have to wait months to see a psychiatrist.”

The majority of the task force’s action items have already been completed or are in progress – with students continuing to play a key role in the systems’ redesign. They include Vishar Yaghoubian, a two-term undergraduate student representative on 91�Թ�’s Governing Council who canvassed student groups over eight months and synthesized their points of view in a report spanning more than 100 pages. Yaghoubian, a Woodsworth College student, called it a “long process,” but said the fact that university leaders have dedicated many months to hearing students’ concerns and soliciting recommendations are signs that 91�Թ� is truly listening.

Cheryl Regehr, 91�Թ�’s vice-president and provost, lauded the 91�Թ� community for its commitment to improving mental health service delivery on the three campuses.

“Across the university, our faculty, students, staff and librarians have been remarkably generous in sharing insights, ideas, experiences and recommendations that show how deeply they care about this issue,” Regehr said. “We’re especially grateful to our students for their contributions and their commitment to fostering compassion and community.

“Now, we are seeing the results of all that consultation and work come together as the 91�Թ� continues to roll out a new approach to mental health services delivery – one that will support students’ well-being and success at every turn.”

In a recent meeting of 91�Թ�’s senior leaders, Desloges and Andrea Levinson, director, psychiatric care at 91�Թ�’s Health & Wellness, provided an update on the university’s progress toward enacting all 21 of the task force’s recommendations.

A top priority of the task force, as well as all the campus Health & Wellness Centres, was to build an “easy access system” by implementing a “stepped care’ model of mental-health service delivery – a system where a range of resources and services are available to students, and where decisions about care are made based on students’ preference, need and the types of programming with which they are prepared to engage.

The 91�Թ� team engaged Stepped Care Solutions, a not-for-profit mental health consultancy group founded by Peter Cornish, now director of counselling and psychological services at the University of California, Berkeley, to help 91�Թ� transition to a more flexible and client-centric mental health-care model. Stepped Care’s 2.0 framework has been used by the Government of Canada in its COVID-19 response, as well as well as by jurisdictions such as Newfoundland and Labrador, Nova Scotia and the Northwest Territories.

“This system really supports a very diverse student body with wide-ranging needs and preferences,” said Levinson, an assistant professor of psychiatry in the Temerty Faculty of Medicine. “One key piece is that it’s strength-focused. We often see service delivery as trying to fix a problem, but this is about meeting students where they’re at and building on their inherent strengths and capacities.”

The model offers increased access to care at various degrees of intensity, with patients accessing different steps, in a flexible way, based on readiness, engagement and strengths. “The steps are based on choice and readiness rather than looking at traditional symptoms and functioning,” Levinson explained.

Crucially, the stepped care model emphasizes treatment over lengthy assessments, so that individuals can begin to receive the help they need sooner. In a presentation to 91�Թ� leadership, Cornish and Alexia Jaouich, vice-president program development and implementation at Stepped Care Solutions, said the framework helped reduce wait lists in provinces by more than 60 per cent.

While there may still be wait times for certain specialized services such as group psychotherapy under the new model, students don’t have to wait long for an initial appointment, said Desloges, a professor in the departments of geography and Earth sciences in the Faculty of Arts & Science.

In cases with more complex and urgent care needs, students on the St. George Campus will have access to mental-health navigators – in partnership with the Centre for Addiction and Mental Health (CAMH) – to guide them to and from acute care services in the hospital system.

“The navigators will be embedded within CAMH to support our students specifically in a setting that is often described as very overwhelming, confusing and hard to navigate,” Levinson said, adding that it’s the first time the system is being applied to a post-secondary context.

The university is also taking a phased approach toward recruiting navigators who would serve 91�Թ� Scarborough and 91�Թ� Mississauga in partnership with local hospital networks. And 91�Թ� has begun a search for an executive director, student mental health systems, policy and strategy – a new role overseeing mental health services across the three campuses. “Think of it as quality assurance across the whole institution to ensure consistency of information, accessibility, communications, branding and to lead outreach,” Desloges said.

As part of the redesign, service providers across the three campuses have completed cultural sensitivity and literacy training, and many have shared their biographies and specializations online so students can find a counsellor who is the right fit.

Jodie Glean, 91�Թ�’s executive director, equity, diversity and inclusion, said such initiatives are inextricably linked with the goal of creating a “culture of caring” across the university, a priority frequently mentioned in the task force’s report.

“The EDI landscape is continuously giving us tools, policies, initiatives to help mitigate the experience of -isms, discrimination and harassment on our communities,” Glean said. “But as well, it supports the notion of creating a culture of care because it gives us spaces to listen, learn and then develop our services and programs in a way that accounts for the fullness of who people are.”

The improvements to mental health services haven’t just been concerned with personnel but also spaces – both virtual and in-person.

Prior to the task force’s report, faculties, divisions and campuses listed their mental health resources separately, but they can now all be found at mentalhealth.utoronto.ca. The online mental health wayfinder, Navi (short for navigator), helps students discover available resources at the university and make personal decisions about appropriate supports. The tool is accessible 24/7 and communication is anonymous.

At the same time, Desloges noted that mental health service areas on all three campuses are undergoing renovation. On the St. George campus, the Koffler Student Services Centre, on the northwest corner of College and St. George Streets, is undergoing a planned modernization that begins this fall. The project will consolidate health and wellness services on a single floor and will add levels, ramps and an elevator to improve accessibility. During the expansion – expected to take two and a half years – health and wellness services on St. George will move to 700 Bay Street, a site chosen for its proximity to campus.

At 91�Թ� Scarborough, a new, five-storey hub on the north side of the campus, the Instructional Centre 2, will have a floor dedicated to health and wellness, along with airy lounges, glass facades and a green roof. The new Health & Wellness Centre will be equipped with areas designed for exercise, meditation, decompression, baby feeding and relaxation. “The presence of a highly visible student service centre will create an inclusive and accessible hub for student supports,” said Sheila John, acting dean, student experience and wellbeing at 91�Թ� Scarborough.

At 91�Թ� Mississauga, the Health & Counselling Centre (HCC), on the first level of the William G. Davis Building, is in the midst of a renovation of its counselling and medical suites. Once the project is finished, the suites will be facing each other and share a lounge to better integrate care. The counselling suite, which was completed first, is due to reopen this summer, while renovations at the medical clinic are slated to begin this fall.

“This has allowed us to expand the number of counselling staff and mental health navigation and triage staff,” said Erin Kraftcheck, medical director of the HCC. “It has also allowed our counselling rooms to be remodeled so that they are bright and spacious, to assist with setting a tone of wellness for student clients.”

Students’ input may shape, indirectly, the future of mental health services at 91�Թ� and beyond another way: through research.

Lexi Ewing, a fourth-year PhD student in developmental psychology and education at the Ontario Institute for Studies in Education, was among the students who lent their expertise and experience as advisers to a student and youth mental health research initiative called Inlight, which is led by Kristin Cleverley, an assistant professor in the Lawrence S. Bloomberg Faculty of Nursing.

Ewing provided feedback on the stepped care model, mental health website and on the role of special constables when responding to mental health calls.

“What makes this research so important is there is so much work that needs to be done – a lot of nuanced contexts need to be investigated further and more in depth,” she said.

“I tend to think of post-secondary student mental health as an emerging field of literature.”

For her dissertation, Ewing is looking at how stressors associated with a stage in life researchers call “emerging adulthood” sometimes overlap with the transition to university to produce unique challenges. “We don’t really know how those things interact and create kind of unique risks for the development of mental health concerns,” she said.

91�Թ�’s new stepped model of care, along with other changes like the mental health navigators and streamlined website, are all positive developments, according to Ewing.

“With the redesign, one of the big things was ensuring timely access to care and appropriate care,” she said.

“I do think the stepped care model that is being implemented will help to really address that. I think it’s really structured so that it can meet students where they are at the right time.”

'Working with the Earth': 91�Թ�'s Andrei Swidinsky finds climate change solutions beneath our feet

Christopher.Sorensen — Thu, 03 Mar 2022 16:24:24 +0000

'Working with the Earth': 91�Թ�'s Andrei Swidinsky finds climate change solutions beneath our feet

Christopher.Sorensen Thu, 03/03/2022 - 11:24

Cutline

Andrei Swidinsky says geophysical technology can help address climate change by finding sources of geothermal energy, locating of minerals critical for green-energy technologies and identifying sites for carbon storage (photo courtesy of Swidinsky)

Topic

Sustainability

Perhaps the most unusual use of geothermal energy that 91�Թ� geophysicist Andrei Swidinsky ever encountered was at the Colorado Gators Reptile Park in southern Colorado.

In the 1970s, the owners of the site began farming tilapia in ponds warmed to 32 C by water they had tapped into below ground. In the 1980s, they purchased 100 baby alligators to help dispose of the fish remains generated by their operation. Before long, the alligators had grown to full size, people were willing to pay to see them and a unique and unexpected tourist attraction was born.

Swidinsky was an assistant professor at the Colorado School of Mines at the time, and the farm and the use of small-scale geothermal heating systems in rural Colorado made a lasting impression on him.

“Before that, I’d thought geothermal was only something used for electrical power generation from large-scale systems like those in Iceland,” says Swidinsky, who did his PhD at 91�Թ� and is now an associate professor and Teck Chair in Exploration Geophysics in the department of Earth sciences in the Faculty of Arts & Science.

“But Colorado has nowhere near the geothermal resources of Iceland, and yet a lot of the town where I ran my geophysical field course, Pagosa Springs, was heated with small-scale geothermal systems. So, I saw that if you’re really smart about using geothermal resources, you can do a lot.”

Swidinsky’s research focus is geophysical exploration – in particular, developing geophysical imaging technology to help understand what lies beneath the Earth’s surface. The approach includes seismic and electromagnetic techniques for mapping subsurface structure, temperature and physical characteristics or lithology.

Swidinsky says geophysical technology has enormous potential to address what he describes as “the greatest challenge that global society currently faces: climate change.” It can do this by helping to develop conventional and enhanced geothermal energy generation, locate reserves of green energy-enabling critical minerals and help build carbon storage capacity in Canada.

Swidinsky’s attention turned to climate change when he returned to Canada from Colorado in 2019 to take a visiting professorship position in the department of Earth sciences. It was the year of a federal election and the debate around jobs, oil, the economy and achieving net-zero carbon emissions was going full bore. After another stint in Colorado, he returned to 91�Թ� and was determined to use his expertise in geophysical exploration to address the global crisis.

“Canada isn’t on target to reach its goal of net-zero emissions by 2050,” says Swidinsky. “But I think we can do it, and I think technological innovation is going to get us there.”

The geophysical exploration toolkit Swidinsky is working on will improve exploration for geothermal sources of energy by measuring the electrical conductivity and density of rock – both of which are correlated to structure, temperature and lithology. This exploration will help find heated, subsurface water; it can also identify potential sites for enhanced geothermal systems where water pumped through heated rocks is used to drive energy-generating turbines. What’s more, a clearer understanding of these heat sources will help manage them safely once developed.

The toolkit will also help on another climate change front by improving our ability to find minerals critical to green energy – for example, lithium and cobalt for batteries used in electric vehicles, and rare earth elements needed for wind turbines.

“The question is: Can the technologies developed for base and precious metal exploration in Canada now be used to find lithium and cobalt?” says Swidinsky. “I think the answer is yes.”

Finally, this same sub-surface imaging can identify the storage sites to help cope with the carbon produced in Canada every year.

“There are some storage sites out west,” says Swidinsky, “But we produce over 500 million tons of carbon in Canada every year and these types of operations need to be scaled up enormously. We're not just talking about doubling capability, or increasing it by a factor of 10 – we're talking about expanding it by a factor of a thousand or more.”

Despite the challenges, Swidinsky has a vision of a sustainable future that considers the reality that, in his estimation, Canada will still be generating some energy from fossil fuels in 2050.

“There probably aren’t the geothermal and other renewable energy resources in the country to give us all the electricity we need,” he says. “So, my vision is that a portion of our energy comes from green and clean-energy sources. meaning that if you have electric vehicles running on clean energy, you have no emissions.

“But in 2050, we’re likely going to be burning fossil fuels to some extent – not just in Canada but globally. What I envision is that those emissions can be captured and we can store them using innovative technologies. With geothermal, nuclear, wind and solar energy – and carbon capture – we can achieve net zero.

“By working with the Earth, we can make that vision a reality and solve climate change.”

Massive new animal species discovered in half-billion-year-old Burgess Shale

Christopher.Sorensen — Wed, 29 Sep 2021 19:22:51 +0000

Massive new animal species discovered in half-billion-year-old Burgess Shale

Christopher.Sorensen Wed, 09/29/2021 - 15:22

Cutline

Titanokorys gainesi was a giant compared to most animals that lived in the seas during the Cambrian period, most of which barely reached the size of a pinky finger (illustration by Lars Fields/Royal Ontario Museum)

ROM/A&S News Staff

Topic

Ecology & Environmental Biology

Graduate Students