The work may help answer a fundamental question about our planet and could hold clues as to the formation of other planets, according to lead author Jesse Reimink, assistant professor of geosciences.

“The dominating theory points to an inflection point some 3 billion years ago, implying we had a stagnant lid planet with no tectonic activity before a sudden shift to tectonic plates,” Reimink said. “We’ve shown that’s not the case.”

To chart the formulation of the Earth’s crust—or the crustal growth curve—researchers turned to more than 600,000 samples comprising the Earth’s rock records database. Researchers across the globe—including at Penn State—have analyzed each rock sample in the record to determine geochemical contents and age. Researchers chose the rock records over mineral samples, which informed the theory of a more sudden formation, because they said the rock record is more sensitive and less prone to bias on those time scales.

Knowing that the reliability of the mineral record decreases through time, researchers recreated the crustal growth curve using the rock records. To do that, they developed a unique method for determining how igneous rocks dating to millions of years ago were reworked and reformed over time: experimentally demonstrating how the same rock could change in different ways over time. Rocks can be reformed a number of ways, such as weathering into sediments or being remelted in the mantle, so researchers used this experimental data to inform novel mathematical tools capable of analyzing the rock records and working out the differences in sample changes. 

“We calculated how much reworking has happened by looking at the composition of igneous rocks in a new way that teases out the proportion of sediments,” Reimink said. 

They used these calculations to calibrate the reworking documented in the rock records. Then, researchers calculated Earth’s crustal growth curve using the new understanding of how the rocks were reformed. They compared the newly calculated curve to the rate of growth gleaned from mineral records by other experts. 

Reimink and his team’s work indicates the Earth’s crust follows the path of the mantle—the layer on which the crust sits—suggesting a correlation between the two. It’s not the first time geoscientists have suggested a more gradual crustal growth, Reimink said; however, it’s the first time the rock record has been used to back it up. 

“Our crustal growth curve matches the mantle record of growth, so it seems like those two signals are overlapping in a way that they did not when using the mineral record to create the crustal growth curve,” Reimink said. 

Reimink cautioned that the research improves on what researchers understand, but it’s not the be-all and the end-all for crustal growth research. There are simply too few data points to speak to the vast time and space of the Earth’s crust. However, Reimink said, further analyzing the existing data points may help inform investigations of other planets. Venus, for example, has no tectonic plates and could be a modern day example of early Earth. 

“When did Earth and Venus become different?” Reimink asked. “And why did they become different? This crustal growth rate plays into that a lot. It tells the how, what and why of how planets evolved on different trajectories.” 

Joshua Davies, of the University of Quebec at Montreal; Jean-François Moyen, of the University of Lyon, France; and D. Graham Pearson, of the University of Alberta, Canada, contributed to this research. 

The Natural Sciences and Engineering Research Council of Canada supported this research in part. 

University students in science and engineering are increasingly aware of the importance of the need to have data visualization and communication skills. Regardless of their future career choices, they understand that data skills are key. 

However, few STEM majors include data visualization in their curricula. Higher education typically only offers students seminars on how to design a good research poster and students are, for the most part, left to learn data visualization skills on their own.

Graduate students who generate their own data also tend to perform more advanced data analysis and have complex stories to tell with their data. Often, they are working with datasets that hold many dimensions, lots of nuance, or uncertainty. Learning about data visualization at that level is as much about design as it is about science communication: distilling the key messages of one’s research and making difficult decisions about what content should be sacrificed at the altar of good design and a clear message. 

Antonia Hadjimichael, assistant professor of geosciences, sought to address that need. She developed the Data Viz for Scientists and Engineers course, designed to provide undergraduate and graduate students in the college with a design and communication foundation. 

“Personally, data visualization and visual communication in general has become increasingly important in my work,” Hadjimichael said. “I study climate impacts on water resources and planning for the future, which often requires the exploration of large simulation modeling experiments and large datasets with many dimensions. This has pushed me to be more inventive and thoughtful with how I communicate my scientific results. I have seen direct benefits from becoming a better visual communicator in my conference posters or talks. These are skills I want my own graduate students to pick up, but also, as an educator, I felt it important that new crops of students get some formal training on this.”

Hadjimichael spent more than a year conceptualizing this class and taught it for the first time during the spring 2023 semester. 

“My vision from the beginning was to teach all I would want someone else to teach me when I was in college,” Hadjimichael said. “Some of it was very fundamental to design in general, like use of color and how some color scales match different types of data better than others. Some of it was very practical to what STEM jobs entail—in academia or industry. For example, how to save Python figures into scalable vector images instead of raster images, or how to guide your audience through a complex graphic using animations and annotations in PowerPoint. Some of it was just about getting them to be visually creative, even if we don’t know how to get there yet with coding or software skills.”

The students who took the course were in the physical sciences and most had no prior background on design or aesthetics, nor did they have advanced web coding skills, but they wanted to learn just enough to be better visual communicators. 

“While my students’ backgrounds made planning the course more challenging, it kept the course focused on just the key skills that are most directly useful to scientists and engineers: coding simple analysis and charts in Python and creating more complex visualizations and infographics in Adobe Illustrator.” Hadjimichael said. “The goal was to stretch them a little on Python and also introduce them to some practical aspects of using software like Illustrator.” 

Another dimension that strongly shaped the class was constructive criticism and feedback during the process of making the visuals, emphasizing growth more than strictly defined “correctness”. 

“In most STEM education, students deliver an assignment and receive back a grade, with some instructor comments on what was wrong,” Hadjimichael said. “There’s little space for exploring weird ideas or being creative in a way that’s not formulaic. So, I wanted to emphasize a growth mindset and give the students a space to explore and try out design ideas in a low-stake environment before they submitted their final project.” 

This process turned the classroom into a learning community where every student came to understand that the creative process is messy and iterative—and it is through this iteration that we learn from our audience about what works. 

“Even though the final products were graded on having applied design principles from the class, all other homework was assessed on the basis of showing growth instead of perfection,” Hadjimichael said. “For example, demonstrating how they used feedback and on the quality of feedback they gave their peers.” 

Hadjimichael said this classroom environment was a great introduction to real-life situations, where data visualization practitioners lean on a supportive community as they practice and refine their skills. 

“From conversations with the students, they saw the feedback element of this class as essential to their growth and success,” Hadjimichael said. “When reflecting on this experience, this course design approach allowed for deeper and more meaningful learning, through building a sense of community and belonging. I loved how open and comfortable students were to express their thoughts, even if critical, about the designs and how they appreciated the importance of self-improvement and helping others.

Article is an excerpt taken from an article written by Antonia Hadjimichael and published in Nightingale Magazine, the journal of the Data Visualization Society. https://nightingaledvs.com/weaving-data-viz-into-science-and-engineering-education/ 

More than half of all plant species went extinct at the end of the Cretaceous period, according to new analysis that could influence modern conservation efforts. Sixty-six million years ago, an asteroid the size of San Francisco crashed into a shallow sea off the coast of modern-day Mexico and plunged the world into an extinction event that killed off as much as 75 percent of life, including the dinosaurs. 

But a debate remains about how the Cretaceous-Paleogene extinction (K-Pg) impacted plant life on land, in part because global studies of the fossil record have shown that no major plant families went extinct. A new analysis of emerging fossil data from North and South America sheds light on how plants fared during the K-Pg boundary and points to a true plant extinction. 

“There has been a trend in the literature to say maybe this event was bad for the dinosaurs and lots of marine life, but it was fine for plants because the major groups survived,” said Peter Wilf, professor of geosciences at and lead author. “Our review counters that idea, because everywhere we looked, more than half of the species went extinct.” 

New analysis of data from the Curiosity rover reveals that much of the craters on Mars today could have once been habitable rivers. 

“We’re finding evidence that Mars was likely a planet of rivers,” said Benjamin Cardenas, assistant professor of geosciences and lead author on a new paper announcing the discovery. “We see signs of this all over the planet.” 

In a study published in Geophysical Research Letters, the researchers used numerical models to simulate erosion on Mars over millennia and found that common crater formations—called bench-and-nose landforms—are most likely remnants of ancient riverbeds.

Rocks, rain and carbon dioxide help control Earth’s climate over thousands of years—like a thermostat —through a process called weathering. A new study led by Penn State scientists may improve our understanding of how this thermostat responds as temperatures change. 

“Life has been on this planet for billions of years, so we know Earth’s temperature has remained consistent enough for there to be liquid water and to support life,” said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences. “The idea is that silicate rock weathering is this thermostat, but no one has ever really agreed on its temperature sensitivity.” 

Because many factors go into weathering, it has been challenging to use results of laboratory experiments alone to create global estimates of how weathering responds to temperature changes, the scientists said. 

The team combined laboratory measurements and soil analysis from forty-five soil sites around the world and many watersheds to better understand weathering of the major rock types on Earth and used those findings to create a global estimate for how weathering responds to temperature. 

Their model may be helpful for understanding how weathering will respond to future climate change, and in evaluating man-made attempts to increase weathering to draw more carbon dioxide from the atmosphere—like carbon sequestration.

Kate Freeman, Evan Pugh University Professor of Geosciences, Christopher House, professor of geosciences, and Allison Baczynski, associate research professor of geosciences, have been selected to join the NASA Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission to analyze samples from the asteroid Bennu. 

As part of the Participating Scientist Program, the team will receive just over $1 million over three years to measure the abundances of stable isotopes in organic matter and organic molecules contained within the samples. Their work will help scientists learn about the formation of the solar system and about molecules that may have contributed to the development of life on Earth. 

“Isotope and molecule studies were already planned as part of the OSIRIS-REx mission, but what Penn State brings to the project is the ability to do the analyses with much smaller quantities than is possible using commercial instruments,” Freeman said. “We’ve developed methods in our lab that take us down orders of magnitude, so we can measure much smaller amounts of sample, which is perfect when all you have is a sugar packet-size of sample.” The research is supported by NASA.

When the ground rumbles in Antarctica, it may be an icequake—like an earthquake but caused by the movement of ice, not rock. A new study led by Penn State researchers found that these seismic events are driven by ocean tides at a major ice stream in West Antarctica. 
 

Seismic monitors captured more than 2,200 icequakes over a five-year period at the Foundation Ice Stream in West Antarctica. Ice streams are fast-flowing regions of ice that act like a drainage system carrying ice from the land to the ocean. The scientists found that the icequakes largely occurred during spring tides, which follow a new or full moon and are characterized by larger tide height range. 

“Tides are driven by the orbits of the moon and Earth, and it’s fascinating to be able to make a connection between tides and ice processes on Earth,” said Erica Lucas, who conducted the research while earning her doctorate in geosciences from Penn State. 

They found the large majority of the icequakes at the Foundation Ice Stream occurred around the grounding line—the zone where the ice sheet transitions from sitting on bedrock to floating on the ocean. These floating ice shelves act as buttresses, preventing land ice from flowing into the ocean, so understanding the processes happening in these regions is especially important, the scientists said. 
 

“If we can better understand the physical processes of ice flow then that’s another piece of the puzzle in understanding ice mass loss from Antarctica,” Lucas said. “Observing these icequakes at the Foundation Ice Stream may be one piece of the bigger puzzle.” 

Previous studies of tidal impacts on ice at the grounding line have relied on smaller datasets. The researchers benefited from a longer-term dataset collected on the Polar Earth Observing Network (POLENET). POLENET is a National Science Foundation-funded network of GPS and seismic stations installed across Antarctica. 

“This study, although focused on just one ice stream in Antarctica, points to the growing importance of icequakes for investigating grounding line processes and understanding the dynamics of glaciers,” said Andrew Nyblade, professor and head of geosciences, co-author of the study, and Lucas’ adviser. 

Using the data, the scientists observed a distinct seasonal shift in the time of day the seismic events occurred and that this was best attributed to the shift in the timing of daily high tide throughout the year. They reported their findings in the Journal of Geophysical Research: Earth Surface. 

The icequakes may be caused as stress accumulates between ice and bedrock on the steep hillslope located near the grounding line, the scientists said. As the tide rises, ice is being pushed upward, causing stress to build and then release, or slip. This process is known as “stick-slip.” 

“The Schmidt Hills slope, adjacent to the grounding line of the Foundation Ice Stream, may be an especially favorable location for seismic activity because the slope may sit above the water level at low tide and become a drier surface,” Lucas said. 

The scientists said further work could involve placing seismometers directly at the site to gather more precise data. 

“I think it’s exciting to find icequakes in new places,” Lucas said. “They could be happening all over, and we just don’t have instruments to observe them. So whatever information that we can pull from the data that we already have is very important.” 

Also contributing were Richard Aster, professor, Colorado State University; Douglas Wiens, professor, Washington University in St. Louis; Terry Wilson, professor emeritus, Ohio State University; and Audrey Huerta, associate professor, Central Washington University. The National Science Foundation supported this work.