Tag Archive for Earth and Environmental Sciences

Herbst and Greenwood in The Conversation: The Tell-Tale Clue to How Meteorites Were Made

Wesleyan faculty frequently publish articles based on their scholarship in The Conversation US, a nonprofit news organization with the tagline, “Academic rigor, journalistic flair.” In a new article, John Monroe Van Vleck Professor of Astronomy Bill Herbst and Assistant Professor of Earth and Environmental Sciences James Greenwood write about the model they’ve proposed for how the most common kind of meteorites form—a mystery that has dogged scientists for decades.

The tell-tale clue to how meteorites were made, at the birth of the solar system

April 26, 1803 was an unusual day in the small town of L’Aigle in Normandy, France – it rained rocks.

Over 3,000 of them fell out of the sky. Fortunately, no one was injured. The French Academy of Sciences investigated and proclaimed, based on many eyewitness stories and the unusual look of the rocks, that they had come from space.

The Earth is pummeled with rocks incessantly as it orbits the Sun, adding around 50 tons to our planet’s mass every day. Meteorites, as these rocks are called, are easy to find in deserts and on the ice plains of Antarctica, where they stick out like a sore thumb. They can even land in backyards, treasures hidden among ordinary terrestrial rocks. Amateurs and professionals collect meteorites, and the more interesting ones make it to museums and laboratories around the world for display and study. They are also bought and sold on eBay.

Despite decades of intense study by thousands of scientists, there is no general consensus on how most meteorites formed. As an astronomer and a geologist, we have recently developed a new theory of what happened during the formation of the solar system to create these valuable relics of our past. Since planets form out of collisions of these first rocks, this is an important part of the history of the Earth.

This meteor crater in Arizona was created 50,000 years ago when an iron meteorite struck the Earth. It is about one mile across. W. Herbst, CC BY-SA

This meteor crater in Arizona was created 50,000 years ago when an iron meteorite struck the Earth. It is about one mile across. (Photo by Bill Herbst, CC BY-SA)

The mysterious chondrules

Wesleyan in the News

In this recurring feature in The Wesleyan Connection, we highlight some of the latest news stories about Wesleyan and our alumni.

Wesleyan in the News

  1. Inside Higher Ed: “The Need for a Recovery of the Humanities”

In this essay, President Michael S. Roth responds to the “flood of negativity” in public discourse about higher education, in general, and the humanities, in particular. He suggests that “in order to recover the trust of students and their families, we must overcome our cultivated insularity.”

2. NBC News: “Carbon Dioxide Hits a Level Not Seen for 3 Million Years. Here’s What That Means for Climate Change — And Humanity.”

Dana Royer, professor and chair of earth and environmental sciences, comments on new evidence that the concentration of carbon dioxide in Earth’s atmosphere has climbed to a level last seen more than 3 million years ago. According to the article, shorter term impacts include loss of vegetation and sea-ice coverage, while other things, like the melting of ice sheets in Antarctica and Greenland, will occur more slowly. “But these impacts are going to persist for a very long time,” said Royer. “Once that happens, we can’t really reverse it.”

Students Study Volcanic Soil, Map Historic Footprints in Hawai’i as Part of Their Senior Capstone Projects

 Left to right: Tim Ku (faculty), Celeste Smith, Jacqueline Buskop, John Sheffer, Ryan Nelson, Sara Wallace-Lee, Kelly Lam, and Phil Resor (faculty) at a newly formed black sand beach on Hawaii. The rocks on the left solidified in 2018.

At left, Associate Professor of Earth and Environmental Sciences Tim Ku, Celeste Smith ’19, Jacqueline Buskop ’19, John Sheffer ’19, Ryan Nelson ’19, Sara Wallace-Lee ’19, Kelly Lam ’19, and Associate Professor of Earth and Environmental Sciences Phil Resor visit a newly formed black sand beach on Hawai’i. The rocks on the left solidified in 2018.

Six students majoring in earth and environmental sciences who said “aloha” to Hawai’i in January have completed their senior capstone project.

Seniors Jackie Buskop, John Sheffer, Kelly Lam, Sara Wallace-Lee, Ryan Nelson, and Celeste Smith traveled to the Big Island of Hawai’i Jan. 8-15 to conduct original, field-based research projects. They were accompanied by Associate Professors of Earth and Environmental Sciences Tim Ku and Phil Resor.

Prior to the trip, all six students enrolled in the fall semester course Senior Seminar E&ES 497, where they used the primary scientific literature to create hypothesis-driven research proposals. After collecting data in Hawai’i, the students enrolled in E&ES 498, where they analyzed and interpreted their data, and summarized their projects in journal article–style reports. On April 7, the students presented their results in short talks at the E&ES colloquium.

“Through this capstone sequence, students learn to develop and execute a research project from the initial idea through the planning, field collection, and data interpretation stages, and finally, how to synthesize this work into an illuminating presentation and written report,” Ku said. “We hope this capstone experience helps students transition to independent, professional scientists.”

Buskop, Sheffer, and Smith teamed up to work on a project titled “Inferences from 3D Modeling and Field Measurements of Human Footprints of the Ka’u Ash Desert (Kilauea, Hawai’i).”

O’Connell in The Conversation: 60 Days in Iceberg Alley, Drilling for Marine Sediment to Decipher Earth’s Climate 3M Years Ago

Wesleyan faculty frequently publish articles based on their scholarship in The Conversation US, a nonprofit news organization with the tagline, “Academic rigor, journalistic flair.” In a new article, Professor of Earth and Environmental Sciences Suzanne O’Connell writes about her work on board the JOIDES Resolution research vessel in the Scotia Sea, drilling for sediment core samples to study how much and how fast the Antarctic ice sheets melted between 2.5 to 4 million years ago, the last time atmospheric CO2 was at the same level as today. 

60 days in Iceberg Alley, drilling for marine sediment to decipher Earth’s climate 3 million years ago

Competition is stiff for one of the 30 scientist berths on the JOIDES Resolution research vessel. I’m one of the lucky ones, granted the opportunity to work 12-hour days, seven days a week for 60 days as part of Expedition 382 “Iceberg Alley” in the Scotia Sea, just north of the Antarctic Peninsula.

I’m a paleooceanographer. My research focuses on how Earth’s oceans and climate operated in the past; I’m especially interested in how much and how fast the Antarctic ice sheets melted between 2.5 to 4 million years ago, the last time atmospheric carbon dioxide levels were about 400 parts per million, as they are today. This work depends on collecting sediment samples from the ocean floor that were deposited during that time. These sediment layers are like a library of the Antarctic’s past environment.

The JOIDES Resolution is the only ship in the world with the drilling tools to collect both soft sediment and hard rock from the ocean – material that we recover in long cylinders called cores. No wonder researchers from all over the world, at all career stages, are excited to have traveled from India, Japan, Korea, the Netherlands, Germany, Spain, Switzerland, Brazil, China, Germany, Australia, the United Kingdom and, of course, the United States to join the expedition.

Study by Herbst, Greenwood Presents New Theory on How Meteorites Formed

A paper by John Monroe Van Vleck Professor of Astronomy William Herbst and Assistant Professor of Earth and Environmental Sciences James Greenwood will be published in the September 2019 issue of Icarus, published by Elsevier. The paper is available online.

The paper, titled “Radiative Heating Model for Chondrule and Chondrite Formation,” presents a new theory of how chondrules and chondrites (the most common meteorites) formed. It suggests a new approach to thinking about these rocks that populate the meteorite collections on Earth. It includes both theory and experiments (completed in Greenwood’s lab in Exley Science Center).

These laboratory experiments demonstrate that porphyritic olivine chondrules, the most voluminous type of chondrule, can be made using heating and cooling curves predicted by the “flyby” model. View a schematic diagram here.

“The problem of how chondrules and chondrites formed has been around for decades—more than a century, really. We cannot yet claim to have solved the problem but we have provided a new idea about the solution that passes many tests,” Herbst explained.

The basic idea, Herbst said, involves heating of small fluffy “rocks” in space as they fly past molten lava eruptions on larger asteroids, during the first few million years of the solar system’s existence.

Herbst, Greenwood, and Postdoctoral Research Associate Keniche Abe, will present this research at meetings this summer in Europe and Japan.

Varekamp Presents Papers at Volcanic Lakes Meeting in New Zealand, Receives Award

Johan (Joop) Varekamp

Joop Varekamp

Johan (Joop) Varekamp, the Harold T. Stearns Professor of Earth Science, presented three papers during the Commission on Volcanic Lakes (CVL) program held March 18-20 in Taupo, New Zealand. The papers were coauthored by Wesleyan students, graduate students, recent alumni, and faculty.

The CVL is a scientific, nonprofit organization of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI), connecting researchers that seek to understand how volcanic lakes relate to volcanic activity and their hazards.

Varekamp, who also is the Smith Curator of Mineralogy and Petrology of the Joe Webb Peoples Museum of Natural History and professor of earth and environmental studies, is a former leader of the CVL organization. In addition to delivering a keynote address, Varekamp was named the recipient of the 2019 IAVCEI Kusakabe Award.

Fish Species Named After Professor Barry Chernoff

Bryconops chernoffi

Bryconops chernoffi

A new species of fish discovered in Brazil was recently named in honor of Wesleyan Professor Barry Chernoff.

Barry Chernoff

Scientists encountered the Bryconops chernoffi in Rio Ipixuna—a small tributary of the Rio Maicuru, which feeds into the lower Amazon River in Pará, Brazil. Samples of the fish were collected by researchers on four trips in 2014–15, and in March 2019, Zootaxa released an article describing the new species.

Chernoff, the Robert Schumann Professor of Environmental Studies, focuses his research on freshwater fishes in North America and the Neotropical region, primarily those in South America in the Amazon.

He’s also professor of earth and environmental sciences; professor of biology; chair, Environmental Studies Program; and director of the College of the Environment.

The Zootaxa announcement explains that Bryconops chernoffi’s specific epithet honors “Barry Chernoff, and is in recognition for his contributions to the taxonomy of Bryconops, as well as for ichthyology as a whole.”

Chernoff has published 89 peer-reviewed scientific works, including six books and edited volumes. He has led international teams on expeditions designed to conserve large watersheds of the world, having made more than 34 expeditions in 13 countries.

The Zootaxa abstract describes Bryconops chernoffi as differing from all its congeners “by the presence of an elongated dark patch of pigmentation immediately after the posterodorsal margin of the opercle, running vertically from the supracleithrum to the distal margin of the cleithrum (vs. absence of a similar blotch), and by a dark dorsal fin with a narrow hyaline band at middle portion of dorsal-fin rays (vs. dorsal fin hyaline or with few scattered chromatophores). It differs further from all its congeners, except B. colanegra, by the presence of a blurred black stripe at the anal fin.”

“It doesn’t really resemble my friend Barry, who in addition to being a fish scientist and environmentalist is also a guitar player and songwriter,” wrote Wesleyan President Michael Roth in a recent blog post. “And now he has fish named in his honor. A true species of Wesleyan.”

Chernoff is the third Wesleyan faculty, in recent years, to have a species named in his or her honor.

In 2010, a dinosaur from the Cretaceous Period (about 110 million years ago) was named Brontomerus mcintoshi for John S. “Jack” McIntosh, Foss Professor of Physics, Emeritus. The fossil, discovered in Utah, is marked by its large, powerful thighs, which may have been used to kick predators and travel over rough terrain. The American-British team of scientists who discovered the remains named the dinosaur for McIntosh, “a lifelong avocational paleontologist.”

Two species of benthic foraminifera are named after Ellen Thomas, the Harold T. Stearns Professor of Integrative Sciences, research professor, earth and environmental sciences; the Smith Curator of Paleontology of the Joe Webb Peoples Museum of Natural History.

Globocassidulina thomasae, discovered in the northeastern Indian Ocean, was named in 1999, and Ossaggittia thomasae, discovered in the eastern Indian Ocean, was named in 2012. They were named in honor of Ellen Thomas, “a well-known specialist on deep-sea benthic foraminifera, who was one of the first micropaleontologists to document the disappearance of Stilostomellidae and Pleurostomellidae in the Pleistocene of the North Atlantic Ocean.”

Students, Faculty, Alumni Present Research at 50th Annual Planetary Science Conference

Jeremy Brossier presented a talk titled "Radiophysical Behaviors of Venus’ Plateaus and Volcanic Rises: Updated Assessment." He also presented a poster titled "Complex Radar Emissivity Variations at Some Large Venusian Volcanoes."

At left, earth and environmental sciences postdoctoral research associate Jeremy Brossier presented a poster titled “Complex Radar Emissivity Variations at Some Large Venusian Volcanoes” during the Lunar and Planetary Science Conference in Texas.

Several Wesleyan students, faculty, and alumni attended the 50th Lunar and Planetary Science Conference (LPSC) March 18-22 in The Woodlands, Texas. Members of the Wesleyan Planetary Sciences Group presented their research on a range of planetary bodies.

This annual conference brings together international specialists in petrology, geochemistry, geophysics, geology, and astronomy to present the latest results of research in planetary science.

Earth and environmental studies major Emmy Hughes ’20 presented a poster titled “Observations of Transverse Aeolian Ridges in Digital Terrain Models” during a session on “Planetary Aeolian Processes.”

Earth and environmental science graduate student Reid Perkins MA ’19 presented a talk titled “A Reassessment of Venus’ Tessera Crater Population and Implications for Tessera Deformation” and a poster titled “Volumes and Potential Origins of Crater Dark Floor Deposits on Venus.”

O’Connell’s Article Published by the Geological Society of America

The article is accompanied by graphic, featured on the cover, of the International Ocean Discovery Program (IODP) ships (left to right): the Chikyu, a riser-equipped platform coring in the western Pacific; the JOIDES Resolution, which recovers cores throughout the ocean; and a Mission Specific Platform (MSP) drilling vessel. Dotted lines—representative depth.

O’Connell’s article is accompanied by a graphic featuring the International Ocean Discovery Program (IODP) ships (left to right): the Chikyu, a riser-equipped platform coring in the western Pacific; the JOIDES Resolution, which recovers cores throughout the ocean; and a Mission Specific Platform (MSP) drilling vessel. The dotted lines show representative depth.

Suzanne O’Connell, professor of earth and environmental sciences, is the author of a cover article titled “Holes in the Bottom of the Sea: History, Revolutions, and Future Opportunities,” published by the Geological Society of America (GSA) Today in January 2019.

Scientific ocean drilling (SOD) contributions include geophysical surveys, core samples, borehole well logs, and sub-seafloor observatories. After more than half a century, involving thousands of scientists from around the world, SOD has been instrumental in developing three geoscience revolutions: (1) plate tectonics, (2) paleoceanography, and (3) the deep marine biosphere.

In this paper, O’Connell explains that without SOD, it is unlikely that our current understanding of Earth processes could have developed. SOD has also been a leader in international collaborations and the open sharing of samples, data, and information. Almost 2.5 million samples have been taken from over 360 km of core located in three repositories. Today about half the members of scientific teams, including co-chief scientists, are women. This program is needed in the future for geoscientists to continue exploring our planet to understand how it functions and to create predictive models, she explains.

At Wesleyan, Professor O’Connell teaches geosciences with a strong emphasis on hands-on research with undergraduates. Her current research focuses on Antarctic climate change using sediment cores from the Weddell Sea, Ocean Drilling Program (ODP) Leg 113. She has authored or coauthored more than 60 refereed publications. Read more about O’Connell’s recent Weddell Sea core research in this College of the Environment blog post.

She is a member of the American Geophysical Union, American Association for the Advancement of Science, Association for Women Geoscientists, the Union of Concerned Scientists and a Fellow of the Geological Society of America. She is also on the governing council of the Geological Society of America and a recipient of the Association for Women Geoscientists Outstanding Educator Award, Wesleyan’s Edgar Beckham Helping Hand Award, and the McConaughy Writing Award.

“Terrible Beast” Takes Residence in Exley Science Center

Exley Science Center is now home to its second prehistoric specimen—a massive land animal known as a Deinotherium giganteum. This elephant-lookalike would have weighed up to 20,000 pounds and would use their massive tusks for stripping bark from tree trunks for eating and for dominating fellow males during mating season.

Exley Science Center is home to its second prehistoric specimen—a massive land animal known as a Deinotherium giganteum—or “terrible beast.” The skull cast is displayed in the hallway between Exley Science Center and the passway to Shanklin Laboratory and is part of the Joe Webb Peoples Museum of Natural History. The exhibit was installed on Feb. 26.

In 2017, the Deinotherium skull was discovered in two wooden boxes by faculty and students exploring Exley Science Center’s seventh-floor penthouse. The skull was once a centerpiece to Wesleyan’s Natural History Museum, located on the top floor of Judd Hall (pictured at left). After the museum closed in 1957, the Deinotherium and thousands of other specimens and objects were relocated and displaced around campus. The skull was first housed in the tunnels beneath the Foss Hill residence hall and relocated to Exley in 1970. (Historic photo courtesy of Wesleyan’s Special Collections and Archives)

Gilmore Speaks on Venus’s Terrain at American Museum of Natural History

Sporting their Earth and Environmental Sciences–labeled jackets, John Hossain MA ’18 and Avi Stein ’17 posed for a photo with Professor Marty Gilmore during her recent talk at the American Museum of Natural History in New York City.

Martha “Marty” Gilmore, the George I. Seney Professor of Geology and professor of earth and environmental sciences, presented a talk at the American Museum of Natural History on Feb. 4 titled “Venus: One Fate of a Habitable Planet.” Gilmore’s presentation was part of the museum’s Frontiers Lecture Series, which highlights the latest advances in our knowledge of the universe by presenting the work of scientists at the cutting edge of astrophysics.

Gilmore, a planetary geologist, uses surface mapping and orbital spectroscopy to study Venus’s terrain. During her talk, she spoke about the planet’s oldest rocks and what they can tell us about the history of water on one of Earth’s closest neighbors.

“Venus is likely to have had an ocean longer than Mars which forces us to consider it as another potentially habitable planet in our solar system,” Gilmore said. “Because it is Earth-sized, it uniquely informs us about the origin and fate of our planet and Earth-sized planets in other solar systems.”

Gilmore supports her investigations by studying minerals formed and/or weathered under conditions on Venus.

Wesleyan alumni Avi Stein ’17 and John Hossain MA ’18 attended the standing-room-only talk.

Gilmore is a Fellow of the Geological Society of America. At Wesleyan, she’s also the director, graduate studies, and co-coordinator, planetary science.

5 Students Receive NASA Connecticut Space Grant Consortium Fellowships, Awards

Two graduate students and three undergraduate students are recipients of Fall 2018 NASA Connecticut Space Grant Consortium (CTSGC) awards. They are among 39 students from 13 CTSGC academic affiliate institutions to be honored.

NASA CTSGC is a federally mandated grant, internship, and scholarship program that is funded as a part of NASA Education. There are Space Grant Consortia in all 50 states, plus Washington, D.C., and Puerto Rico.

Earth and environmental science graduate student Christina Cauley received an $8,000 Graduate Research Fellowship for her project “Chemistry and Biology of Giant Hydrothermal Mounds in Paulina Lake, Oregon.” Her advisor is Joop Varekamp, the Harold T. Stearns Professor of Earth Science and Smith Curator of Mineralogy and Petrology of the Joe Webb Peoples Museum of Natural History. Varekamp also is professor of earth and environmental sciences; professor, environmental studies; and professor, Latin American studies.

Astronomy major Hunter Vannier ’20 received a $5,000 Undergraduate Research Fellowship for his project titled “Using Hubble to Look Back at the Sun’s Historical Trajectory Through the Local Interstellar Medium.” Vannier’s advisor is Seth Redfield, chair and associate professor of astronomy. Redfield also is associate professor, integrative sciences, and co-coordinator, planetary science.

Three other students received $1,000 Student Travel Grants, which covered travel expenses to attend the American Astronomical Society Meeting in Seattle, Wash., in January.

At the meeting, Astronomy major Michael Henderson ’19 presented his senior thesis research titled “High Precision Photometry of Faint White Dwarf Stars from K2 Data.” Henderson’s advisor is Seth Redfield.

Astronomy graduate student Ismael Mireles, presented his master’s thesis research on “Searching for planets around the brightest stars in K2.” Mireles’s advisor is Seth Redfield.

And astronomy graduate student Anthony Santini ’18 presented his BA/MA thesis research titled “Determining Fundamental Properties of Galaxies with X-ray Binary Correlations.” Santini’s advisor is Roy Kilgard, associate professor of the practice in astronomy and associate professor of the practice, integrative sciences.