Tag Archive for Earth and Environmental Sciences

Studies by Varekamp, Thomas Published in Paleoceanography

varekamp

Joop Varekamp

Ellen Thomas

Ellen Thomas

Wesleyan faculty Joop Varekamp and Ellen Thomas are among the authors of a paper on rates of sea-level rise along the eastern U.S. seaboard titled “Late Holocene sea level variability and Atlantic Meridional Overturning Circulation,” published in the journal Paleoceanography, Volume 29, Issue 8, pages 765–777 in August 2014. Varekamp is the Harold T. Stearns Professor of Earth Science, professor of earth and environmental sciences and professor of environmental studies. Thomas is research professor of earth and environmental sciences at Wesleyan, and also a senior research scientist in geology and geophysics at Yale University.

Ellen Thomas discovered that microfossils, such as this  foraminifera fossil, reveal that warm oceans had less oxygen.

Ellen Thomas discovered that microfossils, such as this foraminifera fossil, reveal that warm oceans had less oxygen.

Pre-20th century sea level variability remains poorly understood due to limits of tide gauge records, low temporal resolution of tidal marsh records, and regional anomalies caused by dynamic ocean processes, notably multidecadal changes in Atlantic Meridional Overturning Circulation (AMOC). In the study, Varekamp and Thomas examined sea level and circulation variability along the eastern United States over the last 2,000 years, using a sea level curve constructed from proxy sea surface temperature records from Chesapeake Bay, and 20th century sea level-sea surface temperature relations derived from tide gauges and instrumental sea surface temperatures.

Thomas also is a co-author of a paper titled ‘I/Ca evidence for upper ocean deoxygenation during the PETM‘ published in the Paleoceanography, October 2014.

In this paper, Thomas suggests that the Paleocene-Eocene Thermal Maximum (PETM), a potential analog for present and future global warming, may help in such forecasting future deoxygenation and its effects on oceanic biota. Forecasting the geographical and bathymetric extent,

Royer’s Study Suggests that the Meteorite That Wiped Out Dinosaurs Changed Forests

Dana Royer, associate professor of earth and environmental sciences.

Dana Royer, associate professor of earth and environmental sciences, is the co-author of a study that suggests fast-growing deciduous plants replaced slower-growing evergreen plants after an impact of a meteorite 60 million years ago. (Photo by Olivia Drake)

Sixty-six million years ago, a meteorite struck the Earth with enough force that the ensuing environmental changes, including floods, earthquakes, variable temperatures and light-obscuring dust clouds, possibly wiped out dinosaurs and other pre-historic life. Scientists believe this opened a path for mammals, and ultimately humans, to evolve.

A new study by Dana Royer, associate professor of earth and environmental sciences, and colleagues from the University of Arizona and the Denver Museum of Nature and Science suggests that the chaos in the wake of the space rock’s impact changed the Earth’s plant life as well. Deciduous plants survived and flourished to a much greater extent than flowering evergreens, the scientists believe, probably because their properties made them much better able to respond to climate conditions post-impact. The deciduous plants, not needing to maintain their leaves year round, essentially needed less energy for survival.

Royer’s Study Published in PLOS Biology

Dana Royer

Dana Royer

Dana Royer, associate professor of earth and environmental sciences, is the co-author of “Plant Ecological Strategies Shift Across the Cretaceous-Paleogene Boundary,” published in PLOS Biology on Sept. 15.

The study reveals that a meteorite that hit Earth 60 million years ago – and may have led to the mass extinction of the world’s dinosaur population – also led to a shift in the landscape of plants, particularly deciduous plants.

Royer and his colleagues showed how they applied bio-mechanical formulas to fossilized leaves of flowering plants dating from the last 1.4 million years of the Cretaceous period and the first 800,000 of the Paleogene. Read more about Royer’s study in this News @ Wesleyan article.

Resor Delivering 6 Lectures to Petroleum Geoscientists in Australia

Associate Professor Phil Resor is delivering six lectures in Australia this June.

Associate Professor Phil Resor is delivering six lectures in Australia this June. He is the 2014 AAPG Distinguished Lecturer.

Philip Resor, associate professor of earth and environmental sciences, is taking his knowledge of petroleum down under.

Between June 18-26, Resor, a Distinguished Lecturer for the American Association of Petroleum Geologists (AAPG), is delivering six lectures in Australia. The talks are geared toward members of the Petroleum Exploration Society of Australia (PESA) and a general petroleum industry audience.

Phil Resor at a talk in Melbourne.

Phil Resor at a talk in Melbourne.

While abroad, Resor will speak on “Syndepositional Faulting of Carbonate Platforms” and “Revisiting the Origin of Reverse Drag.”

He’ll be lecturing in Melbourne, Adelaide, Perth, Brisbane, Sydney and Canberra.

A specialist in structural geology, Resor’s work integrates field mapping, remote sensing, and numerical modeling to better understand the mechanics of faulting. Recent projects have focused on the causes of syndepositional faulting in carbonate platforms, deformation around normal faults, folding on Venus, and the effects of fault zone geometry on earthquake slip.

Prior to joining the faculty at Wesleyan, Resor worked for several years as an exploration geologist in the oil and gas industry.

sydney

Phil Resor in Sydney.

Singer ’15 to Study Moon Rocks as Connecticut Space Grant Fellow

Jack Singer '15 holds a fragmented lunar sample (Apollo 12039,3), a crucial sample for studying his mineral of interest — apatite — on the moon.

Jack Singer ’15 holds a fragmented lunar sample (Apollo 12039,3), a crucial sample for studying his mineral of interest — apatite — on the moon. This summer, Singer received a Connecticut Space Grant College Consortium grant to fund his summer research in the Earth and Environmental Sciences Department.

As a recent recipient of an undergraduate research fellowship, Jack Singer ’15 is spending his summer at Wesleyan studying the geochemical evolution of the moon. 

The fellowship, supported by the Connecticut Space Grant College Consortium, comes with a $5,000 award. Grantees are expected to work on research related to space/aerospace science or engineering under the guidance of a faculty member or a mentor from industry.

By using a microscope in Wesleyan's Solar Systems Geochemistry Lab, Jack Singer takes a closer look at a Lunar sample.

By using a microscope in Wesleyan’s Solar Systems Geochemistry Lab, Jack Singer takes a closer look at a lunar sample.

For the next three months, Singer will work on various research projects with his advisor James Greenwood, assistant professor of earth and environmental science. Singer will first prepare a fragmented lunar sample (Apollo 12035,76) for analysis under an ion microprobe. An ion microprobe applies a beam of charged ions to the sample and helps determine the composition of the material.

This rock contains olivine, a mineral that is mysteriously sparse in many different lunar samples.

“By analyzing the melt inclusions contained within olivine in this rock, I’ll be able to better understand geochemical evolution of the moon,” Singer said.

Singer’s second project is more experimental. He’s attempting to model and quantify diffusion in a late-stage lunar environment (one of the last regions to cool on the moon) by synthesizing a granite-rich model lunar glass.

Singer will heat this glass past its melting point and place it in contact with solid terrestrial apatite — the Moon’s major water-bearing mineral — and measure how elements diffuse across the glass-grain (or solid-liquid) boundary.

Jack Singer and his advisor, James Greenwood, will travel to Japan this summer to use an ion microprobe at Hokkaido University.

Jack Singer and his advisor, James Greenwood, will travel to Japan this summer to use an ion microprobe at Hokkaido University.

“This type of analysis helps us to better understand the processes that occurred during the last stages of lunar cooling,” he explained.

In addition, Singer and Greenwood will travel to Japan this summer to use an ion microprobe at Hokkaido University.

“This machine allows us to analyze and measure stable isotope ratios in the minerals we are interested in, and can therefore tell us something about the fractionation and geochemical history of the lunar body,” Singer said.

Next fall, Singer will write about his research findings.

Thomas’s Paper Published in Paleoceanography

The deep-sea benthic foram Aragonia velascoensis went extinct about 56 million years ago as the oceans rapidly acidified. (Photo by Ellen Thomas)

The deep-sea benthic foram Aragonia velascoensis went extinct about 56 million years ago as the oceans rapidly acidified. (Photo by Ellen Thomas)

Ellen Thomas, research professor of earth and environmental sciences, is the author of a paper titled “Rapid and sustained surface ocean acidification during the Paleocene-Eocene Thermal Maximum,” published in Paleoceanography, May 2014. 

In this paper Thomas and her colleagues document that ocean acidification of the surface ocean not only occurred during past times of global warming and high CO2 levels, but also by how much — about 0.3 pH units. The group studied planktic foraminifers from a drill site in the North Pacific.

Thomas’ study has been highlighted in a press release from Columbia University and also on Phys.org.

NASA Supports Greenwood’s Research on the Moon’s Water

James “Jim” Greenwood

James “Jim” Greenwood

Assistant Professor of Earth and Environmental Sciences James “Jim” Greenwood has received a $331,000 grant from NASA to support his research on the moon’s water.

His proposed research, tracking water in rock samples brought back by the Apollo missions, will “take a giant leap towards solving one of the most important questions in planetary science – whether the Moon is wet or dry,” Greenwood said.

“We’ll be studying pockets of glass trapped in early and late-crystallizing minerals in lunar mare basalt samples,” Greenwood said. “We will measure water and other volatile elements in these trapped melt pockets to reconstruct the volatile history of the samples as they cooled and crystallized near the lunar surface.”

The NASA grant is part of NASA’s Lunar Advanced Science and Exploration Research program.

Greenwood intends to use the grant, which will be distributed over four fiscal years, to fund one Wesleyan undergraduate per summer to conduct research in his lab. The grant will also allow Greenwood to do critical measurement work at Hokkaido University in Sapporo, Japan.

This project is only the latest initiative in Greenwood’s intensive work on lunar rocks, and the Moon’s relative wetness. Most recently he and four colleagues co-authored a paper in the prestigious journal Science, casting doubt on the theory of abundant lunar water, while simultaneously boosting theories around the Moon’s creation, several billion years ago.

 

Thomas’s Paper Published in Nature Geoscience

Ellen Thomas

Ellen Thomas

Ellen Thomas, research professor of earth and environmental sciences, is the co-author of a paper titled “Carbon Sequestration during the Palaeocene–Eocene Thermal Maximum by an Efficient Biological Pump,” published in the April 2014 edition of Nature Geoscience.

In the paper, Thomas explains how ocean-dwelling bacteria may have vacuumed up carbon and halted a period of extreme warmth some 56 million years ago. The finding suggests how Earth might once have rapidly reversed a runaway greenhouse effect.

Its effect on global oceanic productivity is controversial. In the paper, Thomas and her colleagues present records of marine barite accumulation rates that show distinct peaks during this time interval, suggesting a general increase in export productivity. The authors propose that changes in marine ecosystems, resulting from high atmospheric partial pressure of CO2 and ocean acidification, led to enhanced carbon export from the photic zone to depth, thereby increasing the efficiency of the biological pump. Higher seawater temperatures at that time increased bacterial activity and organic matter regeneration.

Gabriel Popkin ’03 wrote about Thomas’s research in a April 2014 article titled “Ocean Bacteria May Have Shut Off Ancient Global Warming” in Science News.

Greenwood, Colleagues Debunk Sloshy Lunar Theory

James Greenwood, assistant professor of earth and environmental sciences, studies the potential of water on the moon.

James Greenwood, assistant professor of earth and environmental sciences, studies the potential of water on the moon.

James “Jim” Greenwood, assistant professor of earth and environmental sciences, and four colleagues have published a paper that casts doubt on the theory of abundant water on the moon while simultaneously boosting theories around the creation of the moon, several billion years ago.

The paper, “The Lunar Apatite Paradox,” published March 20 in the prestigious journal Science, stems from work involving the mineral apatite, the most abundant phosphate in the solar system. (Along with its presence on planets, it’s found in teeth and bones.)

Initial work on the lunar rocks brought back to Earth by the Apollo missions indicated that the Moon was extremely dry. Any evidence of water was dismissed as contamination from Earth.

But more recent experiments have shown the presence of plenty of water in grains of apatite derived from lunar rocks. Greenwood and colleagues sought to figure out whether, or how that could be.

“We formulated a solution to the problem of how you get this much water into moon apatite by using a mathematical model,” Greenwood said.

Gilmore, Greenwood, Martin ’14, Dottin ’13 Attend Planetary Science Conference

At left, James Dottin '13 and Peter Martin '14 reunited at the Lunar and Planetary Science Conference in March. Both presented papers at the annual conference.

At left, James Dottin ’13 and Peter Martin ’14 reunited at the Lunar and Planetary Science Conference in March. Both presented papers at the annual conference.

Two faculty, one student and one alumnus made paper presentations at the 45th Lunar and Planetary Science Conference in The Woodlands, Tex., March 17-21.

The Planetary Science Conference brings together international specialists in petrology, geochemistry, geophysics, geology and astronomy to present the latest results of research in planetary science. The five-day conference included topical symposia and problem-oriented sessions. During the conference, Marty Gilmore, chair and associate professor of earth and environmental sciences, presented a paper on the “Venus Exploration Roadmap to the Venus Exploration Analysis Group (VEXAG)” on March 20.

James Greenwood, assistant professor of earth and environmental sciences, presented “Hydrogen Isotopes of Water in the Moon: Evidence for the Giant Impact Model from Melt Inclusion and Apatite in Apollo Rock Samples,” on March 19.

Peter Martin '14 presented a poster titled "Modeling and Mineralogical Analyses of Potential Martian Chloride Brines."

Peter Martin ’14 presented a poster titled “Modeling and Mineralogical Analyses of Potential Martian Chloride Brines.”

Peter Martin ’14 presented his research on “Modeling and Mineralogical Analyses of Potential Martian Chloride Brines” on March 20.  Martin’s travel to the conference was funded by a Connecticut Space Grant and a USRA Thomas R. McGetchin Memorial Scholarship Award. Gilmore is Martin’s advisor.

James Dottin ’13, who is currently a Ph.D. student in geology at the University of Maryland,  spoke on “Isotope Evidence for Links between Sulfate Assimilation and Oxidation of Martian melts from Meteorites MIL 03346, MIL 090030, MIL 090032 and MIL 090136″ on March 21.  While at Wesleyan, Dottin participated in the McNair Program. Greenwood was Dotton’s advisor.

Gilmore also presented a paper on “Are Martian Carbonates Hiding in Plain Sight? VNIR Spectra of Hydrous Carbonates,” which was co-authored by Patrick Harner MA ’13. Harner is a Ph.D. student at the Lunar and Planetary Laboratory at the University of Arizona. Harner completed this research while a student at Wesleyan.

Greenwood’s Study Published in Science

James “Jim” Greenwood, assistant professor of earth and environmental sciences, and four colleagues have co-authored a paper titled “The Lunar Apatite Paradox,” published in the  journal Science on March 20. 

The study casts doubt on the theory of abundant water on the moon while simultaneously boosting theories around the creation of the moon, several billion years ago.

Porter ’15 Works as Diversity Intern with Ocean Drilling Program

Nishaila Porter ’15 and her fellow Diversity Intern, Ernesto Martinez from the University of California, Berkeley, were included in "Core Discoveries: The Newsletter for US Scientific Ocean Drilling.

Nishaila Porter ’15 and her fellow Diversity Intern, Ernesto Martinez from the University of California, Berkeley, were included in “Core Discoveries: The Newsletter for US Scientific Ocean Drilling.”

Over the summer, Nishaila Porter ’15 worked on a research project as a 2013 Diversity Intern at Columbia University. The Integrated Ocean Drilling Program and the U.S. Implementing Organization cosponsored the Lamont Doherty Earth Observatory Summer Intern Program at Columbia University for the second consecutive year.

The goal of the Columbia University Diversity Internship is to “expose minority students to careers in scientific ocean drilling by providing them with a 10–12 week educational and career building experience.” Current interns work with mentors on research projects using scientific ocean drilling data.

While working on the project, titled “Which Marine Fossil Assemblages Best Match Ice Core Assemblages,” Porter used samples from sites with sediments of Eocene age that are rich in diatom and compared them to the diatom assemblage in the GISP2 ice core that was collected in Greenland in order to determine the likely source of diatoms in the ice core.

Porter’s advisor is Suzanne O’Connell, professor of earth and environmental sciences.