Lake bed reveals details about ancient Earth

Rice University researcher helped find oxygen evidence of atmospheric production

by Mike Williams

HOUSTON – (July 18, 2018) – Sleuthing by a Rice University postdoctoral fellow is part of a new Nature paper that gives credence to theories about Earth’s atmosphere 1.4 billion years ago.

Rice’s Justin Hayles and his colleagues, led by Peter Crockford at McGill University in Montreal, analyzed samples from an ancient Canadian lake bed that turned up anomalous oxygen isotopes embedded in deposits of sulfate. The oxygen provides hints at the extent of life on ancient Earth’s surface.

Postdoctoral fellow Justin Hayles

The researchers found the planet’s gross primary production – a measure of processes like photosynthesis – was a small fraction of modern levels during a stretch of the Proterozoic eon known to researchers as the “Boring Billion” because of the planet’s environmental and evolutionary stability.

“The Boring Billion is called boring because it seemed for a long time that nothing remarkable was occurring on Earth’s surface, but the evolution of Earth and the life on its surface continued,” Hayles said.

Hayles, a National Science Foundation postdoctoral fellow, did the work as a Ph.D. student at Louisiana State University. He joined the Rice lab of Laurence Yeung, an assistant professor of Earth, environmental and planetary sciences, two years ago.

Hayles’ analysis with specialized mass-spectrometry equipment was part of the effort to analyze cores taken from the lake bed. “When the project started, we were just looking to see what sulfates looked like through Earth’s history,” he said. “In the process, we analyzed this one set of samples and found an anomaly.”

That anomaly was an unexpected amount of oxygen-17, one of three stable isotopes of oxygen. “This was shocking because we thought this anomaly could only exist when atmospheric carbon dioxide concentrations are extremely high, such as during a ‘snowball Earth‘ event,” Hayles said. “It turns out that this condition is not needed if concentrations of atmospheric oxygen (O2) and bioproductivity are much lower than today.”

Because oxygen is highly reactive, it easily combined with sulfide in what was then a lake at Ontario’s Sibley Basin. “When you form sulfate from sulfide, you get a little bit of O2 incorporated,” he said. “That is preserved as a capsule of the ancient atmosphere, so it contains oxygen from back in the Proterozoic, 1.4 billion years ago.”

The researchers suggested their discovery is the oldest direct measurement of atmospheric oxygen isotopes by nearly a billion years, taken from a time when microorganisms, including bacteria and algae, were beginning to ramp up production through photosynthesis but had not yet reached the fertile period that triggered a second “oxygenation event.”

“It has been suggested for many decades now that the composition of the atmosphere has significantly varied through time,” said Crockford, now a postdoctoral fellow at Princeton. “We provide unambiguous evidence that it was indeed much different 1.4 billion years ago.”

The researchers said their discovery could help in the search for clues to life on other planets.

“Earth during the Proterozoic was like an alien world compared with the modern Earth,” Hayles said. “The atmosphere had only a small amount of oxygen and the environment was arguably much warmer.

“Knowing how well microbial life thrived tells us what to expect on a hypothetical planet with a similar environment,” he said. “There is potential that if Mars was ever sufficiently Earth-like and the right material found its way to Earth, this technique could provide similar evidence.”

Scientists at McGill University, Louisiana State University, Lakehead University, the Weizmann Institute of Science in Israel, Peking University, Yale University, Princeton University and the University of California, Riverside took part in the study.

The research was supported by the Natural Sciences and Engineering Research Council of Canada, the Fonds de Recherche du Quebec-Nature et Technologies and the University of Colorado Boulder.

Read the abstract at http://dx.doi.org/10.1038/s41586-018-0349-y

Joyeeta Bhattacharya selected for Urbino Summer School in Paleoclimatology

Ph.D. candidate Joyeeta Bhattacharya is one of ten U.S. participants- among 60 world-wide- selected to participate in the coveted Urbino Summer School in Paleoclimatology (USSP).  The NSF sponsored fellowship is a three week long intensive course and workshop that provide participants with an advanced working knowledge on paleobiological and geochemical proxy data and how they are used in the reconstruction and modeling of past climates.

This 15th class of the USSP consortium, taking place July 11-27, 2018, will focus on past climate dynamics, with special emphasis on the analysis of the long-term carbon cycling and its implications in the understanding of present and future climates. The integrated lectures, symposia, field excursions, and exercises include biogeochemical cycling, paleoceanography, continental systems, and all aspects of deep-time climate modeling. Techniques, systems and models will be explored through interactive discussions of Cretaceous OAEs, P/E hyperthermals, the “Greenhouse to Icehouse” transition, and Neogene and Quaternary climate dynamics.

Ph.D. candidate Joyeeta Bhattacharya holding a section of carbonate sediment core aboard the JOIDES Resolution, IODP Expedition 371. Image courtesy of J. Bhattacharya and IODP.

The summer school is taught by the world’s leading senior scientists, with student selections based on the strength of their CVs and recommendations.  “Since my Ph.D. is quite related to Paleoclimatology and Paleoceanography as well as Sedimentology, attending Urbino is going to bolster my research skills, my knowledge and my ability as a researcher in this domain,” said Bhattacharya.

Bhattacharya applied and was accepted last summer, but could not attend because the dates conflicted with her participation on the Integrated Ocean Discovery Program (IODP) Expedition 371 cruise.  “[This year] I was accepted with full expenses covered by NSF.  My participation on shipboard courses with Texas A&M University,  and my participation as a Shipboard Scientist on IODP Expedition 371 were the key determining factors for me getting accepted.”

 

 

“Joyeeta’s participation at USSP continues an admirable Rice “tradition” of placing our graduate students in prestigious international “schools”. For USSP, Joyeeta follows fellowships granted to Lizette Leon-Rodriguez (Ph.D., 2011) and Benjamin Slotnick (Ph.D., 2015)”, said Gerald Dickens, EEPS professor and advisor to Bhattacharya.

-L. Welzenbach

Europium points to new suspect in continental mystery

Europium points to new suspect in continental mystery Study: Rare earth element implicates garnet for continents’ missing iron HOUSTON — (May 16, 2018) — Clues from some unusual Arizona rocks pointed Rice University scientists toward a discovery — a subtle chemical signature in rocks the world over — that could answer a long-standing mystery: What […]

Rice, UH team preps for massive Antarctic glacier study

A team of scientists from Rice University, the University of Houston, the University of Alabama and Lamont-Doherty Earth Observatory will participate in an ambitious $25 million study aimed at determining how quickly Antarctica’s massive Thwaites Glacier could collapse.

Thwaites Glacier (Photo by James Yungel/NASA)

The Thwaites research program, a joint undertaking of the National Science Foundation and the United Kingdom’s Natural Environment Research Council, was announced today. U.S. and U.K. officials say the International Thwaites Glacier Collaboration (ITGC) is the largest joint project undertaken by their nations in Antarctica since the mapping of the Antarctic Peninsula more than 70 years ago.

Antarctica is covered by ice up to 2 miles thick, and gravity compresses the ice and causes it to move under its own weight. Thwaites drains ice from an area of West Antarctica almost as large as the state of Washington and is one of the largest Antarctic contributors to modern sea-level rise. From satellite measurements, scientists know that Thwaites’ rate of ice loss has doubled since the 1990s. A full collapse of the glacier could add several inches to global sea levels, and ITCG includes eight projects that hope to answer key questions about how much and how quickly Thwaites is changing.

Lauren Simkins (Photo by Jeff Fitlow/Rice University)

The Thwaites Offshore Research (THOR) project is led by principal investigator Julia Wellner, assistant professor of Earth and atmospheric sciences at UH, and includes Rice co-investigators Lauren Simkins and John Anderson, both of the Department of Earth, Environmental and Planetary Sciences. Simkins is a postdoctoral research associate and Anderson is the Maurice Ewing Chair in Oceanography.

“We have an important role in understanding changes in Thwaites Glacier,” Simkins said. “The offshore geological record contains signatures of the glacier’s retreat, and a better understanding of how the glacier has behaved in the past will allow us to better interpret what is observed today and what is predicted for the future.”

Because the land beneath Thwaites is below sea level, the glacier’s “grounding line” — the place where ice, land and water meet — is beneath a thick ice shelf that extends miles into the Amundsen Sea. Inflows of warming ocean currents beneath this and other Antarctic ice shelves have caused the grounding lines of Thwaites and other West Antarctic glaciers to retreat rapidly in recent years. THOR will use a suite of marine geological and geophysical data to examine how Thwaites retreated in the past and to determine key boundary conditions that help control its retreat.

This schematic shows an ice shelf extending miles beyond the “grounding line” where an Antarctic glacier meets both land and sea. Black lines t1, t2 and t3 show where the ice sheet was grounded to the seafloor during pauses in ice retreat. Rice University marine geologists will study the past and present grounding lines of Thwaites glacier as part of a massive U.S.-U.K. research effort. (Image courtesy of L. Prothro/Rice University)

 

THOR scientists will make high-resolution geophysical surveys of the seafloor from research ships and they’ll collect sediments from the sea floor as well as a drilling rig that can melt holes through up to 5,000 feet of the floating ice shelf.

Additional co-investigators on the THOR project include the University of Alabama’s Rebecca Minzoni, Lamont-Doherty Earth Observatory’s Frank Nitsche and U.K.-based investigators Robert Larter, Alastair Graham, Claus-Dieter Hillenbrand, James Smith and Kelly Hogan.

 

Sub-sea rift spills secrets to seismic probe

Rice-led study yields first clues about internal structure of Galicia margin

The first study to spring from a Rice University-led 2013 international expedition (click to read the 2013 press release Ocean explorers want to get to the bottom of Galiciato map the sea floor off the coast of Spain has revealed details about the evolution of the fault that separates the continental and oceanic plates.

A Rice University-led seismic survey of the Galicia margin off the coast of Spain has produced new details about the passive rift that separates the oceanic and continental plates, and in particular the S-reflector, a prominent detachment fault within the transition zone. (Credit: Nur Schuba/Rice University)

A paper in Earth and Planetary Science Letters by Rice graduate student Nur Schuba describes the internal structure of a large three-dimensional section of the Galicia, a non-volcanic passive margin between Europe and the Atlantic basin that shows no signs of past volcanic activity and where the crust is remarkably thin.

That thinness made it easier to capture 3-D data for about 525 square miles of the Galicia, the first transition zone in the world so analyzed.

Sophisticated seismic reflection tools towed behind a ship and on the ocean floor enabled the researchers to model the Galicia. Though the rift is buried under several hundreds of meters of powdered rock and invisible to optical instruments, seismic tools fire sound into the formation. The sounds that bounce back tell researchers what kind of rock lies underneath and how it’s configured.

Among the data are the first seismic images of what geologists call the S-reflector, a prominent detachment faultwithin the continent-ocean transition zone. They believe this fault accommodated slipping along the zone in a way that helped keep the crust thin.

“The S-reflector, which has been studied since the ’70s, is a very low-angle, normal fault, which means the slip happens due to extension,” Schuba said. “What’s interesting is that because it’s at a low angle, it shouldn’t be able to slip. But it did.

“One mechanism people have postulated is called the rolling hinge,” she said. “The assumption is that an initially steep fault slipped over millions of years. Because the continental crust there is so thin, the material underneath it is hot and domed up in the middle. The initially steep fault started rolling and became almost horizontal.

“So with the help of the doming of the material coming from below and also the continuous slip, that’s how it is likely to have happened,” Schuba said.

The Galicia group — from left, Rice graduate student Nur Schuba, alumnus Ara Alexanian and graduate research assistant Mari Tesi Sanjurjo — discuss the northwest portion of the 3-D seismic volume at Rice’s Visualization Lab. (Credit: Gary Linkevich/Rice University)

 

The large data set also provided clues about interactions between the detachment fault and the serpentinized mantle, the dome of softer rock that presses upward on the fault and lowers friction during slippage. The researchers believe that led the Galicia to evolve differently, weakening faults and allowing for longer durations of activity.

The research is relevant to geologists who study land as well as sea because detachment faults are common above the water, Schuba said. “One of my advisers, (adjunct faculty member) Gary Gray, is jazzed about this because he says you can see these faults in Death Valley and Northern California, but  you can’t ever see them fully because the faults keep going underground. You can’t see how deep they go or how the fault zones change or how they’re associated with other faults.

“But a 3-D dataset is like having an MRI,” she said. “We can bisect it any way we want. It makes me happy that this was the first paper to come out of the Galicia data and the fact that we can see things no one else could see before.”

Rice University alumnus Brian Jordan, co-author of a new study on the Galicia margin based on an extensive seismic survey led by Rice, points out crustal faults that connect to the margin’s S-reflector. (Credit: Gary Linkevich/Rice University)

Co-authors of the paper are Julia Morgan and Dale Sawyer, both Rice professors of Earth, environmental and planetary sciences; Rice alumnus Brian Jordan, now of BP America; Donna Shillington, the Lamont Associate Research Professor at Columbia University; Tim Reston, a professor of geology at the University of Birmingham, England; and Jonathan Bull, a professor of geology and geophysics at the University of Southampton, England.

The National Science Foundation, the U.K. Natural Environment Research Council and the GEOMAR Helmholtz Center for Ocean Research supported the research.

Rajdeep Dasgupta receives Duncan Award

Charles Duncan Award for Outstanding Academic Achievement

Rajdeep Dasgupta, professor of Earth, environmental and planetary sciences, received the Duncan Award,  which is presented by Rice deans upon the recommendation of senior faculty. It honors tenure-track or tenured faculty members who have less than 10 years of experience.

Francis Albarède wins Nemmers Prize

Francis Albarède, Emeritus Professor at the Ecole Normale Supérieure de Lyon and Wiess visiting professor at Rice in the Department of Earth, Environmental and Planetary Sciences, is the inaugural  Nemmers Prize winner in Earth Sciences by Northwestern University.

Albarède is recognized for his “fundamental applications of geochemistry to earth sciences” to include pioneering the use of unconventional stable isotopes as markers of natural processes and exploring the use of isotopic tracers in applications as diverse as archeology, history, biology and medicine. Image: Francis Albarède.

“I would never have expected such a huge and humbling distinction. I always thought of myself as jack-of-all-trades. It looks like my colleagues actually appreciated my contribution to the development of new instruments, such as Secondary Ion Mass Spectrometers in the ’80s and most notably Multiple Collector Inductively Coupled Plasma Mass Spectrometry in the ’90s, and some long-lasting analytical protocols.”

As a regular visitor to Rice since 2008, Albarède has applied his cutting-edge mathematical models, which bridge the physics and chemistry of natural processes, to better understand the geological processes operating from within the deep earth, to the crust and beyond.  His work with Rice faculty Cin-Ty Lee and Rajdeep Dasgupta has produced work that has shifted conventional knowledge of Earths early mantle chemical behavior, as well as confirmed the status of water and other volatiles in the Moon- all based on analyses produced at Rice.

“Cin-ty’s great intuition that the lack of fractionation between zinc and iron during magma formation and ascent proved to be extremely crucial in assessing the lack of water in the Moon. Against the popular idea that the interior of the Moon may have been wet, we showed that the tenet of Apollo years, a dry Moon, was still valid.”

The Nemmers Prize endowment was created in 1994 at Northwestern University by Erwin and Frederic Nemmers for economics, mathematics, musical composition, medical science, with Earth Sciences recently added in 2016. The award includes a $200,000 cash prize, and the opportunity to spend several weeks in the fall of 2018 at Northwestern to work with students and faculty on a number of scholarly activities.

“I strongly believe that geochemistry, and particularly isotope geochemistry, has the unique power of dealing with complex systems through the laws of physics. It provides a unified vision of seemingly very different processes and objects, from earth and planetary sciences to medicine and archeology using a rather coherent set of concepts and analytical tools. My ambition at Northwestern is to put together a new course demonstrating the unifying power of Geochemistry and its applications to a range of fields and a variety of objects. This course naturally can be used at Rice during my stay in 2019.”

Scientific Publications:

Lee, C. T. A., Luffi, P., Le Roux, V., Dasgupta, R., Albarède, F., and Leeman, W. P. (2010) The redox state of arc mantle using Zn/Fe systematics. Nature 468, 681-685.

Albarede, F., Albalat, E., and Lee, C.-T. A. (2015) An intrinsic volatility scale relevant to the Earth and Moon and the status of water in the Moon. Meteoritics and Planetary Sciences, 50 (4), 568-577.