Two teams of scientists, including three researchers from UC Riverside, report that traces of oxygen appeared in Earth’s atmosphere roughly 100 million years before the “Great Oxidation Event” 2.4 billion years ago. The Great Oxidation Event is when most geoscientists think atmospheric oxygen rose sharply from very low levels and set the stage for animal life that followed almost two billion years later.
Analyzing layers of sedimentary rock in a kilometer-long core sample they retrieved in 2004 from the Hamersley Basin in Western Australia, the researchers found evidence for the presence of a small but significant amount of oxygen 2.5 billion years ago in the oceans and likely also in Earth’s atmosphere.
Because the core was recovered from deep underground, it contains materials untouched by the atmosphere for billions of years. After retrieval, the scientists sliced the core longitudinally for analysis.
Study results appear in a pair of papers in tomorrow’s issue of Science.
The UCR contribution:
Geochemists Timothy Lyons, Steven Bates, and Clinton Scott of the UCR Department of Earth Sciences — working with teams from Arizona State University and the universities of Maryland, Washington, and Alberta — generated elemental and isotopic data that provide indirect, or proxy, evidence for the evolving atmosphere and its relationship to the early evolution of life.
“This is the earliest convincing record for an ephemeral accumulation of oxygen in the biosphere before its irreversible rise beginning 2.4 billion years ago,” said Lyons, a professor of biogeochemistry.
Scott, a graduate student working with Lyons, used metals in the ancient ocean—now trapped in sedimentary rocks—as proxies for the amount of oxygen in the early ocean and atmosphere. His doctoral research provided a baseline for the Australian samples, showing that the 2.5 billion-year old rocks look more like those from younger times when oxygen was higher in the atmosphere.
These results revealed to the UCR geochemists and their colleagues at Arizona State University that oxygen increased significantly but briefly 100 million years before its permanent place in Earth’s atmosphere.
Working principally with colleagues at the University of Maryland, Bates, a research associate, and Lyons analyzed sulfur present in the Australian rocks as another fingerprint of oxygen concentrations at Earth’s surface. Their analysis of the sulfur also confirmed that the world changed briefly but importantly 2.5 billion years ago, presaging the life-affirming oxygenation of the atmosphere 100 million years later.
“We were surprised to see evidence of increasing oxygen in rocks so old,” Lyons said. “And the fact that two independent lines of evidence point in the same direction suggests that Earth’s most dramatic shift in atmospheric composition and its relationship to the evolution of life began earlier and was more complex than most imagined.”
Iqbal Pittalwala | EurekAlert!
Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation
Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences