̽��ֱ�� of Cambridge - Sally Gibson

Scientists zero in on the role of volcanoes in the demise of dinosaurs

cmm201 — Mon, 29 Mar 2021 19:00:00 +0000

Earth has experienced five major extinction events over the last 500 million years, the fifth and most recent responsible for wiping out the dinosaurs 66 million years ago. Massive volcanic eruptions have been identified as a major driver in the environmental change which triggered at least three of these extinctions.

But what dealt the final blow to the dinosaurs – whether an enormous outpouring of lava from the Deccan Traps volcanic province in India or a large asteroid impact or perhaps a combination of the two – has remained open to debate.

Now, a multi-institutional research team, led by scientists from the City ̽��ֱ�� of New York (CUNY), and involving the ̽��ֱ�� of Cambridge, has, for the first time, accurately pinpointed the timing and amount of carbon released from Deccan Traps volcanic province. ̽��ֱ��new data means scientists can now assess the role of volcanism in climate shifts around the End-Cretaceous mass extinction.

̽��ֱ��team’s data show that CO₂ outgassing from Deccan Traps magmas can explain a warming of Earth’s global temperatures by roughly 3 degrees Celsius during the early phases of Deccan volcanism, but shows that the warming had lessened by the time of the mass extinction event.

Their findings support the theory that later Deccan magmas were not releasing that much CO₂, suggesting that volcanic carbon emissions didn’t play a major role in the dinosaur’s extinction.

“ ̽��ֱ��results are important because they show that major volcanic events can release substantial amounts of CO₂ not just from surface vents, but also from the large and complex plumbing systems that feed them. Even though volcanic carbon emissions alone couldn’t have triggered the mass extinction, our data highlights their influence on our planet's climate and habitability,” said co-author Professor Sally Gibson, from Cambridge's Department of Earth Sciences.

̽��ֱ��team had to search through hundreds of Deccan lava samples to identify suitable candidates to profile for their trapped CO₂ content. “In modern volcanic eruptions, such as the current one in Iceland, the CO₂ is trapped in crystals that are embedded in glassy fragments of rapidly cooled magma, but these are fragile and not preserved in the 65 million-year-old Deccan Traps,” said Gibson.

Recent research has identified a global warming event that occurred several hundred thousand years before the End-Cretaceous extinction. Some scientists have linked the eruption of the Deccan Traps to this warming event, but there is debate over whether the lavas that erupted could have released enough CO₂ into the atmosphere to cause it. Adding to this mystery, the lava volumes that erupted during this time are relatively small compared to the volumes erupted during subsequent stages of Deccan Traps activity. A major challenge in this debate has been the lack of CO₂ data on Deccan magmas from this time.

“ ̽��ֱ��new data highlights that carbon outgassing from lava volumes alone couldn’t have caused that level of global warming. But, when we factored in outgassing from magmas that froze beneath the surface rather than erupting, we found that the Deccan Traps could have released enough CO₂ to explain this warming event,” said lead-author Andres Hernandez Nava, a PhD student in ̽��ֱ��Graduate Center, CUNY Earth.

For their study, the team used lasers and beams of ions to measure the amount of CO₂ inside tiny droplets of frozen magma trapped inside Deccan Traps crystals from the End Cretaceous time period. They also measured the amounts of other elements, such as barium and niobium, which are indicators for how much CO₂ the magmas started out with. Finally, they performed modeling of latest Cretaceous climate to test the impacts of Deccan Traps carbon release on surface temperatures.

“Our lack of insight into the carbon released by magmas during some of Earth’s largest volcanic eruptions has been a critical gap for pinning down the role of volcanic activity in shaping Earth’s past climate and extinction events,” said Black, the study’s principal investigator and a professor in the Earth and Environmental Science program at ̽��ֱ��Graduate Center CUNY and City College of New York. “This work brings us closer to understanding the role of magmas in fundamentally shaping our planet’s climate, and specifically helps us test the contributions of volcanism and the asteroid impact in the end-Cretaceous mass extinction.”

Reference:
Hernandez Nava et al. Reconciling early Deccan Traps CO2 outgassing and pre-KPB global climate. PNAS (2021). DOI : 10.1073/pnas.2007797118

Adapted from a press release by ̽��ֱ��Graduate Center, CUNY.

Researchers have uncovered evidence suggesting that volcanic carbon emissions were not a major driver in Earth’s most recent extinction event.

Even though volcanic carbon emissions alone couldn’t have triggered the mass extinction, our data highlights their influence on our planet's climate and habitability

Sally Gibson

Loÿc Vanderkluysen, Drexel ̽��ֱ��

Deccan Traps, India

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Fingerprinting rare earth elements from the air

lw355 — Fri, 01 Jul 2016 09:00:00 +0000

Next time you use your mobile phone, spare a moment for the tiny yet vital ingredients that make this and many other technologies possible – the rare earth elements (REEs).

Used in computers, fibre optic cables, aircraft components and even the anti-counterfeiting system in euro notes, these materials are crucial for an estimated £3 trillion worth of industries, with demand set to increase over the coming decades.

Currently, more than 95% of the global demand for the REEs is met by a single mine in China. ̽��ֱ��security of the future supply of these 17 critical metals, which include neodymium, europium, terbium, dysprosium and yttrium, is a major concern for European governments, and the identification of potential REE resources outside China is seen as a high priority.

Over the past year, Drs Sally Gibson, Teal Riley and David Neave have been working together through a ̽��ֱ�� of Cambridge–BAS Joint Innovation Project (see panel) on a remote sensing technique that could aid the identification of REEs in rocks anywhere in the world. ̽��ֱ��project brings together expertise in remote sensing, geochemistry and mineralogy from both institutes to take advantage of the properties that make the metals so special.

“Despite their name, the rare earth elements are not particularly rare and are as abundant in the Earth’s crust as elements such as copper and tin,” explains Riley from BAS. “However, to be extractable in an economic way, they need to be concentrated into veins or sediments.” It’s the identification of these concentrations that is critical for the future security of supply. REEs all have an atomic structure that causes them to react to photons of light through a series of electronic transitions. This gives them the magnetic and electrical properties for which they are prized in plasma TVs, wind turbines and electric car batteries. And it also means that for every photon of light they absorb, they reflect other photons in a unique way – it is this property that the researchers have latched onto as a means of tracking them down.

“ ̽��ֱ��light they reflect is so specific that it’s like a fingerprint, one that we can capture using sensors that pick up light emissions,” explains Gibson, from Cambridge’s Department of Earth Sciences. “ ̽��ֱ��difficulty, however, is that in naturally occurring rocks and minerals, the rare earth element emission spectra are mixed up with those of other elements. It’s like looking at overlapping fingerprints – the challenge was to work out how to tease these spectral fingerprints apart.”

Gibson has over 20 years’ experience investigating how REEs are generated during the melting of the Earth’s mantle. “Collective understanding of the geological make-up of the world is now good enough that we know where to look for these rocks – at sites of a certain type of past tectonic activity – but even then it’s difficult to find them.”

Riley is the head of the Geological Mapping Group at BAS – his job is to “map the unmapped” areas of the polar region to understand the geological evolution of the continent. Much of his work depends on being able to develop new ways of interrogating satellite- and aircraft-based remote sensing data. “It became a frustration that we could collect data and say generally what was on the ground but that we couldn’t define individual fingerprints, and so we developed the analytical tools to do this.”

Gibson and Neave gathered rocks containing REE-bearing minerals from around the world – sourced from mining companies, museum collections and universities. One such source was the Harker Collection housed in the ̽��ֱ��’s Sedgwick Museum of Earth Sciences. This collection contains specimens of minerals and rocks rich in REEs that were collected decades previously by geologists who were unaware of their economic importance.

Neave analysed the emission spectrum of each rock and related this to its gross and microscopic composition. From this information he began to untangle the individual fingerprints, resulting in what the researchers believe is the most comprehensive ‘spectral database’ of REEs in their natural state – in rocks.

̽��ֱ��next goal is to use this spectral database as a reference source to track down deposits from the air. “Although data from aircraft is now good enough to be analysed in this way, we are waiting for new satellite missions such as the German Environmental Mapping and Analysis Program (EnMAP) to be launched in the next few years,” explains Riley. ̽��ֱ��plan would then be to carry out reconnaissance sweeps of the most likely terrains and explore the possibility of mining these areas. “Our hope is that this research will help to create an internationally unique and competitive capability to map these surprisingly common – yet difficult to find – materials,” adds Gibson.

Vital to many modern technologies yet mined in few places, the ‘rare earth elements’ are in fact not that rare – they are just difficult to find in concentrations that make them economic to mine. Researchers from Cambridge ̽��ֱ�� and the British Antarctic Survey (BAS) are investigating whether the remarkable properties of these materials can be used to track them down from the air.

̽��ֱ��light they reflect is so specific that it’s like a fingerprint, one that we can capture using sensors that pick up light emissions

Sally Gibson

Aurora Cambridge

̽��ֱ��search for rare earth elements is one of a host of ongoing projects between the ̽��ֱ�� and BAS. Like these, a new centre – Aurora Cambridge – will reflect the ethos that innovation developed for the Antarctic is transferable to a global setting.

Aurora Cambridge aims to generate new research and entrepreneurial activity focused on climate change and challenging environments through academic, business and policy partnerships. It will be located at BAS in Cambridge and has been funded by the National Environment Research Council with support from the ̽��ֱ��.

̽��ֱ��building is due to open in 2017; however, 27 ̽��ֱ�� of Cambridge–BAS Joint Innovation Projects are already under way with funding from the Higher Education Funding Council for England – including the development of mapping technologies for rare earth elements led by Drs Sally Gibson and Teal Riley.

Other projects include research on cold-adapted enzymes with potential applications in the biotech industries, remote sensing for conservation of seabirds and marine mammals, and the measurement of coastal vulnerability through sea-level rise. Many involve external industrial partners and other research institutions as well as researchers from BAS and 12 ̽��ֱ�� departments.

“ ̽��ֱ��collaborative projects demonstrate not only the importance of research technology to the Antarctic but also their transferability beyond its shores to a global setting,” explains BAS Director of Innovation Dr Beatrix Schlarb-Ridley. “ ̽��ֱ��SPECTRO-ICE project, for instance, has brought scientists at BAS who are concerned with monitoring the atmosphere above the ice cap together with physicists and mathematicians who are working hard to avoid seeing the atmosphere in their study of the stars – both use similar techniques and need to operate advanced instruments at difficult locations.”

“This is just the beginning,” says BAS Director Professor Jane Francis. “ ̽��ֱ��new innovation centre will help us to extend the range of fruitful partnerships with academia, business, policy makers and the third sector to create tangible benefits for society.”

www.bas.ac.uk/aurora-cambridge

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Did dinosaur-killing asteroid trigger largest lava flows on Earth?

jeh98 — Tue, 12 May 2015 10:15:26 +0000

̽��ֱ��team of researchers, which included Dr Sally Gibson from Cambridge ̽��ֱ��’s Department of Earth Sciences, argue that the impact may have triggered most of the immense eruptions of lava in India known as the Deccan Traps. In a paper published in ̽��ֱ��Geological Society of America Bulletin they claim this would explain the “uncomfortably close” coincidence between the Deccan Traps eruptions and the impact, which has always cast doubt on the theory that the asteroid was the sole cause of the end-Cretaceous mass extinction.

̽��ֱ��Deccan Traps are a vast accumulation of igneous rock, and one of the largest volcanic features on Earth, located on the Deccan Plateau in India. Formed by huge lava flows, they cover an area of approximately 500,000km² and stretch across the Indian subcontinent from Mumbai to Kolkata.

“If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan … the chances of that occurring at random are minuscule,” said team leader Mark Richards, Professor of Earth and Planetary Science at the ̽��ֱ�� of California, Berkeley. “It’s not a very credible coincidence.”

While the Deccan lava flows, which started before the impact but erupted for several hundred thousand years after, probably spewed immense amounts of carbon dioxide and other noxious, climate-modifying gases into the atmosphere, it’s still unclear if this contributed to the demise of most of life on Earth at the end of the Age of Dinosaurs. “This connection between the impact and the Deccan lava flows is a great story and might even be true, but it doesn’t yet take us closer to understanding what actually killed the dinosaurs,” Richards added.

̽��ֱ��disappearance of the landscape-dominating dinosaurs is widely credited with ushering in the age of mammals, eventually including humans.

“Paul Renne’s group at Berkeley showed years ago that the Central Atlantic Magmatic Province is associated with the mass extinction at the Triassic/Jurassic boundary 200 million years ago, and the Siberian Traps are associated with the end-Permian extinction 250 million years ago, and now we also know that a big volcanic eruption in China called the Emeishan Traps is associated with the end-Guadalupian extinction 260 million years ago,” Richards said.

“Then you have the Deccan eruptions – including the largest mapped lava flows on Earth – occurring 66 million years ago coincident with the mass extinction of the dinosaurs. So what really happened?”

Richards teamed up with a multi-disciplinary group of experts to try to discover faults with his idea that the impact off the coast of Mexico triggered the Deccan eruptions, but instead came up with supporting evidence. Paul Renne, a Professor in Residence in the ̽��ֱ�� of California, Berkeley’s Department of Earth and Planetary Science and Director of the Berkeley Geochronology Center, re-dated the asteroid impact and mass extinction two years ago and found them essentially simultaneous. He also found they were within approximately 100,000 years of the largest Deccan eruptions, referred to as the Wai subgroup flows, which produced about 70 percent of the lavas that now stretch across the Indian subcontinent.

Richards and his team found pronounced weathering surfaces marking the onset of the huge Wai subgroup flows, which may indicate a period of inactivity in Deccan volcanism prior to the asteroid impact. Since the team’s manuscript was accepted for publication, new radioisotopic ages published by scientists at Princeton ̽��ֱ�� and preliminary ages from the Berkeley group have confirmed that the Wai lava flows closely postdate the asteroid impact.

“This was an existing massive volcanic system that had been there probably several million years, and the impact gave this thing a shake and it mobilised a huge amount of magma over a short amount of time,” Richards said.

“Based on the distances between erupting volcanoes and the epicentres of earthquakes, a large asteroid impact in Mexico could generate a huge earthquake (equivalent to magnitude 9 or greater) that would have enough seismic energy to shake magma chambers deep in the Earth below the Deccan and cause a sudden massive outpouring of lava, 100,000 years or so after the impact event itself,” explains Gibson.

“Our findings have broad implications for studies of past climate change, evolutionary biology, and how earthquakes might trigger volcanic eruptions.”

Inset image: Cross-sectional diagram to schematically illustrate the Deccan plume melting in the mantle beneath the Indian subcontinent 60 million years ago (from Richards et al., 2015)

Article originally published by the ̽��ֱ�� of California, Berkeley

̽��ֱ��asteroid that slammed into the ocean off Mexico 66 million years ago and killed off the dinosaurs probably rang the Earth like a bell, triggering volcanic eruptions around the globe, according to a multi-disciplinary team of scientists.

If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan … the chances of that occurring at random are minuscule

Mark Richards, ̽��ֱ�� of California Berkeley

SA Gibson

̽��ֱ��Deccan Traps in western India

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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