Bright deposits around a 400km line of explosive volcanic vents
Violent volcanic eruptions on the planet Mercury happened much more recently than previously believed, new research from The Open University reveals.
Published in Geophysical Research Letters this week, the paper concludes that explosive eruptions continued on the planet until a billion years ago, much later than previously thought, showing that Mercury has been volcanically-active through much of its history.
Kuniyoshi, a fresh crater on Mercury < 1 billion years old
Authors of the new research, OU PhD student, Rebecca Thomas and her supervisors Professor David Rothery, Dr Mahesh Anand and Dr Susan Conway used detailed images from NASA’s MESSENGER spacecraft, which has been orbiting the planet since March 2011. They located 150 sites where volcanic vents are surrounded by characteristic deposits of red material exploded out of the vent, more than doubling the number previously known. Among the new examples, they found two where even younger volcanic vents occur inside ‘young’ impact craters.
Rebecca Thomas said:
“Most volcanic activity occurred three to four billion years ago, but the crisp state of preservation of these two impact craters dates them to about a billion years ago.
“This relatively recent volcanism is a really exciting discovery as Mercury, being a much smaller planet than Earth, should have cooled much more since its formation. It’s also a sign that the gases necessary to power these eruptions have been available within the planet for all that time. We used to believe Mercury was depleted in the elements that make up these gases; this evidence means scientists need to rethink these theories.”
Professor of Planetary Geosciences, David Rothery, said:
“You don’t get explosive volcanism without something to drive the explosion, which means magma containing plenty of gas able to expand violently as it approaches the surface. There are several other indications that Mercury is rich in volatile materials.
“This was unexpected of a planet so close to the Sun, and makes Mercury’s origin a mystery that we are keen to solve.”
For a copy of the research paper, entitled ‘Long-lived explosive volcanism on Mercury’, visit http://onlinelibrary.wiley.com/doi/10.1002/2014GL061224/abstract
Notes to editors
About the authors
The paper is Thomas, R. J., D. A. Rothery, S. J. Conway, and M. Anand (2014), Long-lived explosive volcanism on Mercury, Geophysical Research Letters, 41, doi:10.1002/2014GL061224.
Rebecca Thomas is a PhD student supported by a grant from the Science and Technology Facilities Council.
David Rothery heads the European Space Agency’s Mercury Surface & Composition Working Group and is the Lead Scientist on the only UK instrument for Europe’s BepiColombo mission to Mercury, due to be launched in 2016, and is supported by the UK Space Agency and the Science and Technology Facilities Council. He is Professor of Planetary Geosciences at the Open University.
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