November GeoRoundUp: the best of the Earth sciences from around the web

November GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, major geoscience headlines, as well as unique and quirky research, this monthly column aims to bring you the latest Earth and planetary science news from around the web.

Major stories

Earth’s red and rocky neighbor has been grabbing a significant amount of attention from the geoscience media this month. We’ll give you the rundown on the latest news of Mars.

The NASA-led InSight lander, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, touched down on the Red Planet’s surface last week, causing the space agency’s Jet Propulsion Laboratory (JPL) control room to erupt in applause, fist pumps, and cool victory handshakes.

The lander, equipped with a heat probe, a radio science instrument and a seismometer, will monitors the planet’s deep interior. Currently, no other planet besides our own has been analysed in this way.

While scientists know quite a bit about the atmosphere and soil level of Mars, their understanding of the planet’s innerworkings, figuratively and literally, only scratches the surface. “We don’t know very much about what goes on a mile below the surface, much less 2,000 miles below the surface down to the center,” explains Bruce Banerdt, a scientist at JPL, to the Atlantic.

By probing into Mars’ depths, researchers hope the mission gives insight into the evolution of our solar system’s rocky planets in their early stages and helps explain why Earth and Mars formed such different environments, despite originating from the same cloud of dust.

“Our measurements will help us turn back the clock and understand what produced a verdant Earth but a desolate Mars,” Banerdt said recently in a press release.

The InSight lander launched from Earth in May this year, making its way to Mars over the course of seven months. Once reaching the planet’s upper atmosphere, the spacecraft decelerated from about 5,500 to 2.4 metres per second, in just about six minutes. To safely slow down its descent, the lander had to use a heatshield, a parachute and retro rockets.

“Although we’ve done it before, landing on Mars is hard, and this mission is no different,” said Rob Manning, chief engineer at JPL, during a livestream. “It takes thousands of steps to go from the top of the atmosphere to the surface, and each one of them has to work perfectly to be a successful mission.”

This artist’s concept depicts NASA’s InSight lander after it has deployed its instruments on the Martian surface. Credit: NASA/JPL-Caltech

The InSight lander is currently situated on Elysium Planitia, a plane near the planet’s equator also known by the mission team as the “biggest parking lot on Mars.” Since landing, the robot has taken its first photos, opened its solar panels, and taken preliminary data. It will spend the next few weeks prepping and unpacking the instruments onboard.

The devices will be used to carry out three experiments. The seismometers will listen for ‘marsquakes,’ which can offer clues into the location and composition of Mars’ rocky layers. The thermal probe will reveal how much heat flows out of the planet’s interior and hopefully show how alike (or unalike) Mars is to Earth. And finally, radio transmissions will demonstrate how the planet wobbles on its axis.

In other news, NASA has also chosen a landing site for the next Mars rover, which is expected to launch in 2020. The space agency has announced that the rover will explore and take rock samples from Jezero crater, one of the three locations shortlisted by scientists. The crater is 45 kilometres wide and at one point had been filled with water to a depth of 250 metres. The sediment and carbonate rocks left behind could offers clues on whether Mars had sustained life.

What you might have missed

By analysing radar scans and sediment samples, a team of scientists have discovered a massive crater, hidden underneath more than 900 metres of ice in northwest Greenland. After surveying the site, scientists say it’s likely that a meteorite created the sometime between 3 million and 12,000 years ago.

The depression under Hiawatha Glacier is 31 kilometres wide, big enough to hold the city of Paris. At this size, the crater is one of the top 25 largest craters on Earth; it’s also the first to be found under ice. An impact of this size significant mark on the Earth’s environment. “Such an impact would have been felt hundreds of miles away, would have warmed up that area of Greenland and may have rained rocky debris down on North America and Europe,” said Jason Daley from Smithsonian Magazine.

Links we liked

The EGU Story

This month, we have announced changes to the EGU General Assembly 2019 schedule, which aim to give more time for all presentation types. Check our news announcement for more information. In other news, we have opened applications to the EGU General Assembly 2019 mentoring programme, and are advertising a job opportunity for geoscientists with science communication experience to work at the meeting.

Also this month, we opened the call for applications for EGU Public Engagement Grants, and have announced the creation of the EGU Working Group on Diversity and Equality. Finally, we’ve published a press release on a new study that looked into whether data on seabird behavior could be used to track the ocean’s currents.

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

Plate Tectonics and Ocean Drilling – Fifty Years On

Plate Tectonics and Ocean Drilling – Fifty Years On

What does it take to get a scientific theory accepted? Hard facts? A strong personality? Grit and determination? For many Earth Scientists today it can be hard to imagine the academic landscape before the advent of plate tectonics. But it was only fifty years ago that the theory really became cemented as scientific consensus. And the clinching evidence was found in the oceans.

Alfred Wegener had proposed the theory of continental drift back in 1912. The jigsaw-fit of the African and South American continents led him to suppose that they must once have been joined together. But in the middle of the century, the idea fell out of favour; some even referred to it as a “fairy-tale”.

It was not until the discovery of magnetic reversals on the seafloor in the early 1960s that the theory began to sound plausible again. If brand new ocean crust was being formed at the mid-ocean ridges, then the rocks either side of the ridge should show symmetrical patterns of magnetism. Fred Vine and Drummond Matthews, geologists at the University of Cambridge in the UK, were the first to publish on the idea of seafloor spreading in 1963.

But plate tectonics was still not the only theory on the market. The expanding Earth hypothesis held that the positions of the continents could be explained by an overall expansion in the volume of the Earth. Numerous twentieth-century physicists subscribed to such a view. Or, similarly, the shrinking Earth theory proposed that the whole planet had once been molten. Mountain ranges would then be formed as the Earth cooled and the crust crumpled.

Helmut Weissert, President of the EGU Stratigraphy, Sedimentology and Palaeontology Division, remembers the difficult exchanges that took place whilst he was a student at ETH Zürich in the late 1960s. “Earth-science-wise it was a hot time,” he recalls. “In Bern University they did not teach plate tectonics. We did not have a course on plate tectonics either. I probably first heard about plate tectonics in [my] second or third year.”

Weissert especially remembers Rudolf Trümpy, professor of Alpine geology at ETH at the time, saying that plate tectonics sounds interesting, but it does not work for the Alps. Meanwhile, younger voices at ETH, postdocs and lecturers, were becoming increasingly convinced by plate tectonic theory.

Weissert soon found himself in the midst of the controversy as his own research had a direct bearing on the debate. “I had an interesting diploma topic,” says Weissert. “I worked on continental margin successions and associated serpentinites.” Serpentinites are green-coloured rocks that are full of the water-rich mineral serpentine, and therefore must have formed on the ocean floor. The fact that Weissert was finding them in Davos, at the top of the Alps, was a good indication that modern-day Switzerland had once been part of the oceans. As Weissert succinctly puts it, “green rocks were ocean”.

The observed and calculated magnetic profile for the seafloor across the East Pacific Rise, showing symmetrical patterns of magnetism. (Image Credit: U.S. Geological Survey. Distributed via Wikimedia Commons)

By 1967, interest in the theory of plate tectonics had snowballed. When the Deep Sea Drilling Project (DSDP) was launched the following year, it had its sights firmly set on finding evidence that would definitively either confirm or reject the hypothesis of seafloor spreading.

The DSDP research vessel, the Glomar Challenger, set sail from Texas in March 1968. By its third leg it had drilled 17 holes at 10 sites along the mid-Atlantic ocean ridge and was already producing results that looked like they would confirm Wegener’s theory of continental drift. “After a few legs it was clear that the seafloor spreading hypothesis was tested and proven,” remembers Weissert.

There were only eight scientists on board, but two or three of them were working on the stratigraphy of the seafloor sediments. “The stratigraphy was superb,” explains Weissert. “You have the very young [sediments near the ridge] and then at the edges of the ocean the Jurassic sediments. If you have aging crust then you have aging sediment, so the hypothesis was very clear.” If the sediments got progressively older on moving away from the ridge, then so must the crust, a sure sign that new ocean floor was being created at the ridge.

Karen Heywood, EGU Division President in Ocean Sciences, remembers how her own fascination with the theory of plate tectonics ended up sparking her career in physical oceanography. Heywood began as a physics student at the University of Bristol in the 1980s. “They said we had to write an essay on the historical development of an idea in physics,” she recalls. “I did the development of the theory of plate tectonics and seafloor spreading. I wrote this essay all about Alfred Wegener.”

“This essay inspired me to think about earth sciences,” she says. “The idea that you could apply physics to the real world was amazing. It got me into oceanography.”

Heywood went on to establish her career at the University of East Anglia (UEA), where she became the first female professor of Physical Oceanography in the UK. “I went to the UEA and Fred Vine was there. It brought me back full circle. I could not believe that this was Fred Vine, who had discovered the magnetic stripes. This was the real person and that was amazing… it was the same person that I had read about and written about in my essay as an undergraduate in the 80s.”

There were clearly strong personalities on both sides of the debate about plate tectonics, but Weissert is pragmatic about the progress of science. “You have to accept that you are part of a scientific development. Everybody makes hypotheses… We all make mistakes. We all learn. We all improve.”

Indeed, many years later, in 2001, Trümpy wrote what Weissert calls “a beautiful small article” entitled Why plate tectonics was not invented in the Alps. Trümpy magnanimously writes, “Shamefacedly, I must admit that I was not among the first Alpine geologists to grasp the promise of the new tectonics.”  And yet, he continues, “to the Alps, plate tectonics brought a better understanding”. The humans and the science move on together.

By Tim Middleton, EGU 2018 General Assembly Press Assistant


DSDP Phase: Glomar Challenger, International Ocean Discovery Program

Trümpy, R., Why plate tectonics was not invented in the Alps, International Journal of Earth Sciences, Volume 90, Issue 3, pp 477–483, 2001.

How to make a planet habitable

How to make a planet habitable

Exoplanets without plate tectonics could harbour life, contrary to previous belief

For a planet to be habitable, it needs a stable climate. On Earth, the movement of tectonic plates ensures old crust is recycled and new crust is created and weathered. This cycling of rock consequently overturns the planet’s carbon, which keeps the climate in check.

While we have plate tectonics on Earth, many other rocky planets have what is called a ‘stagnant lid’. In this system, there is one solid plate wrapped around the planet, and the mantle circulates beneath it. The same recycling processes found on Earth don’t occur in these stagnant lid planets, preventing regulation of the carbon cycle and generating an inhospitable climate, or so scientists thought.

It is often claimed that plate tectonics is a requirement for a habitable climate, but research presented at the EGU General Assembly in Vienna suggests that some of these stagnant lid planets may be habitable after all.

Volcanic activity on stagnant lid planets could provide enough fresh rock for weathering to operate like it does on Earth, suggests Bradford Foley, a geologist from Pennsylvania State University in University Park, Pennsylvania. This means that simply burying the crust by lava flows could recycle enough CO2 to regulate the climate.

In their early history, the rocky surfaces of stagnant lid planets release gases that form an atmosphere. These young planets are also peppered with volcanoes that produce fresh, weatherable rock. Combined, these processes create a carbon cycle and, if the conditions are right, they can maintain a stable climate for long periods of time.

By modelling processes on stagnant lid planets that are similar in size to Earth, Foley was able to work out what conditions would create a habitable climate. The balance lies in striking the right amount of degassing, the process in which volcanoes release gas into the atmosphere. Not enough would lead to full surface glaciation, as too thin an atmosphere would make the planet extremely cold. On the other hand, too much degassing would generate a thick, CO2-rich atmosphere, leading to an incredibly hot environment.

There are two planetary budgets to take into account: carbon and heat. “We found a sweet spot, around Earth’s total amount of carbon to an order of magnitude less than that,” says Foley. That’s about 10 times less carbon than there is in Earth’s atmosphere, mantle and crust combined. Much lower, and there’s not enough of an atmosphere to keep the planet warm.

The other important consideration is the planet’s heat budget. As radioactive elements decay, they produce heat, and the more of these heat-producing elements a planet has, the bigger its heat budget. If a stagnant lid planet has fewer heat-producing elements than Earth, volcanic activity dies off pretty quickly and the planet cools off. “Without volcanism, the planet would most likely freeze over,” Foley adds. The more heat-producing elements there are, the longer volcanism can last. This means that, potentially, habitable climates could last longer too.

“Planets with two to two and a half times the heat budget for Earth can have potentially habitable climates lasting for three to four billion years, plenty enough time for developing life,” Foley explains.

According to Foley, the model could be used to guide future exoplanet missions. If we know how old a planet is and have information on its heat budget we can work out its chances of being habitable, says Foley. Both of these can be worked out using observations from Earth and could be used to create new targets for planetary exploration.

Lena Noack, a planetary scientist and Junior Professor at Free University Berlin who was not involved in the study, shared her thoughts on the research: “it shows, even though plate tectonics would typically always be considered as a better indicator for habitability, stagnant lid planets do not need to be ruled out. A good example is Mars; it was locally habitable early on in its history, but if it would just be a little bit larger, of Earth size as in Foley’s study, it is not difficult to imagine that it would be quite a habitable place at present day.”

By Sara Mynott


Foley,  B. Climate Stability and Habitability of Earth-like Stagnant Lid Planets. EGU General Assembly. 2018. 

Foley, B. and Smye, A. Carbon cycling and habitability of Earth-size stagnant lid planetsarXiv:1712.03614v1. 2017.

Imaggeo on Mondays: Tones of sand

Tones of Sand

With rocks dating as far back as the Precambrian, mountain building events, violent volcanic eruptions and being covered, on and off, by shallow seas, Death Valley’s geological history is long and complex.

Back in the Cenozoic (65 to 30 million years ago), following a turbulent period which saw the eruption of volcanoes (which in time would form the Sierra Nevada of California) and regional uplift, Death Valley was a peaceful place. There was no deposition of sediments, nor emplacement of igneous rocks. The valley was being eroded, slowly.

Fast forward a few thousand years, to the Miocene (ca. 27 million years ago) and all that changed. New volcanic eruptions drove the onset of a major extensional event, which saw basins and ranges develop into Death Valley as we know it today.

The tectonics of the region were also complex: the North American plate was riding up and over the Pacific plate, but around the same time as the extension started in the basin, the spreading centre of the Pacific plate intersected with the Fallon Plate, splitting it in half. The northern section became the Juan de Fuca plate and the San Andreas Fault was created between the remnants of the subduction zone.

The Panamint Range – a fault-block mountain range on the edge of the Mojave Desert – formed as a result of the powerful tectonic events. Initially, it rode over and piggy backed on top of The Black Mountains, before sliding towards the west.  As the mountain ranges slid apart, the valleys lost height too and started receiving sediment.

The sediment influx happens to this day, as evidenced in today’s Imaggeo on Monday’s photograph, taken by Marc Girons Lopez, a hydrologist at Uppsala University (Sweden).

“The photograph was taken from Dante’s View viewpoint terrace and shows the Death Valley on the foreground and the Panamint Range on the background,” describes Marc.

At present, a series of alluvial fans drain the Panamint Range, forming triangle-shaped deposits of gravel, sand and silt. These fans are formed through the deposition of sediments eroded from the Panamint Range during flash flood events.

Marc says that “the colour of the sand forming the alluvial fans relates to their age; the clearer the tones the younger their age.”

The salt flats in the foreground, which are covered in salt and other minerals, are the remnants of Lake Manly, a landlocked lake system which drained to no other bodies of water such as rivers or oceans. The lake was present during the Pleistocene era (2.85 million years ago) and slowly evaporated as the region progressively desertified. The evaporitic salts have been exploited in modern times.


If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at