Opinion: Worthless mining waste could suck CO₂ out of the atmosphere and reverse emissions
By Anonymous from University of Cambridge - Department of Earth Sciences. Published on Apr 20, 2017.
The Paris Agreement commits nations to limiting global warming to less than 2˚C by the end of the century. However, it is becoming increasingly apparent that, to meet such a massive challenge, societies will need to do more than simply reduce and limit carbon emissions. It seems likely that large scale removal of greenhouse gases from the atmosphere may be called for: so-called “negative emissions”.
One possibility is to use waste material from mining to trap CO₂ into new minerals, locking it out of the atmosphere. The idea is to exploit and accelerate the same geological processes that have regulated Earth’s climate and surface environment over the 4.5 billion years of its existence.
Across the world, deep and open-pit mining operations have left behind huge piles of worthless rubble – the “overburden” of rock or soil that once lay above the useful coal or metal ore. Often, this rubble is stored in dumps alongside tiny fragments of mining waste – the “tailings” or “fines” left over after processing the ore. The fine-grained waste is particularly reactive, chemically, since more surface is exposed.
A lot of energy is spent on extracting and crushing all this waste. However, breaking rocks into smaller pieces exposes more fresh surfaces, which can react with CO₂. In this sense, energy used in mining could itself be harvested and used to reduce atmospheric carbon.
This is one of the four themes of a new £8.6m research programme launched by the UK’s Natural Environment Research Council, which will investigate new ways to reverse emissions and remove greenhouse gases from the atmosphere.
The process we want to speed up is the “carbonate-silicate cycle”, also known as the slow carbon cycle. Natural silicate rocks like granite and basalt, common at Earth’s surface, play a key part in regulating carbon in the atmosphere and oceans by removing CO₂ from the atmosphere and turning it into carbonate rocks like chalk and limestone.
Atmospheric CO₂ and water can react with the silicate rocks to dissolve elements they contain like calcium and magnesium into the water, which also soaks up the CO₂ as bicarbonate. This weak solution is the natural river water that flows to the oceans, which hold more than 60 times more carbon than the atmosphere. It is here, in the oceans, that the calcium and bicarbonate can recombine, over millions of years, and crystallise as calcite or chalk, often instigated by marine organisms as they build their shells.
Today, rivers deliver hundreds of millions of tonnes of carbon each year into the oceans, but this is still around 30 times less than the rate of carbon emission into the atmosphere due to fossil fuel burning. Given immense geological time scales, these processes would return atmospheric CO₂ to its normal steady state. But we don’t have time: the blip in CO₂ emissions from industrialisation easily unbalances nature’s best efforts.
The natural process takes millions of years – but can we do it in decades? Scientists looking at accelerated mine waste dissolution will attempt to answer a number of pressing questions. The group at Cambridge which I lead will be investigating whether we can speed up the process of silicate minerals from pre-existing mine waste being dissolved into water. We may even be able to harness friendly microbes to enhance the reaction rates.
Another part of the same project, conducted by colleagues in Oxford, Southampton and Cardiff, will study how the calcium and magnesium released from the silicate mine waste can react back into minerals like calcite, to lock CO₂ back into solid minerals into the geological future.
Whether this can be done effectively without requiring further fossil fuel energy, and at a scale that is viable and effective, remains to be seen. But accelerating the reaction rates in mining wastes should help us move at least some way towards reaching our climate targets.
Could waste material from mining be used to trap CO2 emissions? A new £8.6 million research programme will investigate the possibilities. Simon Redfern (Department of Earth Sciences) explains, in this article from The Conversation.
Drones used to analyse ash clouds from Guatemalan volcano
By cjb250 from University of Cambridge - Department of Earth Sciences. Published on Apr 11, 2017.
During a ten-day research trip, the team carried out many proof-of-concept flights at the summits of both Volcán de Fuego and Volcán de Pacaya in Guatemala. Using lightweight modern sensors they measured temperature, humidity and thermal data within the volcanic clouds and took images of multiple eruptions in real-time.
This is one of the first times that bespoke fixed-wing unmanned aerial vehicles (UAVs) have been used at a volcano such as Fuego, where the lack of close access to the summit vent has prevented robust gas measurements. Funding from the Cabot Institute has helped the team to develop technologies to enable this capability. The UAVs were successfully flown at distances of up to 8 km away, and at a height of over 3 km above the launch site.
The group plan to return to Guatemala later in the year with a wider range of sensors including a gas analyser, a four-stage filter pack; carbon stubs for ash sampling; thermal and visual cameras, and atmospheric sensors.
Dr Emma Liu, a volcanologist from the Department of Earth Sciences at Cambridge, said: “Drones offer an invaluable solution to the challenges of in-situ sampling and routine monitoring of volcanic emissions, particularly those where the near-vent region is prohibitively hazardous or inaccessible.
“These sensors not only help to understand emissions from volcanoes, they could also be used in the future to help alert local communities of impending eruptions – particularly if the flights can be automated.”
Dr Kieran Wood, Senior Research Associate in the Department of Aerospace Engineering at Bristol, added: “Even during this initial campaign we were able to meet significant science and engineering targets. For example, multiple imaging flights over several days captured the rapidly changing topography of Fuego’s summit. These showed that the volcano was erupting from not just one, but two active summit vents.”
Taking time out from their sample flights, the research group also used their aircraft to map the topology of a barranca and the volcanic deposits within it. These deposits were formed by a recent pyroclastic flow, a fast-moving cloud of superheated ash and gas, which travelled down the barranca from Fuego. The data captured will assist in modelling flow pathways and the potential impact of future volcanic eruptions on nearby settlements.
Dr Matt Watson, Reader in Natural Hazards in the School of Earth Sciences at Bristol, said: “This is exciting initial research for future investigations, and would not be possible without a very close collaboration between volcanology and engineering.”
Adapted from a press release by the University of Bristol.
A team of volcanologists and engineers from the Universities of Cambridge and Bristol has collected measurements from directly within volcanic clouds, together with visual and thermal images of inaccessible volcano peaks.
Opinion: The rapidly populating coastal region from the Gulf to Pakistan faces a huge tsunami risk
By cjb250 from University of Cambridge - Department of Earth Sciences. Published on Apr 07, 2017.
That tsunamis can cause death and devastation has become painfully clear over the past two decades. On Boxing Day, 2004, a magnitude 9 earthquake off the coast of Sumatra caused waves several metres high to devastate the Indian Ocean – killing more than 230,000 people in 14 countries. In 2011, another magnitude 9 earthquake, this time off Japan, produced waves up to 20 metres in height, flooding the Fukushima nuclear reactor. It killed more than 15,000 people.
A new study, published in Geophysical Journal International, by my colleagues and me suggests that a 1,000km long fault at the northern end of the Arabian Sea may pose a similar threat.
The Makran, as the southern coastal region of Iran and Pakistan is known, is a subduction zone. In such regions, one of the Earth’s tectonic plates is dragged beneath another, forming a giant fault known as a “megathrust”. As the plates move past each other, they can get stuck, causing stress to build up. At some point the stress becomes high enough that the megathrust breaks in an earthquake.
This was exactly what caused the Sumatra 2004 and Tohoku 2011 earthquakes. When a megathrust moves suddenly, the whole seafloor is offset and the water has to move out of the way over a huge area. This sets off waves with particular characteristics that can cross entire oceans: tsunamis. The phenomenon, along with their potentially large size, makes subduction zone earthquakes particularly dangerous.
But just because a part of a subduction zone produces earthquakes doesn’t mean that the whole megathrust can move in one go. We often see that stress builds up at different rates on different parts of the fault, with some parts sliding smoothly past each other. How much of a megathrust can move in one go is important because it determines the size of the resulting earthquake. The amount that the Makran megathrust can move in earthquakes has been a longstanding question, but the hostile climate and challenging politics of the region have made research there difficult.
We know that the eastern part of the Makran megathrust (in Pakistan) can produce large earthquakes. A magnitude 8.1 quake off the coast of western Pakistan in 1945 caused a tsunami which killed about 300 people along the coasts of Pakistan and Oman. There have been several smaller earthquakes on the megathrust since, including a magnitude 6 in February this year.
If the western part of the Makran (in Iran) also produces earthquakes – and the whole Makran megathrust were to move in one go – it could produce a magnitude 9 earthquake, similar to those in Sumatra and Tohoku.
However, we have never actually recorded a subduction earthquake in this part of Makran. In fact, there are only records of one candidate quake from 1483 – and the actual location of this is disputed. But it’s important to keep in mind that just because we haven’t seen an earthquake doesn’t mean that there couldn’t be one – particularly since the intervals between earthquakes are often hundreds or thousands of years. Historically, not many people have lived in the remote Iranian Makran, a desert which killed Alexander the Great’s army. So earthquakes might simply not have been documented.
We used new data to look for tell-tale signs of a possible earthquake. Imagine a piece of paper on a table. If you hold one end and push the other end towards it, the paper crumples up and the distance between the two ends gets shorter. If you let go, the paper flattens out. The fixed end is like a megathrust which is stuck. Indeed, if the Arabian plate is stuck, and stress is building up, southern Iran will be squeezed and shortened. We can look for evidence of this shortening by using a more accurate version of the GPS systems found in smartphones. My coauthors from the National Cartographic Centre in Iran have set up a network of GPS stations to measure how fast different parts of Iran are moving relative to Arabia.
We found that the velocities fit with Iran being shortened near the coast, suggesting that stress is indeed building up – and meaning there could be a large subduction earthquake in the future. This fits with recent work looking at large boulders along the coast of Oman, thought to have been deposited by tsunamis. The locations of these boulders suggest that the tsunami which brought them there would need to have come from a subduction earthquake, either in western Makran or along the entire subduction zone – including Pakistan. These boulders were probably deposited in the last 5,000 years, but we can’t know for sure.
This is a hazard that people need to be aware of, particularly those living in coastal regions around the Arabian Sea. Rapid urbanisation along the Omani and Pakistani coasts in recent years has increased the population exposed to earthquakes and tsunamis in the Makran. Karachi, at the eastern end of the subduction zone, is now a megacity and home to around 25m people. Much of Muscat, the Omani capital, is less than 10 metres above sea level, making it vulnerable to tsunamis. The port of Gwadar in Pakistan, which was badly damaged in a 1945 earthquake, is also undergoing massive development.
To help protect these people, and make sure that they are properly prepared, we need to understand this hazard better. Education and early warning are both key – exercises testing the Indian Ocean Tsunami Warning System are a step in the right direction, especially if they engage the public.
At the moment, we can only say that a large earthquake in the Makran is consistent with the limited data which we have available. By continuing to work with scientists in Iran and Pakistan to make more measurements I hope that in the future we will have a much better idea of what to expect from this subduction zone.
In recent years, tsunamis have devastated coastal regions. Writing in The Conversation, Camilla Penney, PhD Candidate in Geophysics at University of Cambridge, looks at the risks faced by Gulf states and what can be done to mitigate them.
Opinion: Geologists unveil how Britain first separated from Europe – and it was catastrophic
By cjb250 from University of Cambridge - Department of Earth Sciences. Published on Apr 06, 2017.
As Brexit looms, Earth scientists have uncovered evidence of Britain’s original split from mainland Europe. Almost half a million years ago, according to new data, water suddenly started cascading over the narrow strip of land that joined England and France – putting pressure on a chalk bridge.
Researchers show that, as a result, this ridge – a natural dam that separated the North Sea from the English Channel – was catastrophically ruptured hundreds of thousands of years later in a two-stage process, ultimately setting Britain’s insular environment in stone. Their results are reported in Nature Communications.
So where did all the water that caused this geological disaster come from? The scientists, from UK, Belgium and France, base their conclusions on a line of deep plunge pools (basins excavated by intense waterfalls) and a network of channels cut in the sea floor south-west of the ridge line. They deduce that these were first formed some 450,000 years ago as a lake of glacial melt water to the north-east in the North Sea basin (the depression where the north sea sits today, some of which was dry land back then) spilled over into what is today the English Channel.
However, exactly why the glacial lake suddenly spilt over remains unknown. One possibility is that part of its ice sheet broke off, causing a surge that prompted the water to flow over. The 33km long land bridge at Dover Strait formed part of an icy landscape at the time. According to the researchers, it looked “more like the frozen tundra in Siberia than the green environment we know today”.
The loose gravel that fills the seafloor plunge pools was first noticed 50 years ago. Indeed, the channel tunnel had to be rerouted to avoid them during its construction. There has long been speculation that they were associated with the remains of the land bridge that formed an ancient route between UK and Europe – and now we finally have some evidence to back this up.
The plunge pools themselves are huge, drilling down some 100 metres into the solid bedrock and measuring several kilometres across. The waterfalls that formed them are estimated to have been 100 metres high, as we know the land bridge stood high above the surrounding landscape.
Second sudden destruction
It seems Dover Strait may have gone through two breaches. The first one, about 450,000 years ago, was rather modest and formed a smaller channel than the one we see today. But the authors suggest that a second, more catastrophic breach subsequently occurred – possibly hundreds of thousands of year later, irrevocably separating Britain from Europe.
This final collapse of the land bridge is marked out by a larger seafloor channel named the Lobourg Channel, which cuts through the earlier structures. This appears to have been carved by a major cataclysmic flood from the North Sea into the English Channel. The timings of the two-stage erosion, including the final destruction of the connecting bridge, are uncertain, but mollusc shells found either side of the breach indicate that it was complete at least 100,000 years ago.
The latest observations are the result of a broad marine geophysics campaign to tackle the problem. Ship-based seismic surveys of the floor of the English Channel have been combined with a type of sonar to provide an astoundingly detailed picture of the sea floor and its sub-surface. Uncertainty remains over the exact timings of each of the events, and researchers have set their sights on drilling into the sea floor to retrieve samples from the plunge pool sediments to determine their precise ages.
The erosion of the land bridge hundreds of thousands of years ago set Britain on its path to becoming an island nation. Subsequent changes in sea level at the end of that ancient ice age further confirmed its insularity, and Britain’s connection to mainland Europe was lost.
Brexit won't be the first time Britain has left Europe, says Simon Redfern, professor in Earth Sciences at University of Cambridge writing for The Conversation. Almost half a million years ago we experienced a catastrophic separation.
The man who split the dinosaurs in two – Harry Govier Seeley
From Department of Earth Sciences. Published on Mar 23, 2017.The talk was titled ‘On the Classification of the Fossil Animals Commonly Named Dinosaurs’ and it was given in 1887 by Harry Govier Seeley, Professor of Geology at King’s College, London. Seeley argued that the ‘terrible lizards’, which were becoming increasingly popular at the time, could be simply divided into two great groups – the Saurischia and the Ornithischia based on differences in their hip structure.
New study shakes the roots of the dinosaur family tree
By ps748 from University of Cambridge - Department of Earth Sciences. Published on Mar 22, 2017.
For 130 years palaeontologists have been working with a classification system in which dinosaur species have been placed in to two distinct categories: Ornithischia and Saurischia. But now, after careful analysis of dozens of fossil skeletons and tens of thousands of anatomical characters, the researchers have concluded that these long-accepted familial groupings may, in fact, be wrong and that the traditional names need to be completely altered.
The classification of dinosaurs dates back to Victorian times. Dinosaurs were first recognised as a unique group of fossil reptiles in 1842 as a result of the work of the anatomist, Professor Richard Owen (who later went on to found the Natural History Museum in London). Over subsequent decades, various species were named as more and more fossils were found and identified. During the latter half of the 19th century it was realised that dinosaurs were anatomically diverse and attempts were made to classify them into groups that shared particular features.
It was Harry Govier Seeley, a palaeontologist trained in Cambridge under the renowned geologist Adam Sedgwick, who determined that dinosaurs fell quite neatly into two distinct groupings, or clades; Saurischia or Ornithischia. This classification was based on the arrangement of the creatures’ hip bones and in particular whether they displayed a lizard-like pattern (Saurischia) or a bird-like one (Ornithischia).
As more dinosaurs were described it became clear that they belonged to three distinct lineages; Ornithischia, Sauropodomorpha and Theropoda. In 1887 Seeley placed the sauropodomorphs (which included the huge ‘classic’ dinosaurs such as Diplodocus and Brontosaurus) together with the theropods (which included T. rex), in the Saurischia. The ornithischians and saurischians were at first thought to be unrelated, each having a different set of ancestors, but later study showed that they all evolved from a single common ancestor.
This new analysis of dinosaurs and their near relatives, published today in the journal Nature, concludes that the ornithischians need to be grouped with the theropods, to the exclusion of the sauropodomorphs. It has long been known that birds (with their obviously ‘bird-like’ hips) evolved from theropod dinosaurs (with their lizard-like hips). However, the re-grouping of dinosaurs proposed in this study shows that both ornithischians AND theropods had the potential to evolve a bird-like hip arrangement- they just did so at different times in their history.
Lead author, Matthew Baron, says:
“When we started our analysis, we puzzled as to why some ancient ornithischians appeared anatomically similar to theropods. Our fresh study suggested that these two groups were indeed part of the same clade. This conclusion came as quite a shock since it ran counter to everything we’d learned.”
“The carnivorous theropods were more closely related to the herbivorous ornithischians and, what’s more, some animals, such as Diplodocus, would fall outside the traditional grouping that we called dinosaurs. This meant we would have to change the definition of the ‘dinosaur’ to make sure that, in the future, Diplodocus and its near relatives could still be classed as dinosaurs.”
The revised grouping of Ornithischia and Theropoda has been named the Ornithoscelida which revives a name originally coined by the evolutionary biologist, Thomas Henry Huxley in 1870.
Co-author, Dr David Norman, of the University of Cambridge, says:
“The repercussions of this research are both surprising and profound. The bird-hipped dinosaurs, so often considered paradoxically named because they appeared to have nothing to do with bird origins, are now firmly attached to the ancestry of living birds.”
For 130 years palaeontologists have considered the phylogeny of the dinosaurs in a certain way. Our research indicates they need to look again at the creatures’ evolutionary history. This is simply science in action. You draw conclusions from one body of evidence and then new data or theories present themselves and you have to suddenly reconsider and adapt your thinking. All the major textbooks covering the topic of the evolution of the vertebrates will need to be re-written if our suggestion survives academic scrutiny.”
While analysing the dinosaur family trees the team arrived at another unexpected conclusion. For many years, it was thought that dinosaurs originated in the southern hemisphere on the ancient continent known as Gondwana. The oldest dinosaur fossils have been recovered from South America suggesting the earliest dinosaurs originated there. But as a result of a re-examination of key taxa it’s now thought they could just as easily have originated on the northern landmass known as Laurasia, though it must be remembered that the continents were much closer together at this time.
Co-author, Prof Paul Barrett, of the Natural History Museum, says:
"This study radically redraws the dinosaur family tree, providing a new framework for unravelling the evolution of their key features, biology and distribution through time. If we're correct, it explains away many prior inconsistencies in our knowledge of dinosaur anatomy and relationships and it also highlights several new questions relating to the pace and geographical setting of dinosaur origins".
The research was funded through a Natural Environment Research Council (NERC) CASE studentship.
Matthew Baron et al: 'A new hypothesis of dinosaur relationships and early dinosaur evolution' Nature, 23 March 2017
A short video guide has been prepared by the Natural History Museum to accompany this paper.
More than a century of theory about the evolutionary history of dinosaurs has been turned on its head following the publication of new research from scientists at the University of Cambridge and Natural History Museum in London. Their work suggests that the family groupings need to be rearranged, re-defined and re-named and also that dinosaurs may have originated in the northern hemisphere rather than the southern, as current thinking goes.
When did making mountains the modern way begin?
From Department of Earth Sciences. Published on Mar 14, 2017.What with ‘tectonic shifts’ and ‘tectonic proportions’, the processes and terminology of Earth’s major structural change or tectonism have invaded everyday language. Now geological research is adding a new dimension – ‘changing tectonic regimes’, the US presidency comes to mind. So what is a ‘change in tectonic regime’?
Simple rule predicts when an ice age ends
From Department of Earth Sciences. Published on Feb 27, 2017.A simple rule can accurately predict when Earth’s climate warms out of an ice age, according to a new study published in Nature. Researchers from UCL, University of Cambridge and University of Louvain have combined existing ideas to solve the problem of which solar energy peaks in the last 2.6 million years led to the melting of the ice sheets and the start of a warm period.
Fossil corset-animals (loriciferans) help solve Darwin’s dilemma
From Department of Earth Sciences. Published on Feb 13, 2017.The living corset-animals (loriciferans) are a remarkable group of miniscule, seabed dwelling creatures, which were first found in the 1980s. Now, the discovery by palaeontologists Tom Harvey and Nick Butterfield of the loriciferans’ deep ancestry in 490 million year old Cambrian strata is helping to rewrite the story of the Cambrian explosion of life and resolve what is known as Darwin’s dilemma.
Earth Sciences students winning prizes
From Department of Earth Sciences. Published on Feb 13, 2017.Congratulations to our students who have recently won prizes.
Tools of the Trade
From Department of Earth Sciences. Published on Feb 13, 2017.A display showcasing a selection of the Sedgwick Museum’s unique historic collection of geological hammers.
The bicentenary of a pioneering account of the Geology of Cambridgeshire
From Department of Earth Sciences. Published on Feb 13, 2017.The first account of the geology of Cambridgeshire was published 200 years ago. Written by the Reverend Professor John Hailstone FRS (1759-1847), the ‘Outline of the Geology of Cambridgeshire’ appeared in the third volume of the Transactions of the Geological Society of London.
Bag-like sea creature was humans’ oldest known ancestor
By tdk25 from University of Cambridge - Department of Earth Sciences. Published on Jan 30, 2017.
Researchers have identified traces of what they believe is the earliest known prehistoric ancestor of humans – a microscopic, bag-like sea creature, which lived about 540 million years ago.
Named Saccorhytus, after the sack-like features created by its elliptical body and large mouth, the species is new to science and was identified from microfossils found in China. It is thought to be the most primitive example of a so-called “deuterostome” – a broad biological category that encompasses a number of sub-groups, including the vertebrates.
If the conclusions of the study, published in the journal Nature, are correct, then Saccorhytus was the common ancestor of a huge range of species, and the earliest step yet discovered on the evolutionary path that eventually led to humans, hundreds of millions of years later.
Modern humans are, however, unlikely to perceive much by way of a family resemblance. Saccorhytus was about a millimetre in size, and probably lived between grains of sand on the seabed. Its features were spectacularly preserved in the fossil record – and intriguingly, the researchers were unable to find any evidence that the animal had an anus.
The study was carried out by an international team of academics, including researchers from the University of Cambridge in the UK and Northwest University in Xi’an China, with support from other colleagues at institutions in China and Germany.
Simon Conway Morris, Professor of Evolutionary Palaeobiology and a Fellow of St John’s College, University of Cambridge, said: “We think that as an early deuterostome this may represent the primitive beginnings of a very diverse range of species, including ourselves. To the naked eye, the fossils we studied look like tiny black grains, but under the microscope the level of detail is jaw-dropping. All deuterostomes had a common ancestor, and we think that is what we are looking at here.”
Degan Shu, from Northwest University, added: “Our team has notched up some important discoveries in the past, including the earliest fish and a remarkable variety of other early deuterostomes. Saccorhytus now gives us remarkable insights into the very first stages of the evolution of a group that led to the fish, and ultimately, to us.”
Most other early deuterostome groups are from about 510 to 520 million years ago, when they had already begun to diversify into not just the vertebrates, but the sea squirts, echinoderms (animals such as starfish and sea urchins) and hemichordates (a group including things like acorn worms). This level of diversity has made it extremely difficult to work out what an earlier, common ancestor might have looked like.
The Saccorhytus microfossils were found in Shaanxi Province, in central China, and pre-date all other known deuterostomes. By isolating the fossils from the surrounding rock, and then studying them both under an electron microscope and using a CT scan, the team were able to build up a picture of how Saccorhytus might have looked and lived. This revealed features and characteristics consistent with current assumptions about primitive deuterostomes.
Dr Jian Han, of Northwest University, said: “We had to process enormous volumes of limestone – about three tonnes – to get to the fossils, but a steady stream of new finds allowed us to tackle some key questions: was this a very early echinoderm, or something even more primitive? The latter now seems to be the correct answer.”
In the early Cambrian period, the region would have been a shallow sea. Saccorhytus was so small that it probably lived in between individual grains of sediment on the sea bed.
The study suggests that its body was bilaterally symmetrical – a characteristic inherited by many of its descendants, including humans – and was covered with a thin, relatively flexible skin. This in turn suggests that it had some sort of musculature, leading the researchers to conclude that it could have made contractile movements, and got around by wriggling.
Perhaps its most striking feature, however, was its rather primitive means of eating food and then dispensing with the resulting waste. Saccorhytus had a large mouth, relative to the rest of its body, and probably ate by engulfing food particles, or even other creatures.
A crucial observation are small conical structures on its body. These may have allowed the water that it swallowed to escape and so were perhaps the evolutionary precursor of the gills we now see in fish. But the researchers were unable to find any evidence that the creature had an anus. “If that was the case, then any waste material would simply have been taken out back through the mouth, which from our perspective sounds rather unappealing,” Conway Morris said.
The findings also provide evidence in support of a theory explaining the long-standing mismatch between fossil evidence of prehistoric life, and the record provided by biomolecular data, known as the “molecular clock”.
Technically, it is possible to estimate roughly when species diverged by looking at differences in their genetic information. In principle, the longer two groups have evolved separately, the greater the biomolecular difference between them should be, and there are reasons to think this process is more or less clock-like.
Unfortunately, before a point corresponding roughly to the time at which Saccorhytus was wriggling in the mud, there are scarcely any fossils available to match the molecular clock’s predictions. Some researchers have theorised that this is because before a certain point, many of the creatures they are searching for were simply too small to leave much of a fossil record. The microscopic scale of Saccorhytus, combined with the fact that it is probably the most primitive deuterostome yet discovered, appears to back this up.
The findings are published in Nature. Reference: Jian Han, Simon Conway Morris, Qiang Ou, Degan Shu and Hai Huang. Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China). DOI: 10.1038/nature21072.
Inset image: Photographs of the fossils show the spectacularly detailed levels of preservation which allowed researchers to identify and study the creature. Credit: Jian Han.
A tiny sea creature identified from fossils found in China may be the earliest known step on an evolutionary path that eventually led to the emergence of humans
Antarctic Ice Sheet study reveals 8,000-year record of climate change
By sjr81 from University of Cambridge - Department of Earth Sciences. Published on Dec 12, 2016.
Results of the study, co-authored by Michael Weber, a paleoclimatologist and visiting scientist at the University of Cambridge, along with colleagues from the USA, New Zealand and Germany, are published this week in the journal Nature.
Global climate models that look at the last several thousand years have failed to account for the amount of climate variability captured in the paleoclimate record, according to lead author Pepijn Bakker, a climate modeller from the MARUM Center for Marine Environmental Studies at the University of Bremen in Germany.
The researchers first turned their attention to the Scotia Sea. “Most icebergs calving off the Antarctic Ice Sheet travel through this region because of the atmospheric and oceanic circulation,” explained Weber. “The icebergs contain gravel that drop into the sediment on the ocean floor – and analysis and dating of such deposits shows that for the last 8,000 years, there were centuries with more gravel and those with less.”
The research team’s hypothesis is that climate modellers have historically overlooked one crucial element in the overall climate system. They discovered that the centuries-long phases of enhanced and reduced Antarctic ice mass loss documented over the past 8,000 years have had a cascading effect on the entire climate system.
Using sophisticated computer modelling, the researchers traced the variability in iceberg calving (ice that breaks away from glaciers) to small changes in ocean temperatures.
“There is a natural variability in the deeper part of the ocean adjacent to the Antarctic Ice Sheet that causes small but significant changes in temperatures,” said co-author Andreas Schmittner, a climate modeller from Oregon State University. “When the ocean temperatures warm, it causes more direct melting of the ice sheet below the surface, and it increases the number of icebergs that calve off the ice sheet.”
Those two factors combine to provide an influx of fresh water into the Southern Ocean during these warm regimes, according to Peter Clark, a paleoclimatologist from Oregon State University, and co-author on the study.
“The introduction of that cold, fresh water lessens the salinity and cools the surface temperatures, at the same time, stratifying the layers of water,” he said. “The cold, fresh water freezes more easily, creating additional sea ice despite warmer temperatures that are down hundreds of meters below the surface.”
The discovery may help explain why sea ice is currently expanding in the Southern Ocean despite global warming, the researchers say.
“This response is well-known, but what is less-known is that the input of fresh water also leads to changes far away in the northern hemisphere, because it disrupts part of the global ocean circulation,” explained Nick Golledge from the University of Wellington, New Zealand, an ice-sheet modeller and study co-author. “Meltwater from the Antarctic won’t just raise global sea level, but might also amplify climate changes around the world. Some parts of the North Atlantic may end up with warmer temperatures as a consequence of part of Antarctica melting.”
Golledge used a computer model to simulate how the Antarctic Ice Sheet changed as it came out of the last ice age and into the present, warm period.
"The integration of data and models provides further evidence that the Antarctic Ice Sheet has experienced much greater natural variability in the past than previously anticipated,” added Weber. “We should therefore be concerned that it will possibly act very dynamically in the future, too, specifically when it comes to projecting future sea-level rise.”
Two years ago Weber led another study, also published in Nature, which found that the Antarctic Ice Sheet collapsed repeatedly and abruptly at the end of the Last Ice Age to 19,000 to 9,000 years ago.
An international team of researchers has found that the Antarctic Ice Sheet plays a major role in regional and global climate variability – a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth.
Curious Objects at the University Library
From Department of Earth Sciences. Published on Nov 07, 2016.Curious Objects – an exhibition of ‘some unusual and unexpected items’ from the University Library’s collection runs from 3 Nov 2016 - 31 March 2017 at the Milstein Exhibition Centre, Cambridge University Library, West Road, Cambridge CB3 9DR. Free entry.
Graduate Research Opportunities
From Department of Earth Sciences. Published on Nov 02, 2016.A full list of PhD topics for students hoping to start PhDs in 2017 with the Cambridge NERC DTP - Earth Sciences are now online.
Fossilised dinosaur brain tissue identified for the first time
By sc604 from University of Cambridge - Department of Earth Sciences. Published on Oct 27, 2016.
An unassuming brown pebble, found more than a decade ago by a fossil hunter in Sussex, has been confirmed as the first example of fossilised brain tissue from a dinosaur.
The fossil, most likely from a species closely related to Iguanodon, displays distinct similarities to the brains of modern-day crocodiles and birds. Meninges – the tough tissues surrounding the actual brain – as well as tiny capillaries and portions of adjacent cortical tissues have been preserved as mineralised ‘ghosts’.
The results are reported in a Special Publication of the Geological Society of London, published in tribute to Professor Martin Brasier of the University of Oxford, who died in 2014. Brasier and Dr David Norman from the University of Cambridge co-ordinated the research into this particular fossil during the years prior to Brasier’s untimely death in a road traffic accident.
The fossilised brain, found by fossil hunter Jamie Hiscocks near Bexhill in Sussex in 2004, is most likely from a species similar to Iguanodon: a large herbivorous dinosaur that lived during the Early Cretaceous Period, about 133 million years ago.
Finding fossilised soft tissue, especially brain tissue, is very rare, which makes understanding the evolutionary history of such tissue difficult. “The chances of preserving brain tissue are incredibly small, so the discovery of this specimen is astonishing,” said co-author Dr Alex Liu of Cambridge’s Department of Earth Sciences, who was one of Brasier’s PhD students in Oxford at the time that studies of the fossil began.
According to the researchers, the reason this particular piece of brain tissue has been so well-preserved is that the dinosaur’s brain was essentially ‘pickled’ in a highly acidic and low-oxygen body of water – similar to a bog or swamp – shortly after its death. This allowed the soft tissues to become mineralised before they decayed away completely, so that they could be preserved.
“What we think happened is that this particular dinosaur died in or near a body of water, and its head ended up partially buried in the sediment at the bottom,” said Norman. “Since the water had little oxygen and was very acidic, the soft tissues of the brain were likely preserved and cast before the rest of its body was buried in the sediment.”
Working with colleagues from the University of Western Australia, the researchers used scanning electron microscope (SEM) techniques in order to identify the tough membranes, or meninges, that surrounded the brain itself, as well as strands of collagen and blood vessels. Structures that could represent tissues from the brain cortex (its outer layer of neural tissue), interwoven with delicate capillaries, also appear to be present. The structure of the fossilised brain, and in particular that of the meninges, shows similarities with the brains of modern-day descendants of dinosaurs, namely birds and crocodiles.
In typical reptiles, the brain has the shape of a sausage, surrounded by a dense region of blood vessels and thin-walled vascular chambers (sinuses) that serve as a blood drainage system. The brain itself only takes up about half of the space within the cranial cavity.
In contrast, the tissue in the fossilised brain appears to have been pressed directly against the skull, raising the possibility that some dinosaurs had large brains which filled much more of the cranial cavity. However, the researchers caution against drawing any conclusions about the intelligence of dinosaurs from this particular fossil, and say that it is most likely that during death and burial the head of this dinosaur became overturned, so that as the brain decayed, gravity caused it to collapse and become pressed against the bony roof of the cavity.
“As we can’t see the lobes of the brain itself, we can’t say for sure how big this dinosaur’s brain was,” said Norman. “Of course, it’s entirely possible that dinosaurs had bigger brains than we give them credit for, but we can’t tell from this specimen alone. What’s truly remarkable is that conditions were just right in order to allow preservation of the brain tissue – hopefully this is the first of many such discoveries.”
“I have always believed I had something special. I noticed there was something odd about the preservation, and soft tissue preservation did go through my mind. Martin realised its potential significance right at the beginning, but it wasn’t until years later that its true significance came to be realised,” said paper co-author Jamie Hiscocks, the man who discovered the specimen. “In his initial email to me, Martin asked if I’d ever heard of dinosaur brain cells being preserved in the fossil record. I knew exactly what he was getting at. I was amazed to hear this coming from a world renowned expert like him.”
The research was funded in part by the Natural Environment Research Council (NERC) and Christ’s College, Cambridge.
Martin D. Brasier et al.’ Remarkable preservation of brain tissues in an Early Cretaceous iguanodontian dinosaur.’ Earth System Evolution and Early Life: a Celebration of the Work of Martin Brasier. Geological Society, London, Special Publications, 448. (2016). DOI: 10.1144/SP448.3
Researchers have identified the first known example of fossilised brain tissue in a dinosaur from Sussex. The tissues resemble those seen in modern crocodiles and birds.
Cambridge's postgraduate pioneers
By ta385 from University of Cambridge - Department of Earth Sciences. Published on Oct 12, 2016.
Jonny Hanson, Department of Geography
Postgraduate students at Cambridge walk in the footsteps of giants – Francis Crick, Elizabeth Blackburn, Stephen Hawking, Iris Murdoch and Eric Hobsbawm all pursued PhD research at the University.
International team head to Papua New Guinea to measure volcanic carbon degassing
From Department of Earth Sciences. Published on Sep 01, 2016.An international team of scientists is traveling to the islands of Papua New Guinea this September to study degassing from active volcanoes in remote jungles there. Some of these volcanoes are among the most active on Earth, ejecting a significant proportion of global volcanic gases into the atmosphere.
Mistaken Point - Canada's 10th geological World Heritage Site
From Department of Earth Sciences. Published on Aug 02, 2016.The ancient rugged coastline of Mistaken Point on Newfoundland’s Avalon Peninsula face the winds and waves of the Atlantic Ocean. It can be a difficult place to work, but nevertheless it has been a mecca for geologists for over several decades now.
Carbon dioxide can be stored underground for ten times the length needed to avoid climatic impact
By jeh98 from University of Cambridge - Department of Earth Sciences. Published on Jul 28, 2016.
New research shows that natural accumulations of carbon dioxide (CO2) that have been trapped underground for around 100,000 years have not significantly corroded the rocks above, suggesting that storing CO2 in reservoirs deep underground is much safer and more predictable over long periods of time than previously thought.
These findings, published today in the journal Nature Communications, demonstrate the viability of a process called carbon capture and storage (CCS) as a solution to reducing carbon emissions from coal and gas-fired power stations, say researchers.
CCS involves capturing the carbon dioxide produced at power stations, compressing it, and pumping it into reservoirs in the rock more than a kilometre underground.
The CO2 must remain buried for at least 10,000 years to avoid the impacts on climate. One concern is that the dilute acid, formed when the stored CO2 dissolves in water present in the reservoir rocks, might corrode the rocks above and let the CO2 escape upwards.
By studying a natural reservoir in Utah, USA, where CO2 released from deeper formations has been trapped for around 100,000 years, a Cambridge-led research team has now shown that CO2 can be securely stored underground for far longer than the 10,000 years needed to avoid climatic impacts.
Their new study shows that the critical component in geological carbon storage, the relatively impermeable layer of “cap rock” that retains the CO2, can resist corrosion from CO2-saturated water for at least 100,000 years.
“Carbon capture and storage is seen as essential technology if the UK is to meet its climate change targets,” says principle investigator Professor Mike Bickle, Director of the Cambridge Centre for Carbon Capture and Storage at the University of Cambridge.
“A major obstacle to the implementation of CCS is the uncertainty over the long-term fate of the CO2 which impacts regulation, insurance, and who assumes the responsibility for maintaining CO2 storage sites. Our study demonstrates that geological carbon storage can be safe and predictable over many hundreds of thousands of years.”
The key component in the safety of geological storage of CO2 is an impermeable cap rock over the porous reservoir in which the CO2 is stored. Although the CO2 will be injected as a dense fluid, it is still less dense than the brines originally filling the pores in the reservoir sandstones, and will rise until trapped by the relatively impermeable cap rocks.
“Some earlier studies, using computer simulations and laboratory experiments, have suggested that these cap rocks might be progressively corroded by the CO2-charged brines, formed as CO2 dissolves, creating weaker and more permeable layers of rock several metres thick and jeopardising the secure retention of the CO2,” explains lead author Dr Niko Kampman.
“However, these studies were either carried out in the laboratory over short timescales or based on theoretical models. Predicting the behaviour of CO2 stored underground is best achieved by studying natural CO2 accumulations that have been retained for periods comparable to those needed for effective storage.”
To better understand these effects, this study, funded by the UK Natural Environment Research Council and the UK Department of Energy and Climate Change, examined a natural reservoir where large natural pockets of CO2 have been trapped in sedimentary rocks for hundreds of thousands of years. Sponsored by Shell, the team drilled deep down below the surface into one of these natural CO2 reservoirs to recover samples of the rock layers and the fluids confined in the rock pores.
The team studied the corrosion of the minerals comprising the rock by the acidic carbonated water, and how this has affected the ability of the cap rock to act as an effective trap over geological periods of time. Their analysis studied the mineralogy and geochemistry of cap rock and included bombarding samples of the rock with neutrons at a facility in Germany to better understand any changes that may have occurred in the pore structure and permeability of the cap rock.
They found that the CO2 had very little impact on corrosion of the minerals in the cap rock, with corrosion limited to a layer only 7cm thick. This is considerably less than the amount of corrosion predicted in some earlier studies, which suggested that this layer might be many metres thick.
The researchers also used computer simulations, calibrated with data collected from the rock samples, to show that this layer took at least 100,000 years to form, an age consistent with how long the site is known to have contained CO2.
The research demonstrates that the natural resistance of the cap rock minerals to the acidic carbonated waters makes burying CO2 underground a far more predictable and secure process than previously estimated.
“With careful evaluation, burying carbon dioxide underground will prove very much safer than emitting CO2 directly to the atmosphere,” says Bickle.
The Cambridge research into the CO2 reservoirs in Utah was funded by the Natural Environment Research Council (CRIUS consortium of Cambridge, Manchester and Leeds universities and the British Geological Survey) and the Department of Energy and Climate Change.
The project involved an international consortium of researchers led by Cambridge, together with Aarchen University (Germany), Utrecht University (Netherlands), Utah State University (USA), the Julich Centre for Neutron Science, (Garching, Germany), Oak Ridge National Laboratory (USA), the British Geological Survey, and Shell Global Solutions International (Netherlands).
N. Kampman, et al. "Observational evidence confirms modelling of the long-term integrity of CO2-reservoir caprocks" Nature Communications 28 July 2016.
Study of natural-occurring 100,000 year-old CO2 reservoirs shows no significant corroding of ‘cap rock’, suggesting the greenhouse gas hasn’t leaked back out - one of the main concerns with greenhouse gas reduction proposal of carbon capture and storage.
An underestimated Kevan
From Department of Earth Sciences. Published on Jul 21, 2016.Douglas Palmer on the Sedgwick Museum’s giant Pliosaurus cf. kevani in the latest edition of Geoscientist
Oesia – a new tube worm from deep Cambrian times
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Earthquakes Without Frontiers
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Indian High Commissioner's visit
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Congratulations to Dr Peter Friend
From Department of Earth Sciences. Published on Mar 24, 2015.