In 2009, scientists with the Deep Drilling Project were drilling a mile-deep borehole into Iceland's Krafla volcanic caldera when magma suddenly began creeping into the hole. The team had known, based on geophysical surveys, that a large magma body lay about two miles below the surface. But the surveys had failed to warn of molten rock at these shallower depths.
It was a concerning oversight. After all, Krafla is one of the world's most closely monitored volcanic systems, so if volcanologists can't detect shallow magma there, what does that suggest about risk assessments at other volcanoes?
A new study published in Geology explores the potential threats of such hidden magma pools, or "covert silicic magma." The researchers used the 2009 Krafla incident to assess how hidden magma pools form and whether they might pose previously unknown eruptions risks.
The devil's in the magma
To better understand the origins of hidden magma pools, the researchers took magma samples from the 2009 Krafla incident and compared them to seven other recorded eruptions within the Krafla caldera involving rhyolite, a silica-rich type of volcanic rock that's especially explosive.
At first, the team thought the hidden magma pool formed during relatively passive eruptions during the 1980s. But the analysis revealed the samples to be "essentially indistinguishable" from rocks ejected by Krafla's most recent explosive eruption: a mixed hydrothermal-magmatic event that occurred in 1724.
Credit: Rooyakkers et al
Still, the researchers couldn't determine exactly how the magma pool formed or has behaved since then, nor could they determine the size of the pool. That's mostly because modern magma-detecting instruments, such as seismic tomography, can't accurately identify magma pools smaller than about 1 cubic kilometer.
How could these relatively small magma pools pose major threats? One reason centers on composition. For example, the drillers involved in the Krafla incident struck rhyolitic magma, which is more explosive than basalt, the type of magma that dominates the Krafla caldera.
As basalt ascends toward the surface, it could potentially combine with and "mobilize" the rhyolitic magma, causing a violent eruption that offers "little warning," the researchers wrote.
"So the concern in this case would be that you have a shallow rhyolitic magma that you don't know about, so it hasn't been considered in hazards planning," study author Shane Rooyakkers said in a press release published by The Geological Society of America. "If it's hit by new magma moving up, you might have a much more explosive eruption than you were anticipating."
To better understand and forecast such eruptions, the researchers called for improving magma-detection strategies, such as using extremely dense geophone arrays, which use soundwaves to monitor the earth for seismic events.
If magma-detection technology improves, scientists might someday be able to install sensors around previously hidden magma pools, which could provide warnings of upcoming eruptions. But for now, volcanologists still have much to learn about hidden magma pools, and their prevalence around the globe.
A newly discovered flying dinosaur nicknamed "Monkeydactyl" is the oldest known creature that evolved opposable thumbs, according to new research published in Current Biology.
The 160-million-year-old reptile is officially named Kunpengopterus antipollicatus. Discovered in China, the dinosaur was a darwinopteran pterosaur, a subgroup of pterosaurs, which first appeared 215 million years ago during the Triassic Period. Pterosaurs, like the pterodactyl, were the first vertebrates to evolve the ability of powered flight.
But unlike other pterosaurs, the Monkeydactyl was the only species in its group known to have opposable thumbs. It's a rare adaptation for non-mammals: The only extant examples are chameleons and some species of tree frogs. (Most birds have at least one opposable digit, though that digit is usually classified as a hallux, not a pollex, which means "thumb" in Latin.)
To analyze the anatomy of K. antipollicatus, an international team of researchers used microcomputed tomography scanning, which generates images of the inside of the body.
"The fingers of 'Monkeydactyl' are tiny and partly embedded in the slab," study co-author Fion Waisum Ma said in a press release. "Thanks to micro-CT scanning, we could see through the rocks, create digital models, and tell how the opposed thumb articulates with the other finger bones."
"This is an interesting discovery. It provides the earliest evidence of a true opposed thumb, and it is from a pterosaur — which wasn't known for having an opposed thumb."
As a tree-dwelling reptile, the Monkeydactyl probably evolved opposable thumbs so it could grasp tree branches, which would have helped it hang, avoid falls, and obtain food. This arboreal (tree-dwelling) locomotion would help the Monkeydactyl adapt to its home ecosystem, the subtropical forests of the Tiaojishan Formation in China during the Jurassic Period.
The researchers noted that the forests of the Tiaojishan Formation were likely warm and humid, thriving with "a rich and complex" diversity of tree-dwelling animals. But while the forests were home to multiple pterosaur species, the Monkeydactyl was likely the only one that was arboreal, spending most of its time in the treetops, while other pterosaurs occupied different levels of the forest.
K. antipollicatus and its phylogenetic position. (A and B) Holotype specimen BPMC 0042 (A) and a schematic skeletal drawing (B). Scale bars, 50 mm.Credit: Zhou et al.
This process — in which competing species manage to coexist by using the environment in different ways — is called "niche partitioning."
"Tiaojishan palaeoforest is home to many organisms, including three genera of darwinopteran pterosaurs," study author Xuanyu Zhou said in the press release. "Our results show that K. antipollicatus has occupied a different niche from Darwinopterus and Wukongopterus, which has likely minimized competition among these pterosaurs."
In general, pterosaurs are a prime example of how animals can evolve remarkably specialized adaptations. As pioneers of vertebrate flight, pterosaurs had strong and lightweight skeletons that ranged widely in size, with some boasting wingspans of more than 30 feet. The largest pterosaurs weighed more than 650 pounds and had jaws twice the length of Tyrannosaurus rex.
Unlike birds, which jump into the air using only their hind limbs, pterosaurs used their exceptionally strong hind limbs and forelimbs to push off the ground and gain enough launch power for flight. That these massive dinosaurs managed to fly, and did so successfully for about 80 million years, has long fascinated and puzzled scientists.
The recent discovery shows that pterosaurs developed even more remarkable adaptations than previously thought, suggesting there's still more to learn about the "monsters of the Mesozoic skies."How can modern technology help warn us of impending volcanic eruptions?
One promising answer may lie in satellite imagery. In a recent study published in Nature Geoscience, researchers used infrared data collected by NASA satellites to study the conditions near volcanoes in the months and years before they erupted.
The results revealed a pattern: Prior to eruptions, an unusually large amount of heat had been escaping through soil near volcanoes. This diffusion of subterranean heat — which is a byproduct of "large-scale thermal unrest" — could potentially represent a warning sign of future eruptions.
Conceptual model of large-scale thermal unrestCredit: Girona et al.
For the study, the researchers conducted a statistical analysis of changes in surface temperature near volcanoes, using data collected over 16.5 years by NASA's Terra and Aqua satellites. The results showed that eruptions tended to occur around the time when surface temperatures near the volcanoes peaked.
Eruptions were preceded by "subtle but significant long-term (years), large-scale (tens of square kilometres) increases in their radiant heat flux (up to ~1 °C in median radiant temperature)," the researchers wrote. After eruptions, surface temperatures reliably decreased, though the cool-down period took longer for bigger eruptions.
"Volcanoes can experience thermal unrest for several years before eruption," the researchers wrote. "This thermal unrest is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices, can be an early indicator of volcanic reactivation, can increase prior to different types of eruption and can be tracked through a statistical analysis of little-processed (that is, radiance or radiant temperature) satellite-based remote sensing data with high temporal resolution."
Temporal variations of target volcanoesCredit: Girona et al.
Although using satellites to monitor thermal unrest wouldn't enable scientists to make hyper-specific eruption predictions (like predicting the exact day), it could significantly improve prediction efforts. Seismologists and volcanologists currently use a range of techniques to forecast eruptions, including monitoring for gas emissions, ground deformation, and changes to nearby water channels, to name a few.
Still, none of these techniques have proven completely reliable, both because of the science and the practical barriers (e.g. funding) standing in the way of large-scale monitoring. In 2014, for example, Japan's Mount Ontake suddenly erupted, killing 63 people. It was the nation's deadliest eruption in nearly a century.
In the study, the researchers found that surface temperatures near Mount Ontake had been increasing in the two years prior to the eruption. To date, no other monitoring method has detected "well-defined" warning signs for the 2014 disaster, the researchers noted.
The researchers hope satellite-based infrared monitoring techniques, combined with existing methods, can improve prediction efforts for volcanic eruptions. Volcanic eruptions have killed about 2,000 people since 2000.
"Our findings can open new horizons to better constrain magma–hydrothermal interaction processes, especially when integrated with other datasets, allowing us to explore the thermal budget of volcanoes and anticipate eruptions that are very difficult to forecast through other geophysical/geochemical methods."
About 66 million years ago, a massive asteroid slammed into present-day Chicxulub, Mexico, triggering the extinction of dinosaurs. Scientists estimate the impact killed 75 percent of life on Earth. But what's remained more mysterious is how the event shaped the future of plant life, specifically tropical rainforests.
A new study published in Science explores how the so-called bolide impact at the end of the Cretaceous period paved the way for the evolution of our modern rainforests, the most diverse terrestrial ecosystems on Earth.
For the study, researchers analyzed thousands of samples of fossil pollen, leaves, and spores collected from various sites across Colombia. The researchers analyzed the samples to determine which types of plants were dominant, the diversity of plant life, and how insects interacted with plants.
All samples dated back to the Cretaceous-Paleogene boundary, some 70 million to 56 million years ago. Back then, the region's climate was mostly humid and hot, as it is today. However, the composition and structure of forests were quite different before the impact, according to the study results.
Tropical jungle with river and sun beam and foggy in the gardenSASITHORN via Adobe Stock
For one, the region's rainforests used to have a roughly equal mix of angiosperms (shrubs and flowering trees) and plants like conifers and ferns. The rainforests also had a more open canopy structure, which allowed more light to reach the forest floor and meant that plants faced less competition for light.
What changed after the asteroid hit? The results suggest the impact and its aftermath led to a 45 percent decrease in plant diversity, a loss from which the region took about 6 million years to recover. But different plants came to replace the old ones, with an increasing proportion of flowering plants sprouting up over the millennia.
"A single historical accident changed the ecological and evolutionary trajectory of tropical rainforests," Carlos Jaramillo, study author and paleopalynologist at the Smithsonian Tropical Research Institute in Panama City, told Science News. "The forests that we have today are really the by-product of what happened 66 million years ago."
Today's rainforests are significantly more biodiverse than they were 66 million years ago. One potential reason is that the more densely packed canopy structure of the post-impact era increased competition among plants, "leading to the vertical complexity seen in modern rainforests," the researchers wrote.
The extinction of long-necked, leaf-eating dinosaurs probably helped maintain this closed-canopy structure. Also boosting biodiversity was ash from the impact, which effectively fertilized the soil by adding more phosphorus. This likely benefited flowering plants over the conifers and ferns of the pre-impact era.
In addition to unraveling some of the mysteries about the origins of South America's lush biodiversity, the findings highlight how, even though life finds a way to recover from catastrophe, it can take a long time.
Lighting strikes in the Arctic may increase by approximately 100 percent by the end of the 21st century, according to a new study published in Nature Climate Change. If that happens, places like Alaska could suffer significantly higher rates of wildfires and permafrost loss, both of which could accelerate warming in the Arctic.
Some evidence suggests these changes are already underway. In 2015, Alaska suffered the second-most wildfires on record, burning more than 5.1 million acres across the state's northern region. Although it's difficult to measure, lightning likely started many of these fires.
Still, lightning is relatively rare in the Arctic. That's because lightning occurs when warm, moist air rises to meet cold air, which builds up electrical charge. When that charge exceeds a certain threshold, lightning strikes. Because places like Alaska have relatively cold, dry air, thunderstorms only form occasionally.
But climate change may be changing that. In 2019, the National Weather Service's office in Fairbanks, Alaska, reported an unusually high number of lightning strikes within 300 miles of the North Pole. The uptick in lighting may be no surprise, considering the Arctic is warming by more than twice the global average.
In the recent study, researchers used satellite observations and climate data to explore how increasingly frequent lightning could transform the Arctic through changes like increased wildfires and permafrost loss.
"We projected how lightning in high-latitude boreal forests and Arctic tundra regions will change across North America and Eurasia," Yang Chen, study author and research scientist in the UCI Department of Earth System Science, said in a press release. "The size of the lightning response surprised us because expected changes at mid-latitudes are much smaller."
What's especially concerning about the uptick in Arctic lightning is that it could start a "lightning-fire-vegetation feedback loop."
The researchers explained how more lightning could cause more wildfires, which would burn away many of the shrubs, mosses, and other low-lying plants covering the Arctic terrain. Without those plants covering the ground, soil temperatures would rise, making it easier for deciduous trees to grow.
That might sound like a good thing. But expanding forests could also cause regional temperatures to rise because they would absorb more sunlight than the reflective, snow-covered Arctic terrain currently does. What's more, wildfires would melt Arctic permafrost, which stores massive amounts of organic carbon.
The end result of the lightning-fire-vegetation feedback loop would be the release of carbon into the atmosphere.
Forest-fire helicopters in actionCredit: Karsten via Adobe Stock
Still, the variability in climate modeling and lightning monitoring makes it difficult to predict future changes with a high degree of accuracy.
"This phenomenon is very sporadic, and it's very difficult to measure accurately over long time periods," James T. Randerson, study co-author and professor in the Department of Earth System Science at the University of California, Irvine, said in the press release. "It's so rare to have lightning above the Arctic Circle."
The researchers concluded the study by calling for more high-quality lightning monitoring systems, based on the ground and in space.
"Given the large amount of permafrost soil carbon stored in northern ecosystems, this analysis highlights the importance of improving lightning monitoring in the Arctic and the need to develop better models of lightning, fire dynamics, and feedback with vegetation and soils," they wrote.
