Researchers unveil mysteries of ancient Earth

A team of researchers has made strides in understanding the formation of massif-type anorthosites, enigmatic rocks that only formed during the middle part of Earth's history. These plagioclase-rich igneous rock formations, which can cover areas as large as 42,000 square kilometers and host titanium ore deposits, have puzzled scientists for decades due to conflicting theories about their origins.

A new study published in Science Advances on Aug. 14 highlights the intricate connections between Earth's evolving mantle and crust and the tectonic forces that have shaped the planet throughout its history. It also provides new ways to explore when plate tectonics began, how subduction dynamics operated billions of years ago and the evolution of Earth's crust.

The research team, led by Rice's Duncan Keller and Cin-Ty Lee, studied massif-type anorthosites to test ideas about the magmas that formed them. The research focused on the Marcy and Morin anorthosites, classic examples from North America's Grenville orogen that are about 1.1 billion years old.

By analyzing the isotopes of boron, oxygen, neodymium and strontium in the rocks as well as conducting petrogenetic modeling, the researchers discovered that the magmas that formed these anorthosites were rich in melts derived from oceanic crust altered by seawater at low temperatures. They also found isotopic signatures corresponding to other subduction zone rocks such as abyssal serpentinite.

"Our research indicates that these giant anorthosites likely originated from the extensive melting of subducted oceanic crust beneath convergent continental margins," said Keller, the Clever Planets Postdoctoral Research Associate, Earth, Environmental and Planetary Sciences and the study's lead author. "Because the mantle was hotter in the past, this process directly connects the formation of massif-type anorthosites to Earth's thermal and tectonic evolution."

The study, which combines classical methods with the novel application of boron isotopic analysis to massif-type anorthosites, suggests that these rocks formed during very hot subduction that may have been prevalent billions of years ago.

Because massif-type anorthosites don't form on Earth today, the new evidence linking these rocks to very hot subduction on the early Earth opens new interdisciplinary approaches for understanding how these rocks chronicle the physical evolution of our planet.

"This research advances our understanding of ancient rock formations and sheds light on the broader implications for Earth's tectonic and thermal history," said Lee, the Harry Carothers Wiess Professor of Geology, professor of Earth, environmental and planetary sciences and study co-author.

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Rocks from Mars' Jezero Crater, which likely predate life on Earth, contain signs of water

In a new study appearing today in the journal AGU Advances, scientists at MIT and NASA report that seven rock samples collected along the "fan front" of Mars' Jezero Crater contain minerals that are typically formed in water. The findings suggest that the rocks were originally deposited by water, or may have formed in the presence of water.

The seven samples were collected by NASA's Perseverance rover in 2022 during its exploration of the crater's western slope, where some rocks were hypothesized to have formed in what is now a dried-up ancient lake. Members of the Perseverance science team, including MIT scientists, have studied the rover's images and chemical analyses of the samples, and confirmed that the rocks indeed contain signs of water, and that the crater was likely once a watery, habitable environment.

Whether the crater was actually inhabited is yet unknown. The team found that the presence of organic matter -- the starting material for life -- cannot be confirmed, at least based on the rover's measurements. But judging from the rocks' mineral content, scientists believe the samples are their best chance of finding signs of ancient Martian life once the rocks are returned to Earth for more detailed analysis.

"These rocks confirm the presence, at least temporarily, of habitable environments on Mars," says the study's lead author, Tanja Bosak, professor of geobiology in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). "What we've found is that indeed there was a lot of water activity. For how long, we don't know, but certainly for long enough to create these big sedimentary deposits."

What's more, some of the collected samples may have originally been deposited in the ancient lake more than 3.5 billion years ago -- before even the first signs of life on Earth.

"These are the oldest rocks that may have been deposited by water, that we've ever laid hands or rover arms on," says co-author Benjamin Weiss, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. "That's exciting, because it means these are the most promising rocks that may have preserved fossils, and signatures of life."

The study's MIT co-authors include postdoc Eva Scheller, and research scientist Elias Mansbach, along with members of the Perseverance science team.

At the front

The new rock samples were collected in 2022 as part of the rover's Fan Front Campaign -- an exploratory phase during which Perseverance traversed Jezero Crater's western slope, where a fan-like region contains sedimentary, layered rocks. Scientists suspect that this "fan front" is an ancient delta that was created by sediment that flowed with a river and settled into a now bone-dry lakebed. If life existed on Mars, scientists believe that it could be preserved in the layers of sediment along the fan front.

In the end, Perseverance collected seven samples from various locations along the fan front. The rover obtained each sample by drilling into the Martian bedrock and extracting a pencil-sized core, which it then sealed in a tube to one day be retrieved and returned to Earth for detailed analysis.

Prior to extracting the cores, the rover took images of the surrounding sediments at each of the seven locations. The science team then processed the imaging data to estimate a sediment's average grain size and mineral composition. This analysis showed that all seven collected samples likely contain signs of water, suggesting that they were initially deposited by water.

Specifically, Bosak and her colleagues found evidence of certain minerals in the sediments that are known to precipitate out of water.

"We found lots of minerals like carbonates, which are what make reefs on Earth," Bosak says. "And it's really an ideal material that can preserve fossils of microbial life."

Interestingly, the researchers also identified sulfates in some samples that were collected at the base of the fan front. Sulfates are minerals that form in very salty water -- another sign that water was present in the crater at one time -- though very salty water, Bosak notes, "is not necessarily the best thing for life." If the entire crater was once filled with very salty water, then it would be difficult for any form of life to thrive. But if only the bottom of the lake were briny, that could be an advantage, at least for preserving any signs of life that may have lived further up, in less salty layers, that eventually died and drifted down to the bottom.

"However salty it was, if there were any organics present, it's like pickling something in salt," Bosak says. "If there was life that fell into the salty layer, it would be very well-preserved."

Fuzzy fingerprints

But the team emphasizes that organic matter has not been confidently detected by the rover's instruments. Organic matter can be signs of life, but can also be produced by certain geological processes that have nothing to do with living matter. Perseverance's predecessor, the Curiosity rover, had detected organic matter throughout Mars' Gale Crater, which scientists suspect may have come from asteroids that made impact with Mars in the past.

And in a previous campaign, Perseverance detected what appeared to be organic molecules at multiple locations along Jezero Crater's floor. These observations were taken by the rover's Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument, which uses ultraviolet light to scan the Martian surface. If organics are present, they can glow, similar to material under a blacklight. The wavelengths at which the material glows act as a sort of fingerprint for the kind of organic molecules that are present.

In Perseverance's previous exploration of the crater floor, SHERLOC appeared to pick up signs of organic molecules throughout the region, and later, at some locations along the fan front. But a careful analysis, led by MIT's Eva Scheller, has found that while the particular wavelengths observed could be signs of organic matter, they could just as well be signatures of substances that have nothing to do with organic matter.

"It turns out that cerium metals incorporated in minerals actually produce very similar signals as the organic matter," Scheller says. "When investigated, the potential organic signals were strongly correlated with phosphate minerals, which always contain some cerium."

Scheller's work shows that the rover's measurements cannot be interpreted definitively as organic matter.

"This is not bad news," Bosak says. "It just tells us there is not very abundant organic matter. It's still possible that it's there. It's just below the rover's detection limit."

When the collected samples are finally sent back to Earth, Bosak says laboratory instruments will have more than enough sensitivity to detect any organic matter that might lie within.

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Record-breaking recovery of rocks that originated in Earth's mantle could reveal secrets of planet's history

Scientists have recovered the first long section of rocks that originated in the Earth's mantle, the layer below the crust and the planet's largest component.

The rocks will help unravel the mantle's role in the origins of life on Earth, the volcanic activity generated when it melts, and how it drives the global cycles of important elements such as carbon and hydrogen, according to the team.

The nearly continuous 1,268 metres of mantle rock was recovered from a "tectonic window," a section of the seabed where rocks from the mantle were exposed along the Mid-Atlantic Ridge, during Expedition 399 "Building Blocks of Life, Atlantis Massif" of the ocean drilling vessel JOIDES Resolution in Spring 2023.

With attempts dating back to the early 1960s, the recovery was a record-breaking achievement led by the International Ocean Discovery Program, an international marine research consortium of more than 20 countries that retrieves cores -- cylindrical samples of sediment and rock -- from the ocean floor to study Earth's history.

Since then, the expedition team has been compiling an inventory of the recovered mantle rocks to understand their composition, structure and context.

Their findings, presented in the journal Science, reveal a more extensive history of melting in the recovered rocks than expected.

Lead author Professor Johan Lissenberg from Cardiff University's School of Earth and Environmental Sciences, said: "When we recovered the rocks last year, it was a major achievement in the history of the Earth sciences, but, more than that, its value is in what the cores of mantle rocks could tell us about the makeup and evolution of our planet.

"Our study begins to look at the composition of the mantle by documenting the mineralogy of the recovered rocks, as well as their chemical makeup.

"Our results differ from what we expected. There is a lot less of the mineral pyroxene in the rocks, and the rocks have got very high concentrations of magnesium, both of which results from much higher amounts of melting than what we would have predicted."

This melting occurred as the mantle rose from the deeper parts of the Earth towards the surface.

Results from further analysis of this process could have major implications for the understanding of how magma is formed and leads to volcanism, the researchers claim.

"We also found channels through which melt was transported through the mantle, and so we are able to track the fate of magma after it is formed and travels upwards to the Earth's surface.

"This is important because it tells us how the mantle melts and feeds volcanoes, particularly those on the ocean floor that account for the majority of volcanism on Earth. Having access to these mantle rocks will allow us to make the connection between the volcanoes and the ultimate source of their magmas."

The study also provides initial results on how olivine, an abundant mineral in mantle rocks, reacts with seawater, leading to a series of chemical reactions that produce hydrogen and other molecules that can fuel life.

Scientists believe this might have been one of the underpinning processes in the origin of life on Earth.

Dr Susan Q Lang, an associate scientist in Geology and Geophysics at the Woods Hole Oceanographic Institution, who was a co-chief scientist on the expedition and part of a team continuing to analyse rock and fluid samples, said: "The rocks that were present on early Earth bear a closer resemblance to those we retrieved during this expedition than the more common rocks that make up our continents today.

"Analysing them gives us a critical view into the chemical and physical environments that would have been present early in Earth's history, and that could have provided a consistent source of fuel and favorable conditions over geologically long timeframes to have hosted the earliest forms of life."

The international team of more than 30 scientists from the JOIDES Resolution expedition will continue their research on the recovered drill cores to address a wide range of problems.

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High resolution techniques reveal clues in 3.5 billion-year-old biomass

To learn about the first organisms on our planet, researchers have to analyse the rocks of the early Earth. These can only be found in a few places on the surface of the Earth. The Pilbara Craton in Western Australia is one of these rare sites: there are rocks there that are around 3.5 billion years old containing traces of the microorganisms that lived at that time. A research team led by the University of Göttingen has now found new clues about the formation and composition of this ancient biomass, providing insights into the earliest ecosystems on Earth. The results were published in the journal Precambrian Research.

Using high-resolution techniques such as nuclear magnetic resonance spectroscopy (NMR) and near-edge X-ray Absorption Fine Structure (NEXAFS), the researchers analysed carbonaceous particles found rocks made of barium sulphate.

This enabled scientists to obtain important information about the structure of microscopically small particles and show that they are of biological origin.

It is likely that the particles were deposited as sediment in the body of water of a "caldera" -- a large cauldron-shaped hollow that forms after volcanic activity.

In addition, some of the particles must have been transported and changed by hydrothermal waters just beneath the surface of the volcano.

This indicates a turbulent history of sediment deposits. By analysing various carbon isotopes, the researchers concluded that different types of microorganisms were already living in the vicinity of the volcanic activity, similar to those found today at Icelandic geysers or at hot springs in Yellowstone National Park.

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Source rocks of the first real continents

Geoscientists have uncovered a missing link in the enigmatic story of how the continents developed -- a revised origin story that doesn't require the start of plate tectonics or any external factor to explain their formation. Instead, the findings published last week in Nature Communications, rely solely on internal geological forces that occurred within oceanic plateaus that formed during the first few hundred million years of Earth's history.

A major hurdle in understanding how the continents formed during the Archean Eon (four to 2.5 billion years ago) has been identifying the building blocks of Earth's early crust.

Much of the "new" Archean crust formed during this period comprised a very distinct association of three types of granitoid rocks -- tonalite, trondhjemite and granodiorite (TTG).

Understanding what went into making TTGs and the magmas they formed from has been difficult, because so many geological processes occurred between their initial melting and ultimate crystallization.

Earlier researchers focused on the trace element composition of these rocks, hoping to find clues about TTG magmas and their source.

"We tracked a specific set of trace elements that aren't affected by alteration and pristinely preserve signatures from the original magma that made new TTG crust," said Dr. Matthijs Smit, associate professor and Canada Research Chair at the University of British Columbia's (UBC) Department of Earth, Ocean and Atmospheric Sciences.

"These elements allowed us to look back through the chemical changes that TTG magmas go through and trace the melt compositions back to their initial state and source -- most likely a sort of gabbro."

"Funnily enough, many people have varieties of this type of rock as a kitchen countertop," Dr. Smit says.

"In a way, many people are preparing their dinner on the type of rock that was responsible for making our modern continents."

The Archean TTG crust is still part of the continents today.

For instance, in North America they make up much of the Canadian Interior between the Cordillera mountain belt in the west and the Grenville and Appalachian mountain belts in the east.

The majority of Ontario, Quebec, Manitoba, Saskatchewan, Northwest Territories and Nunavut is made up of Archean crustal fragments that are dominated by TTGs and their slightly younger and more evolved granite counterparts.

"All of these rocks -- and especially their combination -- can be explained by the model we present," said Dr. Smit.

"Ours is a simple model in which TTGs, as well as the younger rocks that TTGs are typically associated with, resulted from the slow burial, thickening and melting of precursor crust that likely resembled oceanic plateaus. The continental crust was destined to develop the way it did, because it kept getting buried further and the rocks at its base had no choice but to melt. In doing so, they made the TTGs that proved a winning recipe for continental survival and growth."

The UBC researchers' discovery of a stand-alone "intra-crustal" mechanism to make TTGs dispels the long-standing theory that Archean TTGs are formed in Earth's first subduction zones and mark the start of plate tectonics.

"There's always been a 'chicken-and-egg' question of which came first -- the start of plate tectonics or TTG magmatism to make new continental crust," says Dr. Smit.

"We show that these things may actually not be directly related. The recognition of the type of source rock makes this leap possible and also takes away the need to have other mechanisms, such as meteorite impact, explain the growth of the first real continents."

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Moon rocks with unique dust found

Our Earth's Moon is almost completely covered in dust. Unlike on Earth, this dust is not smoothed by wind and weather, but is sharp-edged and also electrostatically charged. This dust has been studied since the Apollo era at the end of the 1960s. Now, an international research team led by Dr. Ottaviano Rüsch from the University of Münster has for the first time discovered anomalous meter-sized rocks on the lunar surface that are covered in dust and presumably exhibit unique properties -- such as magnetic anomalies. The scientists' most important finding is that only very few boulders on the Moon have a layer of dust with very special reflective properties. For example, the dust on these newly discovered boulders reflects sunlight differently than on previously known rocks. These new findings help scientists to understand the processes that form and change the lunar crust. The results of the study have been published in the Journal of Geophysical Research -- Planets.

It is known that there are magnetic anomalies on the lunar surface, particularly near a region called Reiner Gamma.

However, the question of whether rocks can be magnetic has never been investigated.

"Current knowledge of the Moon's magnetic properties is very limited, so these new rocks will shed light on the history of the Moon and its magnetic core," says Ottaviano Rüsch from the 'Institut für Planetologie', categorizing the discovery.

"For the first time, we have investigated the interactions of dust with rocks in the Reiner Gamma region -- more precisely, the variations in the reflective properties of these rocks. For example, we can deduce to what extent and in which direction the sunlight is reflected by these large rocks." The images were taken by NASA's Lunar Reconnaissance Orbiter spacecraft, which orbits the Moon.

The research team was originally interested in cracked rocks.

They first used artificial intelligence to search through around one million images for fractured rocks -- these images were also taken by the Lunar Reconnaissance Orbiter.

"Modern data processing methods allow us to gain completely new insights into global contexts -- at the same time, we keep finding unknown objects in this way, such as the anomalous rocks that we are investigating in this new study," says Valentin Bickel from the Center for Space and Habitability at the University of Bern.

The search algorithm identified around 130,000 interesting rocks, half of which were scrutinized by the scientists.

"We recognized a boulder with distinctive dark areas on just one image. This rock was very different from all the others, as it scatters less light back towards the sun than other rocks. We suspect that this is due to the particular dust structure, such as the density and grain size of the dust," Ottaviano Rüsch explains.

"Normally, lunar dust is very porous and reflects a lot of light back in the direction of illumination. However, when the dust is compacted, the overall brightness usually increases. This is not the case with the observed dust-covered rocks," adds Marcel Hess from TU Dortmund University.

This is a fascinating discovery -- however, the scientists are still in the early stages of understanding this dust and its interactions with the rock.

In the coming weeks and months, the scientists want to further investigate the processes that lead to the interactions between dust and rocks and to the formation of the special dust structure.

These processes include, for example, the lifting of the dust due to electrostatic charging or the interaction of the solar wind with local magnetic fields.

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Paleolithic humans may have understood the properties of rocks for making stone tools

A research group led by the Nagoya University Museum and Graduate School of Environmental Studies in Japan has clarified differences in the physical characteristics of rocks used by early humans during the Paleolithic. They found that humans selected rock for a variety of reasons and not just because of how easy it was to break off. This suggests that early humans had the technical skill to discern the best rock for the tool. The researchers published the results in the Journal of Paleolithic Archaeology.

As Homo sapiens moved from Africa to Eurasia, they used stone tools made of rocks, such as obsidian and flint, to cut, slice, and craft ranged weapons.

Because of the significant role they played in their culture, understanding how early humans made stone tools is important to archaeologists.

Since the geographic expansion of Homo sapiens in Eurasia started in the Middle East, archaeologists Eiki Suga and Seiji Kadowaki from Nagoya University focused on the prehistoric sites belonging to three chronological periods in the Jebel Qalkha area, southern Jordan.

The team analyzed flint nodules in the outcrops that were exploited during the Middle and Upper Paleolithic (70,000 to 30,000 years ago).

They believe Paleolithic humans understood which rocks were appropriate for making tools and, therefore, intentionally searched for them.

According to their hypothesis, Paleolithic humans intentionally searched for flint that was translucent and smooth, as it could be easily broken off the rock face and shaped into sharp edges.

The group used a Schmidt Hammer and a Rockwell Hardness Device to test the mechanical properties of the rocks.

The Schmidt Hammer measures the elastic behavior of a material after the hammer strikes it, which tells researchers its rebound hardness.

The Rockwell hardness device presses a diamond indenter on the rock surface to test its strength.

At first, as Suga and Kadowaki expected, fine-grained flint was found to require less force to fracture than medium-grained flint.

This would have made the fine-grained flint more attractive in producing small stone tools.

Indeed, many stone tools from the Early Upper Paleolithic (40,000 to 30,000 years ago) contain fine-grained flint.

However, an earlier study by the same team found that during the Late Middle Paleolithic and the Initial Upper Paleolithic (70,000 to 40,000 years ago), medium-grained flint was more commonly used in stone tools than fine-grained flint.

But if fine-grained flint was so easy to use, why did our ancestors not make all their tools from it?

On further investigation, the researchers found that much of the fine-grained flint in the area suffered from abundant internal fractures caused by geological activities, which would have made it unsuitable for large stone tools, such as Levallois products and robust blades.

Therefore, it seems that Paleolithic humans selected the medium-grained flint for large tools, even though it was a tough material to modify into tools, as it was more likely to last longer.

This offers a fascinating insight into our ancestors' behavior, as they selected flint based on many factors other than just how easy it was to fracture and could discern the most suitable rock to use to make stone tools.

Suga is enthusiastic about the findings, which suggest the complexity of our ancestors' behaviour.

"This study illustrates that the Paleolithic humans changed their choice of raw material to suit their stone tool morphologies and production techniques," he said.

"We believe that these prehistoric humans had a sensory understanding of the characteristics of the rocks and intentionally selected the stone material to be used according to the form and production technique of the desired stone tools. This intentional selection of the lithic raw material may have been an important component of the production of stone tools. This may show some aspect of flexible technological behavior adapted to the situation."

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Alpine rock reveals dynamics of plate movements in Earth's interior

Examining how plates move in Earth's mantle and how mountains form is no easy feat. Certain rocks that have sunk deep into Earth's interior and then returned from there can deliver answers.

Geoscientists analyze rocks in mountain belts to reconstruct how they once moved downwards into the depths and then returned to the surface. This history of burial and exhumation sheds light on the mechanisms of plate tectonics and mountain building. Certain rocks that sink far down into Earth's interior together with plates are transformed into different types under the enormous pressure that prevails there. During this UHP metamorphosis (UHP: Ultra High Pressure), silica (SiO2) in the rock, for example, becomes coesite, which is also referred to as the UHP polymorph of SiO2. Although it is chemically still silica, the crystal lattices are more tightly packed and therefore denser. When the plates move upwards again from the depths, the UHP rocks also come to the surface and can be found in certain places in the mountains. Their mineral composition provides information about the pressures to which they were exposed during their vertical journey through Earth's interior. Using lithostatic pressure as a unit of measurement, it is possible to correlate pressure and depth: the higher the pressure, the deeper the rocks once lay.

Until now, research had assumed that UHP rocks were buried at a depth of 120 kilometers. From there, they returned to the surface together with the plates. In the process, ambient pressure decreased at a stable rate, i.e. statically. However, a new study by Goethe University Frankfurt and the universities of Heidelberg and Rennes (France) calls this assumption of a long, continuous ascent into question. Among those involved in the study on the part of Goethe University Frankfurt were first author Cindy Luisier, who came to the university on a Humboldt Research Fellowship, and Thibault Duretz, head of the Geodynamic Modeling Working Group at the Department of Geosciences. The research team analyzed whiteschist from the Dora Maira Massif in the Western Alps, Italy. "Whiteschists are rocks that formed as a result of the UHP metamorphosis of a hydrothermally altered granite during the formation of the Alps," explains Duretz. "What is special about them is the large amount of coesite. The coesite crystals in the whiteschist are several hundred micrometers in size, which makes them ideal for our experiments." The piece of whiteschist from the Dora Maira Massif contained pink garnets in a silvery-white matrix composed of quartz and other minerals. "The rock has special chemical and thus mineralogical properties," says Duretz. Together with the team, he analyzed it by first cutting a very thin slice about 50 micrometers thick and then gluing it onto glass. In this way, it was possible to identify the minerals under a microscope. The next step was computer modeling of specific, particularly interesting areas.

These areas were silica particles surrounded by the grains of pink garnet, in which two SiO2 polymorphs had formed. One of these was coesite, which had formed under very high pressure (4.3 gigapascals). The other silica polymorph was quartz, which lay like a ring around the coesite. It had formed under much lower pressure (1.1 gigapascals). The whiteschist had evidently first been exposed to very high and then much lower pressure. There had been a sharp decrease in pressure or decompression. The most important discovery was that spoke-shaped cracks radiated from the SiO2 inclusions in all directions: the result of the phase transition from coesite to quartz. The effect of this transition was a large change in volume, and it caused extensive geological stresses in the rock. These made the garnet surrounding the SiO2 inclusions fracture. "Such radial cracks can only form if the host mineral, the garnet, stays very strong," explains Duretz. "At such temperatures, garnet only stays very strong if the pressure drops very quickly." On a geological timescale, "very quickly" means in thousands to hundreds of thousands of years. In this "short" period, the pressure must have dropped from 4.3 to 1.1 gigapascals. The garnet would otherwise have creeped viscously to compensate for the change in volume in the SiO2 inclusions, instead of forming cracks.

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Ancient carbon in rocks releases as much carbon dioxide as the world's volcanoes

A new study led by the University of Oxford has overturned the view that natural rock weathering acts as a CO2 sink, indicating instead that this can also act as a large CO2 source, rivalling that of volcanoes. The results, published today in the journal Nature, have important implications for modelling climate change scenarios.

Rocks contain an enormous store of carbon in the ancient remains of plants and animals that lived millions of years ago. This means that the "geological carbon cycle" acts as a thermostat that helps to regulate the Earth's temperature. For instance, during chemical weathering rocks can suck up CO2 when certain minerals are attacked by the weak acid found in rainwater. This process helps to counteract the continuous CO2 released by volcanoes around the world, and forms part of Earth's natural carbon cycle that has helped keep the surface habitable to life for a billion years or more.

However, for the first time this new study measured an additional natural process of CO2 release from rocks to the atmosphere, finding that it is as significant as the CO2 released from volcanoes around the world. Currently, this process is not included in most models of the natural carbon cycle.

The process occurs when rocks that formed on ancient seafloors (where plants and animals were buried in sediments) are pushed back up to Earth's surface, for example when mountains like the Himalayas or Andes form. This exposes the organic carbon in the rocks to oxygen in the air and water, which can react and release CO2. This means that weathering rocks could be a source of CO2, rather than the commonly assumed sink.

Up to now, measuring the release of this CO2 from weathering organic carbon in rocks has proved difficult. In the new study, the researchers used a tracer element (rhenium) which is released into water when rock organic carbon reacts with oxygen. Sampling river water to measure rhenium levels makes it possible to quantify CO2 release. However, sampling all river water in the world to get a global estimate would be a significant challenge.

To upscale over Earth's surface, the researchers did two things. First, they worked out how much organic carbon is present in rocks near the surface. Second, they worked out where these were being exposed most rapidly, by erosion in steep, mountain locations.

Dr Jesse Zondervan, the researcher who led the study at the Department of Earth Sciences, University of Oxford, said: "The challenge was then how to combine these global maps with the river data, while considering uncertainties. We fed all of our data into a supercomputer at Oxford, simulating the complex interplay of physical, chemical, and hydrological processes. By piecing together this vast planetary jigsaw, we could finally estimate the total carbon dioxide emitted as these rocks weather and exhale their ancient carbon into the air."

This could then be compared to how much CO2 could be drawn down by natural rock weathering of silicate minerals. The results identified many large areas where weathering was a CO2 source, challenging the current view about how weathering impacts the carbon cycle. Hotspots of CO2 release were concentrated in mountain ranges with high uplift rates that cause sedimentary rocks to be exposed, such as the eastern Himalayas, the Rocky Mountains, and the Andes. The global CO2 release from rock organic carbon weathering was found to be 68 megatons of carbon per year.

Professor Robert Hilton (Department of Earth Sciences, University of Oxford), who leads the ROC-CO2 research project that funded the study, said: "This is about 100 times less than present day human CO2 emissions by burning fossil fuels, but it is similar to how much CO2 is released by volcanoes around the world, meaning it is a key player in Earth's natural carbon cycle."

These fluxes could have changed during Earth's past. For instance, during periods of mountain building that bring up many rocks containing organic matter, the CO2 release may have been higher, influencing global climate in the past.

Ongoing and future work is looking into how changes in erosion due to human activities, alongside the increased warming of rocks due to anthropogenic climate changes, could increase this natural carbon leak. A question the team are now asking is if this natural CO2 release will increase over the coming century. "Currently we don't know -- our methods allow us to provide a robust global estimate, but not yet assess how it could change'' says Hilton.

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Enhanced chemical weathering: A solution to the climate crisis?

The Earth is getting hotter and consequences have been made manifest this summer around the world. Looking back in geological history, global warming events are not uncommon: Around 56 million years ago, during the period known as the Paleocene-Eocene Thermal Maximum (PETM), the temperatures rose by an average of 5 to 8 degrees Celsius. This development was most likely linked to increased volcanism and the associated release of masses of carbon dioxide into the atmosphere. The higher temperatures persisted for about 200,000 years. Back in 2021, Professor Philip Pogge von Strandmann of Johannes Gutenberg University Mainz (JGU) had already investigated the effect that eventually led to global cooling and climatic recovery after the PETM warming.

In short: Rainwater combined with the atmospheric carbon dioxide, resulting in carbonic acid that caused enhanced weathering of rock, thus releasing calcium and magnesium. Rivers then transported the calcium, magnesium, and carbonic acid into the oceans where the calcium, magnesium -- and also the carbon dioxide -- came together to form insoluble limestone. "In other words, there is a feedback effect that helps control the climate. High temperatures accelerate the chemical rock weathering process, reducing the levels of carbon dioxide in the atmosphere, allowing the climate to recover," said Pogge von Strandmann.

Climate required twice as long to regenerate 40 million years ago

Climate warming occurred again 16 million years after the PETM during the Middle Eocene Climatic Optimum or MECO. Although volcanic activity resulted in the discharge of roughly the same amounts of carbon dioxide into the atmosphere as during the PETM, it took far longer for the climate to restabilize. The warming effect lasted for an immense 400,000 years, twice as long as in the PETM. Why was recovery so slow during that period?

In searching for an answer, Pogge von Strandmann and co-authors, including first author Alex Krause, began analyzing 40-million-year-old oceanic carbonates and clay minerals to compare the results with those for similar 56-million-year-old examples. "Just as during the PETM, there was also intensified weathering and erosion in the MECO. However, there was far less exposed rock on the Earth's surface 40 million years ago. Instead, the Earth was extensively covered by a global rainforest the soil of which largely consisted of clay minerals," explained the researcher. In contrast with rock, clay does not weather; in fact, it is actually the product of weathering. "So despite the high temperatures, the widespread clay soil prevented rocks from being effectively weathered, a process known as soil shielding," the geoscientist pointed out.

Enhanced weathering for climate protection

How can we use this knowledge in today's world? "We study paleoclimates to determine whether and how we can positively influence our present climate. One option might be to boost the chemical weathering of rock. To help achieve this, we could plough finely crushed rock into our fields," said Pogge von Strandmann. The fine-grained particles of rock would erode rapidly, resulting in the binding of atmospheric carbon dioxide, thus enabling the climate to recuperate. Negative emissions technologies (NETs) such as this involving the absorption of carbon dioxide are the subjects of intense research across the globe. At the same time, however, if the weathering results in the formation of clay, the effects of the process would be significantly less efficient, as Pogge von Strandmann has discovered. Clay retains the calcium and magnesium that would otherwise be delivered to the ocean. The carbon dioxide would continue to flow into the oceans, but it would not be bound there and would be able to escape back into the atmosphere. In this case, the weathering effect would have next to no influence on the climate.

If the rock particles fully dissolve as a result of weathering, the enhanced weathering concept would turn out to be 100 percent efficient. However, if all the weathered materials were turned into clay, this would in its turn completely nullify the effect. In reality, the actual outcome would probably be somewhere between the two extremes: While there was enhanced erosion of rock in the PETM so that the climate normalized more rapidly, clay formation was predominant during the MECO. The extent to which the crushed rock dissolves and how much of it is preserved as clay depends on a range of local factors, such as the globally pre-existing levels of clay and rock. So in order to establish whether the process of enhanced weathering is a viable approach, it would first be necessary to find out how much clay is formed during the weathering process at each potential location.

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'Planting' rocks in farms, along with emissions reductions, could help meet key IPCC carbon removal goal

Farmers around the world could help the planet reach a key carbon removal goal set by the Intergovernmental Panel on Climate Change (IPCC) by mixing crushed volcanic rocks into their fields, a new study reports. The study also highlights wet, warm tropics as the most promising locations for this climate intervention strategy.

The study provides one of the first global estimates of the potential carbon dioxide drawdown from basalt application on agricultural fields worldwide. It was published in Earth's Future, AGU's journal for interdisciplinary research on the past, present and future of our planet and its inhabitants.

This type of climate intervention is called enhanced rock weathering. It takes advantage of the weathering process, which naturally sequesters carbon dioxide in carbonate minerals. The idea is simple: speed up weathering in a way that also benefits people. When used in parallel with emissions reductions, it can help slow the pace of climate change.

And it may be a safer bet than other carbon drawdown approaches, according to the study authors.

"Enhanced rock weathering poses fewer risks compared to other climate interventions," said S. Hun Baek, a climate scientist at Yale University who led the study. "It also provides some key benefits, like rejuvenating depleted soils and countering ocean acidification, that may make it more socially desirable."

The new study explores the potential of applying crushed basalt, a fast-weathering rock that forms as lava cools, to agricultural fields around the world and highlights which regions can most efficiently break down the rocks.

"There's tremendous potential here," said Noah Planavsky, a geochemist at Yale University who co-authored the study. "Although we still have things to learn from a basic science perspective, there is promise, and we need to focus on what we can do from market and finance perspectives."

A previous study used a separate method of calculating carbon dioxide removal to estimate carbon drawdown by the year 2050, but the researchers wanted to look beyond country borders and further into the future.

The researchers used a new biogeochemical model to simulate how applying crushed basalt to global croplands would draw down carbon dioxide, to test the sensitivity of enhanced rock weathering to climate and to pinpoint the areas where the method could be most effective.

The new model simulated enhanced rock weathering on 1,000 agricultural sites around the world under two emissions scenarios from 2006 to 2080. They found that in the 75-year study period, those agricultural sites would draw down 64 gigatons of carbon dioxide. Extrapolating that to all agricultural fields, representing the world's total potential application of this strategy, up to 217 gigatons of carbon could be sequestered in that time period.

"The latest IPCC report said we need to remove 100 to 1,000 gigatons of carbon by 2100 in addition to steeply reducing emissions to keep global temperature from rising more than one and a half degrees Celsius," said Baek. "Scaling up to global croplands, the estimates of carbon removal we found are roughly comparable to the lower end of that range needed to have a fighting chance of meeting those climate goals."

Because weathering progresses more quickly in hot and wet environments, enhanced rock weathering would work more quickly in tropical regions than higher latitudes, the study highlights. Farmers and companies looking to invest in carbon drawdown solutions make cost- and carbon-efficient choices by targeting basalt application in tropical fields.

The model revealed another promising result: Enhanced rock weathering works just as well, if not a little better, in warmer temperatures. Some other carbon drawdown approaches, such as those that rely on soil organic carbon storage, become less effective with continual warming.

"Enhanced rock weathering is surprisingly resilient to climate change," Baek said. "Our results show that it's relatively insensitive to climate change and works about the same under moderate and severe global warming scenarios. This gives us confidence in its potential as a long-term strategy."

Farmers already apply millions of tons of limestone (a calcium carbonate rock that can either be a carbon source or sink) to their fields to deliver nutrients and control soil acidity, so gradually changing the rock type could mean a smooth transition to implementing enhanced rock weathering at scale, Planavsky said.

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Earth formed from dry, rocky building blocks

Billions of years ago, in the giant disk of dust, gas, and rocky material that orbited our young sun, larger and larger bodies coalesced to eventually give rise to the planets, moons, and asteroids we see today. Scientists are still trying to understand the processes by which planets, including our home planet, were formed. One way researchers can study how Earth formed is to examine the magmas that flow up from deep within the planet's interior. The chemical signatures from these samples contain a record of the timing and the nature of the materials that came together to form Earth -- analogous to how fossils give us clues about Earth's biological past.

Now, a study from Caltech shows that the early Earth accreted from hot and dry materials, indicating that our planet's water -- the crucial component for the evolution of life -- must have arrived late in the history of Earth's formation.

The study, involving an international team of researchers, was conducted in the laboratories of Francois Tissot, assistant professor of geochemistry and Heritage Medical Research Institute Investigator; and Yigang Zhang of the University of Chinese Academy of Sciences. A paper describing the research appears in the journal Science Advances. Caltech graduate student Weiyi Liu is the paper's first author.

Though humans do not have a way to journey into the interior of our planet, the rocks deep within the earth can naturally make their way to the surface in the form of lavas. The parental magmas of these lavas can originate from different depths within Earth, such as the upper mantle, which begins around 15 kilometers under the surface and extends for about 680 kilometers; or the lower mantle, which spans from a depth of 680 kilometers all the way to the core-mantle boundary at about 2,900 kilometers below our feet. Like sampling different layers of a cake -- the frosting, the filling, the sponge -- scientists can study magmas originating from different depths to understand the different "flavors" of Earth's layers: the chemicals found within and their ratios with respect to one another.

Because the formation of Earth was not instantaneous and instead involved materials accreting over time, samples from the lower mantle and upper mantle give different clues to what was happening over time during Earth's accretion. In the new study, the team found that the early Earth was primarily composed of dry, rocky materials: chemical signatures from deep within the planet showed a lack of so-called volatiles, which are easily evaporated materials like water and iodine. In contrast, samples of the upper mantle revealed a higher proportion of volatiles, three times of those found in the lower mantle. Based on these chemical ratios, Liu created a model that showed Earth formed from hot, dry, rocky materials, and that a major addition of life-essential volatiles, including water, only occurred during the last 15 percent (or less) of Earth's formation.

The study is a crucial contribution to theories of planet formation, a field which has undergone several paradigm shifts in recent decades and is still characterized by vigorous scientific debate. In this context, the new study makes important predictions for the nature of the building blocks of other terrestrial planets -- Mercury and Venus -- which would be expected to have formed from similarly dry materials.

"Space exploration to the outer planets is really important because a water world is probably the best place to look for extraterrestrial life," Tissot says. "But the inner solar system shouldn't be forgotten. There hasn't been a mission that's touched Venus's surface for nearly 40 years, and there has never been a mission to the surface of Mercury. We need to be able to study those worlds to better understand how terrestrial planets such as Earth formed."

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Navigating underground with cosmic-ray muons

Superfast, subatomic-sized particles called muons have been used to wirelessly navigate underground in a reportedly world first. By using muon-detecting ground stations synchronized with an underground muon-detecting receiver, researchers at the University of Tokyo were able to calculate the receiver's position in the basement of a six-story building. As GPS cannot penetrate rock or water, this new technology could be used in future search and rescue efforts, to monitor undersea volcanoes, and guide autonomous vehicles underground and underwater.

GPS, the global positioning system, is a well-established navigation tool and offers an extensive list of positive applications, from safer air travel to real-time location mapping. However, it has some limitations. GPS signals are weaker at higher latitudes and can be jammed or spoofed (where a counterfeit signal replaces an authentic one). Signals can also be reflected off surfaces like walls, interfered with by trees, and can't pass through buildings, rock or water.

By comparison, muons have been making headlines in recent years for their abilityto help us look deep inside volcanoes, peek through pyramids and see inside cyclones. Muons fall constantly and frequently around the world (about 10,000 per square meter per minute) and can't be tampered with. "Cosmic-ray muons fall equally across the Earth and always travel at the same speed regardless of what matter they traverse, penetrating even kilometers of rock," explained Professor Hiroyuki Tanaka from Muographix at the University of Tokyo. "Now, by using muons, we have developed a new kind of GPS, which we have called the muometric positioning system (muPS), which works underground, indoors and underwater."

MuPS was initially created to help detect seafloor changes caused by underwater volcanoes or tectonic movement. It uses four muon-detecting reference stations aboveground to provide coordinates for a muon-detecting receiver underground. Early iterations of this technology required the receiver to be connected to a ground station by a wire, greatly restricting movement. However, this latest research uses high-precision quartz clocks to synchronize the ground stations with the receiver. The four parameters provided by the reference stations plus the synchronized clocks used to measure the muons' "time-of-flight" enables the receiver's coordinates to be determined. This new system is called the muometric wireless navigation system (MuWNS).

To test the navigation ability of MuWNS, reference detectors were placed on the sixth floor of a building while a "navigatee" took a receiver detector to the basement floor. They slowly walked up and down the corridors of the basement while holding the receiver. Rather than navigating in real time, measurements were taken and used to calculate their route and confirm the path they had taken.

"The current accuracy of MuWNS is between 2 meters and 25 meters, with a range of up to 100 meters, depending on the depth and speed of the person walking. This is as good as, if not better than, single-point GPS positioning aboveground in urban areas," said Tanaka. "But it is still far from a practical level. People need one-meter accuracy, and the key to this is the time synchronization."

Improving this system to enable real-time, meter-accurate navigation hinges on time and money. Ideally the team wants to use chip-scale atomic clocks (CSAC): "CSACs are already commercially available and are two orders of magnitude better than the quartz clocks we currently use. However, they are too expensive for us to use now. But, I foresee that they will become much cheaper as the global demand for CSAC for cellphones increases," said Tanaka.

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Iron-rich rocks unlock new insights into Earth's planetary history

Visually striking layers of burnt orange, yellow, silver, brown and blue-tinged black are characteristic of banded iron formations, sedimentary rocks that may have prompted some of the largest volcanic eruptions in Earth's history, according to new research from Rice University.

The rocks contain iron oxides that sank to the bottom of oceans long ago, forming dense layers that eventually turned to stone. The study published this week in Nature Geoscience suggests the iron-rich layers could connect ancient changes at Earth's surface -- like the emergence of photosynthetic life -- to planetary processes like volcanism and plate tectonics.

In addition to linking planetary processes that were generally thought to be unconnected, the study could reframe scientists' understanding of Earth's early history and provide insight into processes that could produce habitable exoplanets far from our solar system.

"These rocks tell -- quite literally -- the story of a changing planetary environment," said Duncan Keller, the study's lead author and a postdoctoral researcher in Rice's Department of Earth, Environmental and Planetary Sciences. "They embody a change in the atmospheric and ocean chemistry."

Banded iron formations are chemical sediments precipitated directly from ancient seawater rich in dissolved iron. Metabolic actions of microorganisms, including photosynthesis, are thought to have facilitated the precipitation of the minerals, which formed layer upon layer over time along with chert (microcrystalline silicon dioxide). The largest deposits formed as oxygen accumulated in Earth's atmosphere about 2.5 billion years ago.

"These rocks formed in the ancient oceans, and we know that those oceans were later closed up laterally by plate tectonic processes," Keller explained.

The mantle, though solid, flows like a fluid at about the rate that fingernails grow. Tectonic plates -- continent-sized sections of the crust and uppermost mantle -- are constantly on the move, largely as a result of thermal convection currents in the mantle. Earth's tectonic processes control the life cycles of oceans.

"Just like the Pacific Ocean is being closed today -- it's subducting under Japan and under South America -- ancient ocean basins were destroyed tectonically," he said. "These rocks either had to get pushed up onto continents and be preserved -- and we do see some preserved, that's where the ones we're looking at today come from -- or subducted into the mantle."

Because of their high iron content, banded iron formations are denser than the mantle, which made Keller wonder whether subducted chunks of the formations sank all the way down and settled in the lowest region of the mantle near the top of Earth's core. There, under immense temperature and pressure, they would have undergone profound changes as their minerals took on different structures.

"There's some very interesting work on the properties of iron oxides at those conditions," Keller said. "They can become highly thermally and electrically conductive. Some of them transfer heat as easily as metals do. So it's possible that, once in the lower mantle, these rocks would turn into extremely conductive lumps like hot plates."

Keller and his co-workers posit that regions enriched in subducted iron formations might aid the formation of mantle plumes, rising conduits of hot rock above thermal anomalies in the lower mantle that can produce enormous volcanoes like the ones that formed the Hawaiian Islands. "Underneath Hawaii, seismological data show us a hot conduit of upwelling mantle," Keller said. "Imagine a hot spot on your stove burner. As the water in your pot is boiling, you'll see more bubbles over a column of rising water in that area. Mantle plumes are sort of a giant version of that."

"We looked at the depositional ages of banded iron formations and the ages of large basaltic eruption events called large igneous provinces, and we found that there's a correlation," Keller said. "Many of the igneous events -- which were so massive that the 10 or 15 largest may have been enough to resurface the entire planet -- were preceded by banded iron formation deposition at intervals of roughly 241 million years, give or take 15 million. It's a strong correlation with a mechanism that makes sense."

The study showed that there was a plausible length of time for banded iron formations to first be drawn deep into the lower mantle and to then influence heat flow to drive a plume toward Earth's surface thousands of kilometers above.

In his effort to trace the journey of banded iron formations, Keller crossed disciplinary boundaries and ran into unexpected insights.

"If what's happening in the early oceans, after microorganisms chemically change surface environments, ultimately creates an enormous outpouring of lava somewhere else on Earth 250 million years later, that means these processes are related and 'talking' to each other," Keller said. "It also means it's possible for related processes to have length scales that are far greater than people expected. To be able to infer this, we've had to draw on data from many different fields across mineralogy, geochemistry, geophysics and sedimentology."

Keller hopes the study will spur further research. "I hope this motivates people in the different fields that it touches," he said. "I think it would be really cool if this got people talking to each other in renewed ways about how different parts of the Earth system are connected."

Keller is part of the CLEVER Planets: Cycles of Life-Essential Volatile Elements in Rocky Planets program, an interdisciplinary, multi-institutional group of scientists led by Rajdeep Dasgupta, Rice's W. Maurice Ewing Professor of Earth Systems Science in the Department of Earth, Environmental and Planetary Sciences.

"This is an extremely interdisciplinary collaboration that's looking at how volatile elements that are important for biology -- carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur -- behave in planets, at how planets acquire these elements and the role they play in potentially making planets habitable," Keller said.

"We're using Earth as the best example that we have, but we're trying to figure out what the presence or absence of one or some of these elements might mean for planets more generally," he added.

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Study reveals new clues about how 'Earth's thermostat' controls climate

Rocks, rain and carbon dioxide help control Earth's climate over thousands of years -- like a thermostat -- through a process called weathering. A new study led by Penn State scientists may improve our understanding of how this thermostat responds as temperatures change.

"Life has been on this planet for billions of years, so we know Earth's temperature has remained consistent enough for there to be liquid water and to support life," said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences at Penn State. "The idea is that silicate rock weathering is this thermostat, but no one has ever really agreed on its temperature sensitivity."

Because many factors go into weathering, it has been challenging to use results of laboratory experiments alone to create global estimates of how weathering responds to temperature changes, the scientists said.

The team combined laboratory measurements and soil analysis from 45 soil sites around the world and many watersheds to better understand weathering of the major rock types on Earth and used those findings to create a global estimate for how weathering responds to temperature.

"When you do experiments in the laboratory versus taking samples from soil or a river, you get different values," Brantley said. "So what we tried to do in this research is look across those different spatial scales and figure out how we can make sense of all this data geochemists around the world been accumulating about weathering on the planet. And this study is a model for how we can do that."

Weathering represents part of a balancing act of carbon dioxide in Earth's atmosphere. Volcanoes have emitted large amounts of carbon dioxide through Earth's history, but instead of turning the planet into a hot house, the greenhouse gas is slowly removed via weathering.

Rain takes the carbon dioxide from the atmosphere and creates a weak acid that falls to Earth and wears away silicate rocks the surface. The byproducts are carried by streams and rivers to the ocean where the carbon is eventually locked away in sedimentary rocks, the scientists said.

"It has long been hypothesized that the balance between carbon dioxide entering the atmosphere from volcanoes and being pulled out by weathering over millions of years holds the temperature of the planet relatively constant," Brantley said. "The key is when there is more carbon dioxide in the atmosphere and the planet gets hotter, weathering goes faster and pulls more carbon dioxide out. And when the planet is cooler, weathering slows down."

But much remains unknown about how sensitive weathering is to changing temperatures, partly because of the long spatial and time scales involved.

"In a soil profile, you are seeing a picture of soil where the camera shutter was open for sometimes a million years -- there are integrated processes happening for a million years and you're trying to compare that with a two-year flask experiment," Brantley said.

Brantley said the field of critical zone science -- which examines landscapes from the tallest vegetation to the deepest groundwater -- has helped scientists better understand the complex interactions that influence weathering.

For example, rocks must fracture for water to get in cracks and start breaking down the materials. For that to happen, the rock must have large, exposed surface areas, and that is less likely to happen in regions where soil is deeper.

"It's only when you start crossing spatial and time scales that you start seeing what's really important," Brantley said. "Surface area is really important. You can measure all the rate constants you want for that solution in the lab, but until you can tell me how does surface area form out there in the natural system, you are never going to be able to predict the real system."

The scientists reported in the journal Science that temperature sensitivity measurements in the laboratory were lower than estimates from soils and rivers in their study. Using observations from the lab and field sites, they upscaled their findings to estimate the global temperature dependance of weathering.

Their model may be helpful for understanding how weathering will respond to future climate change, and in evaluating human-made attempts to increase weathering to draw more carbon dioxide from the atmosphere -- like carbon sequestration.

"One idea has been to enhance weathering by digging up a lot of rock, grinding it, transporting it and putting it out in the fields to let weathering happen," Brantley said. "And that will work -- it's already working. The problem is, it's a very slow process."

Though warming may speed up weathering, pulling all the carbon dioxide out of the atmosphere that humans have added could take thousands or hundreds of thousands of years, the scientists said.

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Fossil discovery in storeroom cupboard shifts origin of modern lizard back 35 million years

A specimen retrieved from a cupboard of the Natural History Museum in London has shown that modern lizards originated in the Late Triassic and not the Middle Jurassic as previously thought.

This fossilised relative of living lizards such as monitor lizards, gila monsters and slow worms was identified in a stored museum collection from the 1950s, including specimens from a quarry near Tortworth in Gloucestershire, South West England. The technology didn't exist then to expose its contemporary features.

As a modern-type lizard, the new fossil impacts all estimates of the origin of lizards and snakes, together called the Squamata, and affects assumptions about their rates of evolution, and even the key trigger for the origin of the group.

The team, led by Dr David Whiteside of Bristol's School of Earth Sciences, have named their incredible discovery Cryptovaranoides microlanius meaning 'small butcher' in tribute to its jaws that were filled with sharp-edged slicing teeth.

Dr Whiteside explained: "I first spotted the specimen in a cupboard full of Clevosaurus fossils in the storerooms of the Natural History Museum in London where I am a Scientific Associate. This was a common enough fossil reptile, a close relative of the New Zealand Tuatara that is the only survivor of the group, the Rhynchocephalia, that split from the squamates over 240 million years ago.

"Our specimen was simply labelled 'Clevosaurus and one other reptile.' As we continued to investigate the specimen, we became more and more convinced that it was actually more closely related to modern day lizards than the Tuatara group.

"We made X-ray scans of the fossils at the University, and this enabled us to reconstruct the fossil in three dimensions, and to see all the tiny bones that were hidden inside the rock."

Cryptovaranoides is clearly a squamate as it differs from the Rhynchocephalia in the braincase, in the neck vertebrae, in the shoulder region, in the presence of a median upper tooth in the front of the mouth, the way the teeth are set on a shelf in the jaws (rather than fused to the crest of the jaws) and in the skull architecture such as the lack of a lower temporal bar. There is only one major primitive feature not found in modern squamates, an opening on one side of the end of the upper arm bone, the humerus, where an artery and nerve pass through. Cryptovaranoides does have some other, apparently primitive characters such as a few rows of teeth on the bones of the roof of the mouth, but experts have observed the same in the living European Glass lizard and many snakes such as Boas and Pythons have multiple rows of large teeth in the same area. Despite this, it is advanced like most living lizards in its braincase and the bone connections in the skull suggest that it was flexible.

"In terms of significance, our fossil shifts the origin and diversification of squamates back from the Middle Jurassic to the Late Triassic," says co-author Professor Mike Benton. "This was a time of major restructuring of ecosystems on land, with origins of new plant groups, especially modern-type conifers, as well as new kinds of insects, and some of the first of modern groups such as turtles, crocodilians, dinosaurs, and mammals.

"Adding the oldest modern squamates then completes the picture. It seems these new plants and animals came on the scene as part of a major rebuilding of life on Earth after the end-Permian mass extinction 252 million years ago, and especially the Carnian Pluvial Episode, 232 million years ago when climates fluctuated between wet and dry and caused great perturbation to life."

PhD research student Sofia Chambi-Trowell commented: "The name of the new animal, Cryptovaranoides microlanius, reflects the hidden nature of the beast in a drawer but also in its likely lifestyle, living in cracks in the limestone on small islands that existed around Bristol at the time. The species name, meaning 'small butcher,' refers to its jaws that were filled with sharp-edged slicing teeth and it would have preyed on arthropods and small vertebrates."

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Dead fish breathes new life into the evolutionary origin of fins and limbs

A trove of fossils in China, unearthed in rock dating back some 436 million years, have revealed for the first time that the mysterious galeaspids, a jawless freshwater fish, possessed paired fins.

The discovery, by an international team, led by Min Zhu of the Institute of Vertebrate Palaeontology and Palaeoanthropology, Bejiing and Professor Philip Donoghue from the University of Bristol's School of Earth Sciences, shows the primitive condition of paired fins before they separated into pectoral and pelvic fins, the forerunner to arms and legs.

Until now, the only surviving fossils of galeaspids were heads, but these new fossils originating in the rocks of Hunan Province and Chongqing and named Tujiaaspis after the indigenous Tujia people who live in this region, contain their whole bodies.

Theories abound on the evolutionary beginnings of vertebrate fins and limbs -- the evolutionary precursors of arms and legs -- mostly based on comparative embryology. There is a rich fossil record, but early vertebrates either had fins or they didn't. There was little evidence for their gradual evolution.

First author Zhikun Gai, a University of Bristol alumnus, said: "The anatomy of galeaspids has been something of a mystery since they were first discovered more than half a century ago. Tens of thousands of fossils are known from China and Vietnam, but almost all of them are just heads -- nothing has been known about the rest of their bodies -- until now.

"The new fossils are spectacular, preserving the whole body for the first time and revealing that these animals possessed paired fins that extended continuously, all the way from the back of the head to the very tip of the tail. This is a great surprise since galeaspids have been thought to lack paired fins altogether."

Corresponding author Professor Donoghue said: "Tujiaaspis breathes new life into a century old hypothesis for the evolution of paired fins, through differentiation of pectoral (arms) and pelvic (legs) fins over evolutionary time from a continuous head-to-tail fin precursor.

"This 'fin-fold' hypothesis has been very popular but it has lacked any supporting evidence until now. The discovery to Tujiaaspis resurrects the fin-fold hypothesis and reconciles it with contemporary data on the genetic controls on the embryonic development of fins in living vertebrates."

Corresponding author Min Zhu of VPP, Beijing, added "Tujiaaspis shows the primitive condition for paired fins first evolved. Later groups, like the jawless osteostracans show the first evidence for the separation of muscular pectoral fins, retaining long pelvic fins that reduced to the short muscular fins in jawed vertebrates, such as in groups like placoderms and sharks. Nevertheless, we can see vestiges of elongate fin-folds in the embryos of living jawed fishes, which can be experimentally manipulated to reproduce them. The key question is why did fins first evolve in this way?"

Bristol's Dr Humberto Ferron used computational engineering approaches to simulate the behaviour of models of Tujiaaspis with and without the paired fins. The co-author said: "The paired fins of Tujiaaspis act as hydrofoils, passively generating lift for the fish without any muscular input from the fins themselves. The lateral fin-folds of Tujiaaspis allowed it to swim more efficiently."

Co-author Dr Joseph Keating at Bristol modelled the evolution of paired fins. He said: "Fossil jawless vertebrates display a dizzying array of fin types, which has provoked extensive debate about the evolution of paired fins.

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Surprise finding suggests 'water worlds' are more common than we thought

Water is the one thing all life on Earth needs, and the cycle of rain to river to ocean to rain is an essential part of what keeps our planet's climate stable and hospitable. When scientists talk about where to search for signs of life throughout the galaxy, planets with water are always at the top of the list.

A new study suggests that many more planets may have large amounts of water than previously thought -- as much as half water and half rock. The catch? All that water is probably embedded in the rock, rather than flowing as oceans or rivers on the surface.

"It was a surprise to see evidence for so many water worlds orbiting the most common type of star in the galaxy," said Rafael Luque, first author on the new paper and a postdoctoral researcher at the University of Chicago. "It has enormous consequences for the search for habitable planets."

Planetary population patterns

Thanks to better telescope instruments, scientists are finding signs of more and more planets in distant solar systems. A larger sample size helps scientists identify demographic patterns -- similar to how looking at the population of an entire town can reveal trends that are hard to see at an individual level.

Luque, along with co-author Enric Pallé of the Institute of Astrophysics of the Canary Islands and the University of La Laguna, decided to take a population-level look at a group of planets that are seen around a type of star called an M-dwarf. These stars are the most common stars we see around us in the galaxy, and scientists have catalogued dozens of planets around them so far.

But because stars are so much brighter than their planets, we cannot see the actual planets themselves. Instead, scientists detect faint signs of the planets' effects on their stars -- the shadow created when a planet crosses in front of its star, or the tiny tug on a star's motion as a planet orbits. That means many questions remain about what these planets actually look like.

"The two different ways to discover planets each give you different information," said Pallé. By catching the shadow created when a planet crosses in front of its star, scientists can find the diameter of the planet. By measuring the tiny gravitational pull that a planet exerts on a star, scientists can find its mass.

By combining the two measurements, scientists can get a sense of the makeup of the planet. Perhaps it's a big-but-airy planet made mostly out of gas like Jupiter, or a small, dense, rocky planet like Earth.

These analyses had been done for individual planets, but much more rarely for the entire known population of such planets in the Milky Way galaxy. As the scientists looked at the numbers -- 43 planets in all -- they saw a surprising picture emerging.

The densities of a large percentage of the planets suggested that they were too light for their size to be made up of pure rock. Instead, these planets are probably something like half rock and half water, or another lighter molecule. Imagine the difference between picking up a bowling ball and a soccer ball: they're roughly the same size, but one is made up of much lighter material.

Searching for water worlds

It may be tempting to imagine these planets like something out of Kevin Costner's Waterworld: entirely covered in deep oceans. However, these planets are so close to their suns that any water on the surface would exist in a supercritical gaseous phase, which would enlarge their radius. "But we don't see that in the samples," explained Luque. "That suggests the water is not in the form of surface ocean."

Instead, the water could exist mixed into the rock or in pockets below the surface. Those conditions would be similar to Jupiter's moon Europa, which is thought to have liquid water underground.

"I was shocked when I saw this analysis -- I and a lot of people in the field assumed these were all dry, rocky planets," said UChicago exoplanet scientist Jacob Bean, whose group Luque has joined to conduct further analyses.

The finding matches a theory of exoplanet formation that had fallen out of favor in the past few years, which suggested that many planets form farther out in their solar systems and migrate inward over time. Imagine clumps of rock and ice forming together in the cold conditions far from a star, and then being pulled slowly inward by the star's gravity.

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Martian rock-metal composite shows potential of 3D printing on Mars

A small amount of simulated crushed Martian rock mixed with a titanium alloy made a stronger, high-performance material in a 3D-printing process that could one day be used on Mars to make tools or rocket parts. The parts were made by Washington State University researchers with as little as 5% up to 100% Martian regolith, a black powdery substance meant to mimic the rocky, inorganic material found on the surface of the red planet. While the parts with 5% Martian regolith were strong, the 100% regolith parts proved brittle and cracked easily. Still, even high-Martian content materials would be useful in making coatings to protect equipment from rust or radiation damage.

A little Martian dust appears to go a long way. A small amount of simulated crushed Martian rock mixed with a titanium alloy made a stronger, high-performance material in a 3D-printing process that could one day be used on Mars to make tools or rocket parts.

The parts were made by Washington State University researchers with as little as 5% up to 100% Martian regolith, a black powdery substance meant to mimic the rocky, inorganic material found on the surface of the red planet.

While the parts with 5% Martian regolith were strong, the 100% regolith parts proved brittle and cracked easily. Still, even high-Martian content materials would be useful in making coatings to protect equipment from rust or radiation damage, said Amit Bandyopadhyay, corresponding author on the study published in the International Journal of Applied Ceramic Technology.

"In space, 3D printing is something that has to happen if we want to think of a manned mission because we really cannot carry everything from here," said Bandyopadhyay, a professor in WSU's School of Mechanical and Materials Engineering. "And if we forgot something, we cannot come back to get it."

Bringing materials into space can be extremely expensive. For instance, the authors noted it costs about $54,000 for the NASA space shuttle to put just one kilogram of payload (about 2.2 pounds) into Earth orbit. Anything that can be made in space, or on planet, would save weight and money -- not to mention if something breaks, astronauts would need a way to repair it on site.

Bandyopadhyay first demonstrated the feasibility of this idea in 2011 when his team used 3D-printing to manufacture parts from lunar regolith, simulated crushed moon rock, for NASA. Since then, space agencies have embraced the technology, and International Space Station has its own 3D-printers to manufacture needed materials on site and for experiments.

For this study, Bandyopadhyay along with graduate students Ali Afrouzian and Kellen Traxel, used a powder-based 3D printer to mix the simulated Martian rock dust with a titanium alloy, a metal often used in space exploration for its strength and heat-resistant properties. As part of the process, a high-powered laser heated the materials to over 2,000 degrees Celsius (3,632 F). Then, the melted mix of Martian regolith-ceramic and metal material flowed onto a moving platform that allowed the researchers to create different sizes and shapes. After the material cooled down, the researchers tested it for strength and durability.

The ceramic material made from 100% Martian rock dust cracked as it cooled, but as Bandyopadhyay pointed out it could still make good coatings for radiation shields as cracks do not matter in that context. But just a little Martian dust, the mixture with 5% regolith, not only did not crack or bubble but also exhibited better properties than the titanium alloy alone, which meant it could be used to make lighter weight pieces that could still bear heavy loads.

"It gives you a better, higher strength and hardness material, so that can perform significantly better in some applications," he said.

This study is just a start, Bandyopadhyay said, and future research may yield better composites using different metals or 3D-printing techniques.

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Scientists release first analysis of rocks plucked from speeding asteroid

After a six-year journey, a plucky spacecraft called Hayabusa2 zinged back into Earth's atmosphere in late 2020 and landed deep in the Australian outback. When researchers from the Japanese space agency JAXA opened it, they found its precious payload sealed and intact: a handful of dirt that Hayabusa2 managed to scoop off the surface of a speeding asteroid.

Scientists have now begun to announce the first results from the analysis of this extraordinary sample. What they found suggests that this asteroid is a piece of the same stuff that coalesced into our sun four-and-a-half billion years ago.

"We previously only had a handful of these rocks to study, and all of them were meteorites that fell to Earth and were stored in museums for decades to centuries, which changed their compositions," said geochemist Nicolas Dauphas, one of the three University of Chicago researchers who worked with a Japan-led international team of scientists to analyze the fragments. "Having pristine samples from outer space is simply incredible. They are witnesses from parts of the solar system that we have not otherwise explored."

'It's spectacular'

In 2018, Hayabusa2 landed atop a moving asteroid named Ryugu and collected particles from above and below its surface. After spending a year and a half orbiting the asteroid, it returned to Earth with a sealed capsule containing about five grams of dust and rock. Scientists around the world have been eagerly anticipating the unique sample -- one that could help redefine our understanding of how planets evolve and how our solar system formed.

Scientists are particularly excited because these particles would never have reached Earth without the protective barrier of a spacecraft.

"Usually, all we get to study of asteroids is the pieces that are big enough to make it to the ground as meteorites," said UChicago geochemist Andrew M. Davis, another member of the analysis team. "If you took this handful and dropped it in the atmosphere, it would burn up. You would lose it, and a lot of evidence about the history of this asteroid would go with it.

"We really haven't had a sample like this before. It's spectacular."

Davis, Dauphas and UChicago colleague Reika Yokochi are all part of a team assembled to help Japanese researchers analyze the samples. Each part of the capsule's contents is being rigorously studied. Yokochi is part of a team that is analyzing the gases that were trapped in the capsule or in the dirt. Dauphas and Davis are part of a team that is studying the chemical and isotopic compositions grains to reveal their history.

The first compilation of these results, reported in Science on June 9, reveal the makeup of Ryugu.

The rock is similar to a class of meteorites known as "Ivuna-type carbonaceous chondrites." These rocks have a similar chemical composition to what we measure from the sun and are thought to date back to the very beginnings of the solar system approximately four-and-a-half billion years ago -- before the formation of the sun, the moon and Earth. [should Moon be capitalized to distinguish it from other moons?]

Back then, all that existed was a gigantic, rotating cloud of gas. Scientists think that most of that gas was pulled into the center and formed the star we know as the sun. As the remnants of that gas expanded into a disk and cooled, it transformed into rocks, which still float around the solar system today; it appears Ryugu may be one of them.

Scientists said the fragments show signs of having been soaked in water at some point. "One must picture an aggregate of ice and dust floating in space, that turned into a giant mudball when ice was melted by nuclear energy from the decay of radioactive elements that were present in the asteroid when it formed," said Dauphas. But surprisingly, today the rock itself appears to be relatively dry.

Using radioisotope dating, they estimated that Ryugu was altered by water circulation only about five million years after the solar system formed.

These findings are particularly interesting to researchers because they hint at similar formation conditions between comets and some asteroids such as Ryugu.

"By examining these samples, we can constrain the temperatures and conditions that must have been occurring in their lifetimes, and try to understand what happened," Yokochi explained.

She compared the process to trying to figure out how a soup was made, but with only the final result rather than the recipe: "We can take the soup and separate the ingredients, and try to tell from their conditions how much it was heated and in what order."

The scientists noted that a percentage of the find will be set aside so that we can analyze them in the future with more advanced technology -- much as we did with lunar samples from Apollo.

"After we got moon samples from Apollo 50 years ago, our ideas about how the moon formed completely changed," Davis said. "We're still learning new things from them, because our instruments and technology have advanced.

"The same will be true for these samples. This is a gift that keeps on giving."

This mission is the first of several international missions that will bring back samples from another asteroid named Bennu, as well as unexplored areas on our moon, Mars, and Mars' moon Phobos. This should all be taking place in the next 10 to 20 years.

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