Tag Archives: minerals

Mars’ water didn’t escape; it’s trapped in the red crust

New research from Caltech and JPL suggests that Mars never lost its water — it just drank it up, so to speak.

Digital rendering of Mars. Image credits Kevin Gill via Wikimedia.

Billions of years ago, our red neighbor had an atmosphere and maintained liquid water on its surface. We know this because Mars’ surface is littered with ancient river- and lake beds. The prevailing wisdom today is that once the planet lost its geological activity and thus, its magnetic field, it lost, in turn, its atmosphere and surface water, which were blown away by solar winds.

But new research says that at least the water might still be there. According to the findings, anywhere between 30% to 99% of its original water is trapped in minerals within the Martian crust.

Better red than dry

“Atmospheric escape doesn’t fully explain the data that we have for how much water actually once existed on Mars,” says Caltech PhD candidate Eva Scheller, lead author of the paper.

According to the team, around four billion years ago Mars had enough liquid water to cover its entire surface in an ocean between 100 to 1,500 meters deep. That, they explain, would be roughly equivalent to half the entire volume of the Atlantic Ocean. However, around three billion years ago, Mars looked as it does today — dry as bone. The planet’s low gravitational pull was believed to have allowed this water to escape to space over time under the action of solar winds.

For the study, the team looked at how much water Mars has in all of its forms, as well as the chemical composition of its current atmosphere and crust. They used data beamed back by virtually every Mars rover and orbiter and that we gleaned from meteorites. A particular point of interest for them was to analyze the ratio of deuterium to hydrogen (D/H) isotopes in this water.

The vast majority of water molecules have ‘vanilla’ hydrogen in their molecules — hydrogen atoms with one proton in their nucleus. Around 0.02% of all naturally-occurring water molecules in the Universe, however, include deuterium atoms — “heavy” hydrogen, which has one proton and one neutron at its core — instead.

The value of the D/H ratio in Mars’ atmosphere over time. Image credits L. J. Hallis via Researchgate.

Regular hydrogen is also known as protium and, because of its lower atomic weight, should have an easier time escaping a planet’s gravity into space. But this also means that such a process would increase the D/H ratio in Mars’ current atmosphere (i.e. increase the presence of deuterium above the 0.02% mark), which is something we can check. What the paper argues, however, is that this escape process can’t explain where all the water that’s missing has gone, and the D/H ratio, by itself. Instead, the team proposes that another mechanism worked at the same time: the trapping of water in minerals inside the planet’s crust. Together, the team explains, they could produce the conditions we see today on Mars.

The interaction between water and silicate rocks generates minerals such as clay through a process called (chemical) weathering. These minerals often contain water in their structure. While chemical weathering takes place on both Earth and Mars all the time, Earth is tectonically active, meaning weathered minerals eventually find their way back into the mantle where they’re recycled, which brings the water back out through volcanic eruptions. Since Mars isn’t tectonically active, the water trapped in its crust is no longer being cycled back out.

“Atmospheric escape clearly had a role in water loss, but findings from the last decade of Mars missions have pointed to the fact that there was this huge reservoir of ancient hydrated minerals whose formation certainly decreased water availability over time,” says Ehlmann.

“All of this water was sequestered fairly early on, and then never cycled back out,” adds Scheller.

The team previously used a similar approach to understand how habitability on Mars evolved over time by tracking carbon dioxide, currently the main ingredient of its atmosphere. In the future, they plan to continue examining the processes through which Mars’ water disappeared in their lab, and later expand their research to nitrogen and sulfur-rich minerals. Samples to-be-recovered by the Perseverance rover will help confirm or deny their current hypothesis.

The paper “Long-term drying of Mars by sequestration of ocean-scale volumes of water in the crust” has been published in the journal Science.

Parisite-(La) is a newly discovered mineral species that was predicted by big data analysis. It was discovered in Brazil's northeast state of Bahia. Credit: Luiz Menezes.

Big Data predicts 1,500 mineral species are waiting to be found. Ten have already been discovered

Parisite-(La) is a newly discovered mineral species that was predicted by big data analysis. It was discovered in Brazil's northeast state of Bahia. Credit: Luiz Menezes.

Parisite-(La) is a newly discovered mineral species that was predicted by big data analysis. It was discovered in Brazil’s northeast state of Bahia. Credit: Luiz Menezes.

The same approach that Facebook uses to graph networks or scientists employ to map the spread of diseases was applied to predict new minerals species and deposits. It’s the first time network theory and big data — a buzz word that describes the uses of huge data sets to reveal patterns and make predictions otherwise difficult to obtain — have been employed to find new minerals.

High-tech geology

We know of about 5,200 mineral species, each of which has a unique combination of chemical composition and atomic structure. There are millions of mineral samples housed in museums, warehouses, universities or private collections, many of which have been neatly described and cataloged. For instance, it’s standard practice for a mineral sample to be tagged with information like the location it was recovered from, the level or occurrence, the age of the deposit or the mineral’s growth rate.

When you combine this information — not on one deposit but a myriad — with data on the surrounding geography, the geological setting, and coexisting minerals, it’s possible to fill in the blanks and infer the existence of not only deposits but also new mineral species.

It’s only recently that the technology has enabled scientists to use such a ‘big data’ approach.

“The quest for new mineral deposits is incessant, but until recently mineral discovery has been more a matter of luck than scientific prediction,” said Dr. Shaunna Morrison of the Deep Carbon Observatory in a statement. “All that may change thanks to big data.”

Just like data scientists use complex data sets to understand social media connections, city traffic or even metabolic pathways, so can the same method apply to mineralogy and petrology. There are really few fields of science where big data can’t help make a breakthrough.

Bearing this in mind, Morrison and colleagues were able to visualize data from multiple variables on thousands of mineral samples sourced from hundreds of thousands of locations around the world. And it was all represented within a single graph which reveals patterns of occurrence and distribution otherwise extremely difficult if not impossible to infer.

From here on, it’s only a matter of filling the gaps of a list of minerals. Moreover, the analysis also tells us where we can dig to find new deposits. Robert Hazen at the Carnegie Institution for Science discusses mineral evolution, mineral ecology, and mineral network analysis in this hour-long lecture embedded below.

Ewingite. Photo Travis Olds.

Ewingite. Photo Travis Olds.

The hunt for new minerals is on

Already, this approach enabled the researchers to predict the existence of 145 missing carbon-bearing minerals and where to find them. To accelerate their discovery, the Deep Carbon Observatory launched the Carbon Mineral Challenge to inspire professional and amateur mineralogists alike to hunt down minerals from this shortlist. Already, ten have been found. Among them is ewingite, the most structurally complex known mineral on Earth. Many more minerals await discovery, though.

“We have used the same kinds of techniques to predict that at least 1,500 minerals of all kinds are ‘missing,’ to predict what some of them are, and where to find them,” Dr. Hazen says.

Analyses of complex mineral datasets also help to untangle some of the intricate relationships between geology and biology, leading to new insights into the co-evolution of the geosphere and biosphere. For instance, mineral networks of igneous rocks can help retrace ‘Bowen’s reaction series’, which tells us how various characteristic minerals form once magma cools. The analysis was so precise that the predicted sequence of minerals matched reality precisely. In the future, mineral networks coupled with data on biomarker molecules can reveal insights on how cells and minerals interact.

Mineral networks can also serve as a powerful learning tool in academia for mineralogy and petrology, helping students visualize rocks, minerals and their relationships.

And of course, the industry could make billions by mining new deposits. Some of the yet to be identified minerals could have remarkable properties that might enable novel products on the market. Really, there are countless applications of big data on minerals and the implications could be far reaching.

“Minerals provide the basis for all our material wealth,” Morisson concluded, “not just precious gold and brilliant gemstones, but in the brick and steel of every home and office, in cars and planes, in bottles and cans, and in every high-tech gadget from laptops to iPhones.”

“Minerals form the soils in which we grow our crops, they provide the gravel with which we pave our roads, and they filter the water we drink.”

“This new tool for understanding minerals represents an important advance in a scientific field of vital interest.”

Findings appeared in the journal American Mineralogist.

Red Skies.

Silica rains helped form Earth’s crust four and a half billion years ago

Earth’s crust may have been formed in part by atmospheric chemicals which settled on the surface as the planet cooled, McGill University researchers report.

Red Skies.

Image credits David Mark.

We know that about 4.5 billion years ago, a planetoid roughly the same size as today’s Mars slammed into early Earth with enough force to melt the whole thing into a ball of magma. The event was so violent that we believe it led to the formation of the Moon and altered the chemical composition of our planet into the iron-rich Earth we know and love today.

Conventional wisdom holds that following this impact, the Earth gradually cooled down and the outer surface of this ball of lava hardened into a crust — in other words, the rocks on the planet’s surface are igneous in origin. But Don Baker and Kassandra Sofonio, a team of earth scientists from McGill University, say that the event played a direct hand in forming the planet’s modern crust. According to their theory, some of the chemical components we see in the crust today were deposited from the super-heated atmosphere left in the wake of the impact.

Igngaseous

Largely speaking, Earth’s crust comes in two flavors: oceanic and continental. Oceanic crust is the stuff plates are formed of, the rocks that cool from magma at mid-ocean rifts (they are igneous) then get subducted and recycled on the other side of the plate. It’s usually pretty thin and it’s what the ocean floor rests on.

Continental crust is the stuff that we actually live on. These thicker slabs of rock form on top of oceanic crust and reach high enough altitudes (usually) to form continents above water — hence their name. The rocks that go into continental crust can come from many different places, but what’s important now is that more than 90% of these rocks are estimated to be formed from silica-rich minerals, such as feldspar and quartz. Which, as you may have guessed, adds up to a lot of silica.

So where did all this silica-rich crustal material come from? The duo says that the collision 4.5 billion years ago turned the atmosphere into high-temperature steam which dissolved the rocks in the surface into a gaseous solution.

“These dissolved minerals rose to the upper atmosphere and cooled off, and then these silicate materials that were dissolved at the surface would start to separate out and fall back to Earth in what we call a silicate rain,” Baker says.

To test their theory, the team recreated the conditions of early Earth in the lab. They used a mix of bulk silicate materials and water which was enclosed in gold palladium capsules, then heated to 727 degrees Celsius (1340 Fahrenheit) at 100 atm to simulate conditions in the atmosphere about 1 million years after the moon-forming impact.

Using previous work on rock-water interactions at high pressure as a starting point, the team successfully recreated a “surprisingly similar” material to the Earth’s modern crust. The authors believe that following the impact, surface silicate rocks would dissolve and separate, rising to the upper layers of the atmosphere. Here, they cooled off enough to crystallize and fall back to Earth in a “silicate rain.” Sofonio christened the process “aerial metasomatism.”

One surprising implication of the paper is that it could provide researchers with a better understanding of how to spot planets fit for human habitation, or even those that harbor alien life.

“This time in early Earth’s history is still really exciting,” he adds. “A lot of people think that life started very soon after these events that we’re talking about. This is setting up the stages for the Earth being ready to support life.”

The paper “A metasomatic mechanism for the formation of Earth’s earliest evolved crust” has been published in the journal Earth and Planetary Science Letters.

Even ubiquitous iron could run short.

We may face a huge shortage of essential raw materials stiffling green energy if governments don’t step up their game

An international team of researchers led by Saleem Ali, Blue and Gold Distinguished Professor of Energy and Environment at the University of Delaware, warns that greater international political and scientific cooperation is needed to secure the resources we’ll need in the future.

Even ubiquitous iron could run short.

Even ubiquitous iron could run short.
Image credits nightowl / Pixabay.

To say that humanity today faces some challenges would be an understatement. Political unrest, climate change, income inequality, drug resistance, they all add up. Still, as a species, we’ve shown a knack for eventually overcoming all the problems that’ve been thrown our way — be them by chance or our own hand. All we need is enough time to think about a solution and enough stuff to put it together and voila! Progress.

But we may be soon running short on the second part, the raw materials, an international team of researchers warns. They say that greater international transparency and a free exchange of geophysical data between countries is needed to secure the future’s supply of raw minerals.

What’s (low) on the menu

The team includes members from the academic, industrial, and government sectors in institutions throughout the U.S., South America, Europe, South Africa, and Australia. They are primarily concerned with future supply of a wide range of technology minerals, which are indispensable in all kinds of industries — from copper wiring in homes or laptop batteries all the way to solar panels and superdense batteries for electric cars. However, they say there’s also cause for concern regarding base metals such as copper or iron ore.

“There are treaties on climate change, biodiversity, migratory species and even waste management of organic chemicals, but there is no international mechanism to govern how mineral supply should be coordinated,” said Ali, who is the paper’s lead author.

They looked at demand records and forecasts, as well as estimates of the sustainability of mineral supplies in the coming decades. They write that current mining operations won’t be able to keep up with the rise in demand, especially considering the fact that “implementation of the Paris Agreement requires technologies that utilize a wide range of minerals in vast quantities.” When push comes to shove, no matter how green our policy and technology gets, if we can’t build it and field it, it won’t do us much good. So we need to up our extraction game.

“Metal recycling and technological change will contribute to sustaining supply, but mining must continue and grow for the foreseeable future to ensure that such minerals remain available to industry,” they conclude.

The materials required for the transition to a low-carbon economy, the stuff that goes into manufacturing clean tech, will be particularly tricky, the researchers say. While base materials are used extensively in current economies –so it’s only a matter of expanding on well-established methods and deposits –traditionally there hasn’t been a wide-scale demand of the more exotic minerals required for clean energy sources, leaving society ill-equipped to meet the extra demand for these materials.

Neodymium is used to make the strongest permanent magnets we know of.

Neodymium is used to make the strongest permanent magnets we know of.
Image credits Brett Jordan / Flickr.

We’ll have to both find suitable deposits and develop more efficient methods of extracting, refining, and handling these elements. Metals like neodymium, terbium, or iridium, although only needed in small quantities, can’t be substituted for anything else in certain clean energy applications and other advanced tech. So while they seem to only make up a tiny part of the overall requirements, they are vital for future applications. A bottleneck in terms of material production for these vital minerals would bottleneck development of the industry and ultimately energy production.

According to the team, the best way to prevent this is to work together. International coordination is needed to determine where to focus future exploration efforts, what areas are likely to be rich or poor in which resources and thus what kind of economic agreements are needed between different countries to make sure that there aren’t any deficiencies anywhere.

Supply and demand

Those of you who think laissez-faire systems are the bee’s knees are probably prickling in horror at the mere thought of international government meddling in the market. But the team points out that the forces which dictate the prices of major commodity minerals don’t (currently) apply to rare earths and other technology minerals.

For example, the largest percentage of exploration investment in a single mineral is in gold, which although highly profitable, is largely used for jewelry. It, along with other major commodity metals such as copper or iron ore are sold on a global market the same way grain or oil is, a market which fluctuates according to supply and demand. But rare earth metals and other technology minerals, however, are sold through individual dealers and prices can vary wildly between them.

Even more, the UN expects global population to reach about 8.5 billion by 2030, which means more demand for these substances in the next decade or so. For your run of the mill goods, take clothes or newspapers, a growth in demand (reflected in a greater price) is swiftly and easily followed by an increase in production. But mineral supply doesn’t follow that same relationship to demand, because of the huge spans of time required to get an exploitation up and running — the horizon for developing a rare earth mineral deposit, from exploration and subsequent discovery to actually mining the thing, is 10 to 15 years, the team says.

Rare earth elements are usually produced as oxides. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium.

Rare earth elements are usually produced as oxides. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium.
Image credits Peggy Greb, US department of agriculture / Wikimedia.

Considering that only about 10% or early exploration efforts result in a mineable deposit, the outlook is even bleaker. Most deposits prospectors find simply aren’t big enough or concentrated enough to be economically viable. Companies can also have a lot of trouble getting exploitation rights or run into zoning problems due to geopolitical factors.

“Countries where minerals are likely to be found may have poor governance, making it higher risk for supply. But production from these countries will be needed to meet global demand. We need to be thinking about this,” Ali said.

The authors also warn that for many of the minerals their paper calls into discussion, there aren’t any substitutes. With so few commercially viable alternatives even for the humble copper wire, it’s simply a matter of produce enough stuff or run short.

Ali and his team hope that the paper will form the foundation of an intergovernmental framework or another similar system which would allow countries to plan and prevent mineral scarcity in the future — as both private and public sectors are dependent on raw materials. They say that quick improvements can be made through expansion of developing organizations, such as the United Nation’s International Resource Panel or the Canadian-led Intergovernmental Panel on Mining Metals and Sustainable Development. Longer-term solutions will need greater international transparency and could include global sharing of geological data and the creation of mechanisms to protect mineral deposit ‘finds’ much like we protect intellectual property.

“It’s about managing the flow of resources from the ground to product to consumer to recycling,” Ali said.

“People have been so concerned about climate change that it’s created a real movement around it. We don’t see this around resource use and recovery, even though it is much closer to us on a daily basis.”

The full paper “Mineral supply for sustainable development requires resource governance” has been published in the journal Nature.

There’s a museum in Japan that honors rocks which resemble human faces

Just a two hours drive northwest of Tokyo, you can find one of the world’s most entertaining museums. It’s called the Chinsekikan, Japanese for ‘hall of curious rocks’, and inside, visitors can find more than 1,700 rocks that look peculiar in some way, 900 of which resemble faces. Among some of the celebrities housed at this Madame Tussaud’s for minerals are E.T., Elvis Presley, and, of course, Jesus Christ.

Where nature is the only artist

The head curator Yoshiko Hayama.

This one of a kind museum was founded by Shozo Hayama who has collected strange-shaped, unaltered rocks for fifty years. Since Hayama passed away in 2010, the museum has been run by Yoshiko Hayama, the late founder’s wife.

Besides the rocks that resemble real and fictional celebrities, among them Japanese sensation Donkey Kong, Mickey Mouse, Nemo the clownfish, or the mercurial Boris Yeltsin, there are also more general human face-resembling rocks such as the ‘chorus rocks’ featured below.

Big "O-faced" rocks.

Big “O-faced” rocks.

The Chinsekikan museum has been featured on many popular Japanese TV shows.  Every rock on display from the collection is completely unaltered keeping true to Shozo Hayama’s legacy — that nature is the only artist.

Elvis

Wrestler and Japanese politician Antonio Inoki

Wrestler and Japanese politician Antonio Inoki

Turtle shell

Turtle shell

Some of the celebrity-lookalike rocks are more convincing than others.

Mickey Mouse

Cold Wind Monjiro from the Japanese novel and TV drama Kogarashi Monjiro

Nemo

Even Mikhail Gorbachev is on the list.

Geologically speaking, the anthropomorphic features you see etched on the rocks are due to weathering of certain minerals and imperfections. Weathering and cracking usually occur along a plane of weakness or a sedimentary layer. Many of the rocks featured in this article, for instance, seem weathered by flowing water. Some minerals are more susceptible to sculpting by natural phenomena than others. Quarts, for instance, is much less likely to weather than micas.

There had to be a Jesus too.

As for what compelled the founder of the museum to amass such a collection, Shozo Hayama likely had some degree of pareidolia, which is the tendency to perceive human traits where none actually exist. It’s what causes some people to claim there are pyramids on Mars shaped like a human face or to see Jesus in pieces of toast or sections of timber. A recent study suggests an anomalous interplay between the brain’s frontal cortex and posterior visual cortex is what leads some people to see faces in objects more often than others. But it is totally normal to notice faces in rocks or other objects because our brains are hard-wired to spot such patterns.

The author's own pareidolia. If this isn't Scumbag Steve, I don't know what rock could ever be.

The author’s own pareidolia. If this isn’t Scumbag Steve, I don’t know what rock could ever be.

Chinsekika definitely looks fun to visit and a welcomed breath of fresh air if you enjoy visiting more traditional geological museums.

All pics via Kotaku, Another Tokyo, Yukawanet, and Sankei Photo.

El Tatio, Chile. Credit: Pixabay, falco.

Martian minerals might bear signatures of ancient life

El Tatio, Chile. Credit: Pixabay, falco.

El Tatio, Chile. Credit: Pixabay, falco.

Almost ten years ago, in 2007, the old timer Spirit rover found opaline silica for the first time on Mars. These rocks are evidence of past hydrothermal or volcanic activity – some kind of heated geological interaction. The discovery marked a turning point in Martian geology, but afterwards, not much consideration was given  to the Home Plate — a plateau of layered rocks that the rover explored in its third year on the Red Planet — and the Gusev Crater where the silica rocks were found. Many years later, researchers from Arizona State University say the features in the rocks found in Gusev Crater are strikingly similar to those collected from active hot springs in Tatio, northern Chile.

Finding signs of past life is still something

“Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures,” the researchers wrote in the study.

Initially, everyone thought the opaline silica deposits found by the Spirit rover formed billions of years ago by fumarole-related acid-sulfate leaching. What they missed, however, were the nodular and millimeter-scale digitate opaline silica structures typically formed by microorganisms living in hot, mineral-rich waters.

Steve Ruff, a planetary scientist at Arizona State University, stumbled one day across a paper describing El Tatio, an incredible hydrothermal system 14,000 feet above sea level. El Tatio is littered with hot springs and geysers channels which contain deposits of opaline silica. Moreover, the site has a low precipitation rate, high mean annual evaporation rate, common diurnal freeze-thaw and extremely high ultraviolet irradiance. All of this makes El Tatio very Mars-like. Ruff was on to something.

The scientist, along with colleagues, traveled to Chile to inspect El Tatio with his own eyes. They collected samples and performed both spectral analysis and high-res imaging. What they later found was that the silica minerals from El Tatio form in shallow, hydrothermal waters. The opaline silica from the site that most closely resemble minerals from Mars were those that were formed in the presence of microbes. Specifically, the nodular tiny features on the minerals form when biofilms — clumped-together mats of microorganisms — stick to them.

Opaline silica: on the left samples collected from Mars, El Tatio on the right. Credit: ASU.

Opaline silica: on the left samples collected from Mars, El Tatio on the right. Credit: ASU.

“Our results demonstrate that the more Mars-like conditions of El Tatio produce unique deposits, including biomediated silica structures, with characteristics that compare favorably with the Home Plate silica outcrops. The similarities raise the possibility that the Martian silica structures formed in a comparable manner,” the researchers noted at the end of their travels and studies.

 

“Because we can neither prove nor disprove a biological origin for the microstromatolite-like digitate silica structures at Home Plate, they constitute a potential biosignature according to this definition,” they concluded.

On May 9, 2009, the Spirit rover boggled down, trapped in Mars’ soft soil. The rover continued to function as a stationary measurement platform until it was discontinued in May. 2011. That being said, our only shot of finding out for real whether the opaline silica from Gusev Crater genuinely bears signs of life is to send another rover. NASA has such a mission planned for 2020 but it’s yet to consider a drop off location. In light of these recent findings, maybe Gusev Crater might prove appealing.

 

fungus

Fungi eat yummy minerals from rocks using acid and mechanical force

Fungi were thought to have a minimal impact on minerals’ bioweathering but recent study suggests that fungi are a lot more aggressive than they were given credit. They use acid to access precious nutrients like iron and burrow deep into rocks using mechanical force to further their reach.

fungus

MIcroscope view of the Talaromyces flavus fungus collected from a mine in China. Credit: Henry Teng

Researchers at George Washington University collected a fungus called Talaromyces flavus from a mine in Donghai, China. They then brought the fungus home and let it munch on a mineral called lizardite in a controlled lab setting. Previously, researchers who studied mineral degradation at the hand of fungal or microbial activity would mix the organisms with crushed minerals. In our case,   T. flavus was allowed to eat the mineral whole for four days, mimicking a fungus-mineral interface interaction found in the real world.

After those four days, the team led by  Henry Teng, a geochemist at George Washington University, washed the lizardite mineral and inspected the marks left by T. flavus. The results were pretty astonishing: many long, thin channels and small, round pits — the marking of a fungus feast — littered the mineral’s surface.

fungus eating mineral

A tiny, 125-micrometer-long channel carved out of rock by the fungus. Credit: Henry Teng

The methods of attack were also explained. First, the fungus releases spores that drop the pH by a factor of ten. This highly acidic environment dissolves the mineral, forming a soup which the fungus can easily ingest, but not before releasing a chemical called siderophore which facilitates iron intake. Once the iron at the surface of the mineral is depleted, T. flavus extends fillaments called  hyphae which burrow inside,  leaving behind channels stretching 200–2000 nanometers.

Intriguingly, the mineral had become amorphous in some parts where it should have had an orderly crystalline structure. This observation suggests the fungus used mechanical force to destroy the mineral, in addition to chemical forces.

Another experiment was set up, this time the lizardite was crushed in mixed in a solution with the fungus. Far less of the mineral was degraded in this suspended setting, suggesting interface interaction is a lot more powerful. Teng and colleagues claim that the fungus is responsible for forty to fifty percent of the total bioweathering of the mineral, compared to only one percent previously thought.

“Compared to bacteria, fungi are overlooked, understudied, and very few studies [looked] at these interfaces between fungi and mineral,” said Steeve Bonneville , a biogeochemist at the Free University of Brussels in Belgium who was not involved in the paper, which he called “a very solid study.” The new research provides evidence that “fungi can be a major player in mineral alteration and more generally in biogeochemical cycles,” Bonneville said.

The researchers only studied one species of fungus though, and some traits may be unique to T. flavus. The study‘s results might motivate others to investigate this interaction using other species.

Why is all this important? Apart from understanding how fungi and minerals interact, the findings will help build better models of plant growth. Trees and vegetables rely on mineral nutrients to grow. “Most of the nutrients in rock and soil are in geological form,” Teng said. “Roots cannot directly use that. Plants depend on the fungi to colonize their roots.”

Pyrite, a common mineral. Image: Pixabay

Catalog of rarest Earth minerals might shed light on how the planet formed, but also origin of life

There are over 5,000 mineral species identified by scientists thus far, but fewer than 100 make up the entire planet’s crust. The rest are so rare, short lived and notoriously difficult to replicate that you’d barely know they’re here. Not understating the importance of such minerals — which could offer clues on how the planet formed, but also lead to new industrial applications — researchers from the United States cataloged the 2,500 rarest minerals on the planet.

Pyrite, a common mineral. Image: Pixabay

Pyrite, a common mineral. Image: Pixabay

A mineral is certain kind of substance that is naturally occurring, inorganic, solid and of an ordered internal structure, which a specific chemical composition. Steel is not a mineral, because it’s an alloy invented by humans. Wood isn’t a mineral because it’s made by an organism.

Minerals are vital for human society. We need minerals to make something as simple as a pencil, whose ‘lead’ is made out of graphite and clay minerals. A smartphone has dozens of different minerals mined from all over the world.

Ichnusaite is a rare mineral included in the catalog — a subterranean mash-up of the radioactive element thorium and lead-like molybdenum, with only one specimen ever found, in Sardinia. Credit: American Mineralogist / Paulo Biagioni et al

The authors of the new rare Earth mineral catalog are  Dr Robert Hazen, from the Carnegie Institution in Washington DC, and Prof Jesse Ausubel of The Rockefeller University, in New York. The two listed the minerals under four broad categories that describe the conditions under which they form, how rare their ingredients are, how ephemeral they are, and the limitations on their sampling. Minerals like feldspar, quartz and mica are ubiquitous, but others are much rarer. A decimal variation in temperature or pressure will produce a different kind of mineral or none at all. Some are transformed simply by the touch of light or water. It’s believed there are still 1,500 minerals we haven’t discovered yet.

“Fingerite is like a ‘perfect storm of rarity’,” said Dr Hazen.

“It occurs only on the flanks of the Izalco Volcano in El Salvador – an incredibly dangerous place with super-hot fumeroles.

“It’s made of rare elements – vanadium and copper have to exist together, and it forms under an extremely narrow range of conditions. If you just change the ratio of copper to vanadium slightly, you get a different mineral. And every time it rains, fingerite washes away.”

With this new catalog at hand, scientists can not only better estimate what stocks of a certain minerals can be found in the Earth’s crust, but also where. This will prove invaluable for some industries. The scientific value is also important since mineral species composition tells us how different  Earth’s chemistry is from Mars’ or Venus’, for instance. Finally, though speculative, rare minerals may offer clues as to the origin of life. Many minerals, it is said, would not have existed were it not for life which altered their chemical environment. “We live on a planet with remarkable mineralogical diversity, featuring countless variations of color and form, richly varied geochemical niches and captivating compositional and structural complexities,” the authors note in the paper published in American Mineralogist.

Molecules of collagen (top) next to molecules of a crystal of hydroxyapatite (bottom). (c) MIT

Atomic structure of bone deciphered for the first time

Bone is a really awesome material, being hard and flexible at the same time. For something so ubiquitous and studied for so long, it might come as a surprise to some of you to hear that the molecular bone structure of bone has alluded scientists for such a long while. This is because, even though the constituent elements that make up bone have been known for a long time, how they line together to form such an intricate structure has been very difficult to identify, until recently after MIT researchers used supercomputers to reveal with almost atomic precision the precise structure of bone. Their work is a significant step forward in material science, marking a milestone. The researchers hope they can synthesize bone fibers soon enough, while furthering their understanding of how some diseases attack bones.

Molecules of collagen (top) next to molecules of a crystal of hydroxyapatite (bottom).  (c) MIT

Molecules of collagen (top) next to molecules of a crystal of hydroxyapatite (bottom). (c) MIT

Rather curiously, bone is made out of two materials:  a soft, flexible biomolecule called collagen and a hard, brittle form of the mineral apatite (hydroxyapatite). Each substance, taken individually, has nothing to do with bone, but when combined in a very complex manner, they form something that is simultaneously hard, tough and slightly flexible.

For years scientists have been studying bone at a molecular level, using tools such as atomic force microscopes to probe the material at an atomic level, however using such methods imaging is only possible in 2-D. Bone, taken as a whole, is an intricate molecular 3-D structure that can not be decoded by looking from a 2-D perspective.

“It’s easy to get images of bone, but it’s hard to see exactly where the minerals are located inside the collagen,” says Shu-Wei Chang, a CEE graduate student who was a co-author of the paper.

Using a supercomputer, engineers from MIT, led by civil engineer and materials scientist Markus Buehler, calculated what fibers of collagen, strengthened with hydroxyapatite crystals, look like. To verify their findings, they made a comparative study with laboratory findings. This whole process required several iterations before they could come to a sound conclusion and took several months to complete, something very important to note since the same process would have taken years and years to complete not too long ago. Thankfully supercomputing has evolved exponentially and MIT were quick to update their stock.

What makes up bones

According to their results, the MIT researchers found that the key to the bone’s fantastic molecular structure lies in how the hydroxyapatite crystals align with collagen. Hydroxyapatite grains are tiny, thin platelets just a few nanometers (billionths of a meter) across, and are deeply embedded in the collagen matrix. The two constituents are bound together by electrostatic interactions, which allows them to slip somewhat against each other without breaking. Large pieces of hydroxyapatite are brittle, like chalk, but at such small sizes, the mineral is actually ductile. The researchers also found that under stress tests, the mineral parts of the fibers took on four times as much stress as the collagen portions, whereas bending happened almost exclusively in the collagen.

“In this arrangement of tiny hydroxyapatite grains embedded in the collagen matrix, the two materials can each contribute the best of their properties,” Buehler says. “Hydroxyapatite takes most of the forces in the material, whereas collagen takes most of the stretching.”

Buehler and his team hope they can next create bone fibers in the lab. Also, now with a better understanding of what makes up bone and how its constituent elements are arranged, doctors may find what goes wrong in certain diseases, including osteoporosis and brittle bone disease.

“We can use this model to understand how a bone becomes more brittle,” says Arun Nair, a CEE postdoc who was the first author of the paper. For example, collagen is made up of thousands of amino acids, but “if only one of those amino acids is altered, it changes the way the minerals form” inside the bone, Nair says.

“That’s why this model is so critical,” he adds. Without it, you could observe how bone changes as a result of disease, but “you don’t know why. Now, we can see how a very tiny change … changes the way the mineral grows, or how the forces and deformation are distributed.”

The findings were reported in the journal Nature Communications.