Shale could be long-term home for problematic nuclear waste

Shale, the source of the United States’ current natural gas boom, could help solve another energy problem: what to do with radioactive waste from nuclear power plants. The unique properties of the sedimentary rock and related clay-rich rocks make it ideal for storing the potentially dangerous spent fuel for millennia, according to a geologist studying possible storage sites who made a presentation here today.

The talk was one of more than 10,000 presentations at the 247th National Meeting & Exposition of the American Chemical Society (ACS), the world’s largest scientific society, taking place here through Thursday.

About 77,000 tons of spent nuclear fuel currently sit in temporary above-ground storage facilities, said Chris Neuzil, Ph.D., who led the research, and it will remain dangerous for tens or hundreds of thousands of years or longer.

“Surface storage for that length of time requires maintenance and security,” he said. “Hoping for stable societies that can continue to provide those things for millennia is not a good idea.” He also pointed out that natural disasters can threaten surface facilities, as in 2011 when a tsunami knocked cooling pumps in storage pools offline at the Fukushima Daiichi nuclear power plant in Japan.

Since the U.S. government abandoned plans to develop a long-term nuclear-waste storage site at Yucca Mountain in Nevada in 2009, Neuzil said finding new long-term storage sites must be a priority. It is crucial because nuclear fuel continues to produce heat and harmful radiation after its useful lifetime. In a nuclear power plant, the heat generated by uranium, plutonium and other radioactive elements as they decay is used to make steam and generate electricity by spinning turbines. In temporary pool storage, water absorbs heat and radiation. After spent fuel has been cooled in a pool for several years, it can be moved to dry storage in a sealed metal cask, where steel and concrete block radiation. This also is a temporary measure.

But shale deep under the Earth’s surface could be a solution. France, Switzerland and Belgium already have plans to use shale repositories to store nuclear waste long-term. Neuzil proposes that the U.S. also explore the possibility of storing spent nuclear fuel hundreds of yards underground in layers of shale and other clay-rich rock. He is with the U.S. Geological Survey and is currently investigating a site in Ontario with the Canadian Nuclear Waste Management Organization.

Neuzil explained that these rock formations may be uniquely suited for nuclear waste storage because they are nearly impermeable – barely any water flows through them. Experts consider water contamination by nuclear waste one of the biggest risks of long-term storage. Unlike shale that one might see where a road cuts into a hillside, the rocks where Neuzil is looking are much more watertight. “Years ago, I probably would have told you shales below the surface were also fractured,” he said. “But we’re seeing that that’s not necessarily true.” Experiments show that water moves extremely slowly through these rocks, if at all.

Various circumstances have conspired to create unusual pressure systems in these formations that result from minimal water flow. In one well-known example, retreating glaciers in Wellenberg, Switzerland, squeezed the water from subsurface shale. When they retreated, the shale sprung back to its original shape faster than water could seep back in, creating a low-pressure pocket. That means that groundwater now only flows extremely slowly into the formation rather than through it. Similar examples are also found in North America, Neuzil said.

Neuzil added that future glaciation probably doesn’t pose a serious threat to storage sites, as most of the shale formations he’s looking at have gone through several glaciations unchanged. “Damage to waste containers, which will be surrounded by a filler material, is also not seen as a concern,” he said.

He noted that one critical criterion for a good site must be a lack of oil or natural gas that could attract future interest.

Diamonds in Earth’s oldest zircons are nothing but laboratory contamination

This image explains how synthetic diamond can be distinguished from natural diamond. -  Dobrzhinetskaya Lab, UC Riverside.
This image explains how synthetic diamond can be distinguished from natural diamond. – Dobrzhinetskaya Lab, UC Riverside.

As is well known, the Earth is about 4.6 billion years old. No rocks exist, however, that are older than about 3.8 billion years. A sedimentary rock section in the Jack Hills of western Australia, more than 3 billion years old, contains within it zircons that were eroded from rocks as old as about 4.3 billion years, making these zircons, called Jack Hills zircons, the oldest recorded geological material on the planet.

In 2007 and 2008, two research papers reported in the journal Nature that a suite of zircons from the Jack Hills included diamonds, requiring a radical revision of early Earth history. The papers posited that the diamonds formed, somehow, before the oldest zircons – that is, before 4.3 billion years ago – and then were recycled repeatedly over a period of 1.2 billion years during which they were periodically incorporated into the zircons by an unidentified process.

Now a team of three researchers, two of whom are at the University of California, Riverside, has discovered using electron microscopy that the diamonds in question are not diamonds at all but broken fragments of a diamond-polishing compound that got embedded when the zircon specimen was prepared for analysis by the authors of the Nature papers.

“The diamonds are not indigenous to the zircons,” said Harry Green, a research geophysicist and a distinguished professor of the Graduate Division at UC Riverside, who was involved in the research. “They are contamination. This, combined with the lack of diamonds in any other samples of Jack Hills zircons, strongly suggests that there are no indigenous diamonds in the Jack Hills zircons.”

Study results appear online this week in the journal Earth and Planetary Science Letters.

“It occurred to us that a long-term history of diamond recycling with intermittent trapping into zircons would likely leave some sort of microstructural record at the interface between the diamonds and zircon,” said Larissa Dobrzhinetskaya, a professional researcher in the Department of Earth Sciences at UCR and the first author of the research paper. “We reasoned that high-resolution electron microscopy of the material should be able to distinguish whether the diamonds are indeed what they have been believed to be.”

Using an intensive search with high-resolution secondary-electron imaging and transmission electron microscopy, the research team confirmed the presence of diamonds in the Jack Hills zircon samples they examined but could readily identify them as broken fragments of diamond paste that the original authors had used to polish the zircons for examination. They also observed quartz, graphite, apatite, rutile, iron oxides, feldspars and other low-pressure minerals commonly included into zircon in granitic rocks.

“In other words, they are contamination from polishing with diamond paste that was mechanically injected into silicate inclusions during polishing” Green said.

The research was supported by a grant from the National Science Foundation.

Green and Dobrzhinetskaya were joined in the research by Richard Wirth at the Helmholtz Centre Potsdam, Germany.

Dobrzhinetskaya and Green planned the research project; Dobrzhinetskaya led the project; she and Wirth did the electron microscopy.

Scientist finds topography of Eastern Seaboard muddles ancient sea level changes

The distortion of the ancient shoreline and flooding surface of the U.S. Atlantic Coastal Plain are the direct result of fluctuations in topography in the region and could have implications on understanding long-term climate change, according to a new study.

Sedimentary rocks from Virginia through Florida show marine flooding during the mid-Pliocene Epoch, which correlates to approximately 4 million years ago. Several wave-cut scarps, (rock exposures) which originally would have been horizontal, are now draped over a warped surface with up to 60 meters variation.

Nathan Simmons of Lawrence Livermore National Laboratory and colleagues from the University of Chicago, Université du Québec à Montréal, Syracuse University, Harvard University and the University of Texas at Austin modeled the active topography using mantle convection simulations that predict the amplitude and broad spatial distribution of this distortion. The results imply that dynamic topography and, to a lesser extent, glacial adjustment, account for the current architecture of the coastal plain and nearby shelf.

The results appear in the May 16 edition of Science Express, and will appear at a later date in Science Magazine,

“Our simulations of dynamic topography of the Eastern Seaboard have implications for inferences of global long-term sea-level change,” Simmons said.

The eastern coast of the United States is considered an archetypal Atlantic-type or passive-type continental margin.

“The highlight is that mantle flow is a major component in distorting the Earth’s surface over geologic time, even in so-called ‘passive’ continental margins,” Simmons said. “Reconstructing long-term global sea-level change based on stratigraphic relations must account for this effect. In other words, did the water level change or did the ground move? This could have implications on understanding very long-term climate change.”

The mantle is not a passive player in determining long-term sea level changes. Mantle flow influences surface topography, through perturbations of the dynamic topography, in a manner that varies both spatially and temporally. As a result, it is it difficult to invert for the global long-term sea level signal and, in turn, the size of the Antarctic Ice Sheet, using east coast shoreline data.

Simmons said the new results provide another powerful piece of evidence that mantle flow is intimately involved in shaping the Earth’s surface and must be considered when attempting to unravel numerous long-term Earth processes such as sea-level variations over millions of years.

Scientists say that microbial mats built 3.4-billion-year-old stromatolites

This is a rare paleosurface view of what conical stromatolites would have looked like if you snorkeled in the shallows of the reef. -  Abigail Allwood
This is a rare paleosurface view of what conical stromatolites would have looked like if you snorkeled in the shallows of the reef. – Abigail Allwood

Stromatolites are dome- or column-like sedimentary rock structures that are formed in shallow water, layer by layer, over long periods of geologic time. Now, researchers from the California Institute of Technology (Caltech) and the Jet Propulsion Laboratory (JPL) have provided evidence that some of the most ancient stromatolites on our planet were built with the help of communities of equally ancient microorganisms, a finding that “adds unexpected depth to our understanding of the earliest record of life on Earth,” notes JPL astrobiologist Abigail Allwood, a visitor in geology at Caltech.

Their research, published in a recent issue of the Proceedings of the National Academy of Sciences (PNAS), might also provide a new avenue for exploration in the search for signs of life on Mars.

“Stromatolites grow by accreting sediment in shallow water,” says John Grotzinger, the Fletcher Jones Professor of Geology at Caltech. “They get molded into these wave forms and, over time, the waves turn into discrete columns that propagate upward, like little knobs sticking up.”

Geologists have long known that the large majority of the relatively young stromatolites they study-those half a billion years old or so-have a biological origin; they’re formed with the help of layers of microbes that grow in a thin film on the seafloor.

How? The microbes’ surface is coated in a mucilaginous substance to which sediment particles rolling past get stuck. “It has a strong flypaper effect,” says Grotzinger. In addition, the microbes sprout a tangle of filaments that almost seem to grab the particles as they move along.

“The end result,” says Grotzinger, “is that wherever the mat is, sediment gets trapped.”

Thus it has become accepted that a dark band in a young stromatolite is indicative of organic material, he adds. “It’s matter left behind where there once was a mat.”

But when you look back 3.45 billion years, to the early Archean period of geologic history, things aren’t quite so simple.

“Because stromatolites from this period of time have been around longer, more geologic processing has happened,” Grotzinger says. Pushed deeper toward the center of Earth as time went by, these stromatolites were exposed to increasing, unrelenting heat. This is a problem when it comes to examining the stromatolites’ potential biological beginnings, he explains, because heat degrades organic matter. “The hydrocarbons are driven off,” he says. “What’s left behind is a residue of nothing but carbon.”

This is why there has been an ongoing debate among geologists as to whether or not the carbon found in these ancient rocks is diagnostic of life or not.

Proving the existence of life in younger rocks is fairly simple-all you have to do is extract the organic matter, and show that it came from the microorganisms. But there’s no such cut-and-dried method for analyzing the older stromatolites. “When the rocks are old and have been heated up and beaten up,” says Grotzinger, “all you have to look at is their texture and morphology.”

Which is exactly what Allwood and Grotzinger did with samples gathered at the Strelley Pool stromatolite formation in Western Australia. The samples, says Grotzinger, were “incredibly well preserved.” Dark lines of what was potentially organic matter were “clearly associated with the lamination, just like we see in younger rocks. That sort of relationship would be hard to explain without a biological mechanism.”

“We already knew from our earlier work that we had an assemblage of stromatolites that was most plausibly interpreted as a microbial reef built by Early Archean microorganisms,” adds Allwood, “but direct evidence of actual microorganisms was lacking in these ancient, altered rocks. There were no microfossils, no organic material, not even any of the microtextural hallmarks typically associated with microbially mediated sedimentary rocks.”

So Allwood set about trying to find other types of evidence to test the biological hypothesis. To do so, she looked at what she calls the “microscale textures and fabrics in the rocks, patterns of textural variation through the stromatolites and-importantly-organic layers that looked like actual fossilized organic remnants of microbial mats within the stromatolites.”

What she saw were “discrete, matlike layers of organic material that contoured the stromatolites from edge to edge, following steep slopes and continuing along low areas without thickening.” She also found pieces of microbial mat incorporated into storm deposits, which disproved the idea that the organic material had been introduced into the rock more recently, rather than being laid down with the original sediment. “In addition,” Allwood notes, “Raman spectroscopy showed that the organics had been ‘cooked’ to the same burial temperature as the host rock, again indicating the organics are not young contaminants.”

Allwood says she, Grotzinger, and their team have collected enough evidence that it’s no longer any “great leap” to accept these stromatolites as biological in origin. “I think the more we dig at these stromatolites, the more evidence we’ll find of Early Archean life and the nature of Earth’s early ecosystems,” she says.

That’s no small feat, since it’s been difficult to prove that life existed at all that far back in the geologic record. “Recently there has been increasing but still indirect evidence suggesting life existed back then, but direct evidence of microorganisms, at the microscale, remained elusive due to poor preservation of the rocks,” Allwood notes. “I think most people probably thought that these Early Archean rocks were too poorly preserved to yield such information.”

The implications of the findings don’t stop at life on Earth.

“One of my motivations for understanding stromatolites,” Allwood says, “is the knowledge that if microbial communities once flourished on Mars, of all the traces they might leave in the rock record for us to discover, stromatolite and microbial reefs are arguably the most easily preserved and readily detected. Moreover, they’re particularly likely to form in evaporative, mineral-precipitating settings such as those that have been identified on Mars. But to be able to interpret stromatolitic structures, we need a much more detailed understanding of how they form.”

Low Oxygen and Molybdenum Levels in Ancient Oceans Delayed Evolution of Life by Two Billion Years


UCR-led study tracked biogeochemical signatures preserved in ancient sedimentary rocks to establish nature and timing of oxygenation of Earth’s atmosphere

A deficiency of oxygen and the heavy metal molybdenum in the ancient deep ocean may have delayed the evolution of animal life on Earth by nearly two billion years, a study led by UC Riverside biogeochemists has found.

The researchers arrived at their result by tracking molybdenum in black shales, which are a kind of sedimentary rock rich in organic matter and usually found in the deep ocean. Molybdenum is a key micronutrient for life and serves as a proxy for oceanic and atmospheric oxygen amounts.

Study results appear in the March 27 issue of Nature.

Following the initial rise of oxygen in the Earth’s atmosphere 2.4 billion years ago, oxygen was transferred to the surface ocean to support oxygen-demanding microorganims. Yet the diversity of these single-celled life forms remained low, and their multicellular descendants, the animals, did not appear until about 600 million years ago, explained Timothy Lyons, a professor of biogeochemistry in the Department of Earth Sciences and one of the study’s authors.

Suspecting that deficiencies in oxygen and molybdenum might explain this evolutionary lag, Lyons and his colleagues measured abundances of molybdenum in ancient marine sediments over time to estimate how much of the metal had been dissolved in the seawater in which the sediments formed.

The researchers found significant, firsthand evidence for a molybdenum-depleted ocean relative to the high levels measured in modern, oxygen-rich seawater.

“These molybdenum depletions may have retarded the development of complex life such as animals for almost two billion years of Earth history,” Lyons said. “The amount of molybdenum in the ocean probably played a major role in the development of early life. As in the case of iron today, molybdenum can be thought of as a life-affirming micronutrient that regulates the biological cycling of nitrogen in the ocean.

“At the same time, molybdenum’s low abundance in the early ocean tracks the global extent of oxygen-poor seawater and implies that the amount of oxygen in the atmosphere was still low.

“Knowing the amount of oxygen in the early ocean is important for many reasons, including a refined understanding of how and when appreciable oxygen first began to accumulate in the atmosphere,” Lyons said. “These steps in oxygenation are what gave rise ultimately to the first animals almost 600 million years ago – just the last tenth or so of Earth history.”

Earth’s oxygenation

For animal life to commence, survive and eventually expand on Earth, a threshold amount of oxygen – estimated to be on the order of 1 to 10 percent of present atmospheric levels of oxygen – was needed.

Past research has shown that Earth’s oxygenation occurred in two major steps:

The first step, around 2.4 billion years ago, took place as the ocean transitioned to a state where only the surface ocean was oxygenated by photosynthesizing bacteria, while the deep ocean was relatively oxygen-free.

The second step, around 600 million years ago, marked the occasion when the entire ocean became fully oxygenated through a process not yet fully understood.

“We wanted to know what the state of the ocean was between the two steps,” said Clinton Scott, a graduate student working in Lyons’s lab and the first author of the research paper. “By tracking molybdenum in shales rich in organic matter, we found the deep ocean remained oxygen- and molybdenum-deficient after the first step. This condition may have had a negative impact on the evolution of early eukaryotes, our single-celled ancestors. The molybdenum record also tells us that the deep ocean was already fully oxygenated by around 550 million years ago.”

According to Scott, the timing of the oxygenation steps suggests that significant events in Earth history are related. Scientists have long speculated that the evolution of the first animals was linked somehow to the so-called Snowball Earth hypothesis, which posits that the Earth was covered from pole to pole in a thick sheet of ice for millions of years at a time. “The second oxygenation step took place not long after the last Snowball Earth episode ended around 600 million years ago,” Scott said. “So one question is: Did this global glaciation play a role in the increasing abundance of oxygen which, in turn, enabled the evolution of animals?”

Scott and Lyons were joined in the research by A. Bekker of the Carnegie Institution of Washington, DC; Y. Shen of the Université du Québec à Montréal, Canada; S.W. Poulton of Newcastle University, Newcastle upon Tyne, United Kingdom; X. Chu of the Chinese Academy of Sciences, Beijing, China; and A.D. Anbar of Arizona State University, Tempe, Ariz.

The research was supported by grants from the U.S. National Science Foundation Division of Earth Sciences and the NASA Astrobiology Institute.

More about molybdenum as a proxy for ocean chemistry

Molybdenum, a metal abundant in the ocean today but less so at times in the past, is an excellent tracer of ancient chemistry for two reasons. First, the primary source of molybdenum to the ocean is oxidative weathering of continental crust, requiring oxygen in the atmosphere. Second, molybdenum is removed primarily in marine sediments where oxygen is absent and sulfide is abundant. Thus the enrichment of molybdenum in ancient organic-rich shales requires oxygen in the atmosphere but high sulfur and very low or no oxygen in the deep ocean. This combination is relatively rare today but may have been common when oxygen was less abundant in the earlier atmosphere.

When oxygen is available in the atmosphere, the amount of dissolved molybdenum in seawater is determined by the extent of hydrogen-sulfide-containing sediments and bottom waters (the colder, more isolated, lowermost layer of ocean water). Where sulfidic environments are widespread, the pool of molybdenum remaining in seawater is small, growing as the sulfidic environments shrink. The amount of molybdenum in the seawater is reflected in the magnitude of molybdenum enrichment in shales deposited in the deep ocean.

The UCR-led team of researchers estimated the size of the oceanic reservoir, and thus the extent of sulfidic bottom waters and sediments, based on the concentration of molybdenum in ancient black shales. They did so by dissolving the samples in a cocktail of acids and analyzing the dissolved rock for concentration using a mass spectrometer. The amount of this metal in the shales tracks the oxygen state of the early ocean and atmosphere and also points to the varying abundance of this essential ingredient of life. Molybdenum limitations may have delayed the development of eukaryotes, including the first animals, our earliest multicellular cousins.

Hot springs microbes hold key to dating sedimentary rocks, researchers say

Mammoth Hotsprings in Yellowstone National Park
Mammoth Hotsprings in Yellowstone National Park

Scientists studying microbial communities and the growth of sedimentary rock at Mammoth Hot Springs in Yellowstone National Park have made a surprising discovery about the geological record of life and the environment.

Their discovery could affect how certain sequences of sedimentary rock are dated, and how scientists might search for evidence of life on other planets.

“We found microbes change the rate at which calcium carbonate precipitates, and that rate controls the chemistry and shape of calcium carbonate crystals,” said Bruce Fouke, a professor of geology and of molecular and cellular biology at the University of Illinois.

In fact, the precipitation rate can more than double when microbes are present, Fouke and his colleagues report in a paper accepted for publication in the Geological Society of America Bulletin.

The researchers’ findings imply changes in calcium carbonate mineralization rates in the rock record may have resulted from changes in local microbial biomass concentrations throughout geologic history.

A form of sedimentary rock, calcium carbonate is the most abundant mineral precipitated on the surface of Earth, and a great recorder of life.

“As calcium carbonate is deposited, it leaves a chemical fingerprint of the animals and environment, the plants and bacteria that were there,” said Fouke, who also is affiliated with the university’s Institute for Genomic Biology.

The extent to which microorganisms influence calcium carbonate precipitation has been one of the most controversial issues in the field of carbonate sedimentology and geochemistry. Separating biologically precipitated calcium carbonate from non-biologically precipitated calcium carbonate is difficult.

Fouke’s research team has spent 10 years quantifying the physical, chemical and biological aspects of the hot springs environment. The last step in deciphering the calcium carbonate record was performing an elaborate field experiment, which drew water from a hot springs vent and compared deposition rates with and without microbes being present.

“Angel Terrace at Mammoth Hot Springs in Yellowstone National Park is an ideal, natural laboratory because of the high precipitation rates and the abundance of microbes,” Fouke said. “Calcium carbonate grows so fast – millimeters per day – we can examine the interaction between microorganisms and the calcium-carbonate precipitation process.”

The researchers found that the rate of precipitation drops drastically – sometimes by more than half – when microbes are not present.

“So one of the fingerprints of calcium carbonate deposition that will tell us for sure if there were microbes present at the time it formed is the rate at which it formed,” Fouke said. “And, within the environmental and ecological context of the rock being studied, we can now use chemistry to fingerprint the precipitation rate.”

In a second paper, to appear in the Journal of Sedimentary Research, Fouke and colleagues show how the calcium carbonate record in a spring’s primary flow path can be used to reconstruct the pH, temperature and flux of ancient hot springs environments. The researchers also show how patterns in calcium carbonate crystallization can be used to differentiate signatures of life from those caused by environmental change.

“This means we can go into the rock record, on Earth or other planets, and determine if calcium carbonate deposits were associated with microbial life,” Fouke said.

As waters clear, scientists seek to end a muddy debate

Schieber uses a camera to track the growth and movement of mud formations - Photo by: Chris Meyer
Schieber uses a camera to track the growth and movement of mud formations – Photo by: Chris Meyer

Geologists have long thought muds will only settle when waters are quiet, but new research by Indiana University Bloomington and Massachusetts Institute of Technology geologists shows muds will accumulate even when currents move swiftly. Their findings appear in this week’s Science.

This may seem a trifling matter at first, but understanding the deposition of mud could significantly impact a number of public and private endeavors, from harbor and canal engineering to oil reservoir management and fossil fuel prospecting.

“Mudstones make up two-thirds of the sedimentary geological record,” said IU Bloomington geologist Juergen Schieber, who led the study. “One thing we are very certain of is that our findings will influence how geologists and paleontologists reconstruct Earth’s past.”

Previously geologists had thought that constant, rapid water flow prevented mud’s constituents — silts and clays — from coalescing and gathering at the bottoms of rivers, lakes and oceans. This has led to a bias, Schieber explains, that wherever mudstones are encountered in the sedimentary rock record, they are generally interpreted as quiet water deposits.

“But we suspected this did not have to be the case,” Schieber said. “All you have to do is look around. After the creek on our university’s campus floods, you can see ripples on the sidewalks once the waters have subsided. Closely examined, these ripples consist of mud. Sedimentary geologists have assumed up until now that only sand can form ripples and that mud particles are too small and settle too slowly to do the same thing. We just needed to demonstrate it that it can actually happen under controlled conditions.”

Schieber and IU graduate student Kevin Thaisen used a specially designed “mud flume” to simulate mud deposition in natural flows. The oval-shaped apparatus resembles a race track. A motorized paddle belt keeps water moving in one direction at a pre-determined speed, say, 26 centimeters per second (about 0.6 miles per hour). The concentration of dispersed sediment, temperature, salinity, and a dozen other parameters can be controlled. M.I.T. veteran sedimentologist John Southard provided advice on the construction and operation of the mud flume used in the experiments.

For their experiments, the scientists used calcium montmorillonite and kaolinite, extremely fine clays that in dry form have the feel of facial powder. Most geologists would have predicted that these tiny mineral grains could not settle easily from rapidly moving water, but the flume experiments showed that mud was traveling on the bottom of the flume after a short time period. Experiments with natural lake muds showed the same results.

“We found that mud beds accumulate at flow velocities that are much higher than what anyone would have expected,” said Schieber, who, because of the white color of the clay suspensions, calls this ongoing work the “sedimentology of milk.”

The mud accumulates slowly at first, in the form of heart- or arrowhead-shaped ripples that point upstream. These ripples slowly move with the current while maintaining their overall shapes.

Understanding how and when muds deposit will aid engineers who build harbors and canals, Schieber says, by providing them with new information about the rates at which mud can accumulate from turbid waters. Taking into account local conditions, engineers can build waterways in a way that truly minimizes mud deposition by optimizing tidal and wave-driven water flow. Furthermore, Schieber explains, the knowledge that muds can deposit from moving waters could expand the possible places where oil companies prospect for oil and gas. Organic matter and muds are both sticky and are often found together.

“If anything, when organic matter is present in addition to mud, it enhances mud deposition from fast moving currents,” he said.

The finding feels like something of a vindication, Schieber says. He and his colleagues have (genially) argued about whether muds could deposit from rapidly flowing water. Schieber had posited the possibility after noting an apparent oddity in the sedimentary rock record.

“In many ancient mudstones, you see not only deposition, but also erosion and rapid re-deposition of mud — all in the same place,” Schieber said. “The erosive features are at odds with the notion that the waters must have been still all or most of the time. We needed a better explanation.”

This research was supported by a grant from the National Science Foundation.

Geologist discovers Martian mineral

Geology professor Ron Peterson discovered natural crystals in a frozen BC pond similar to ones that he grew in his garage -- and are also believed to exist on Mars. - Photo Courtesy: Ron Peterson
Geology professor Ron Peterson discovered natural crystals in a frozen BC pond similar to ones that he grew in his garage — and are also believed to exist on Mars. – Photo Courtesy: Ron Peterson

A Queen’s University researcher’s surprising discovery – made first in his garage and later verified through field work – has resulted in the naming of a new mineral species that may exist on Mars, and has caught the attention of the NASA space program.

Geologist Ron Peterson’s findings will be reported in the October issue of the journal, American Mineralogist. Dr. Peterson, who was invited to Houston last fall to present his original findings at the Johnson Space Center, continues to work with NASA scientists on Mars research.

The new mineral, meridianiite, is unusual because it is a planetary mineral and also thought to exist on the moons of Jupiter.

Also on the research team are Bruce Madu from the B.C. Ministry of Energy, Mines, and Petroleum Resources, Queen’s Chemistry Professor Herb Shurvell, and high school student Will Nelson, from Ascroft, B.C.

The Queen’s discovery was inspired by information sent back from Mars by the Mars Exploration Rover (MER), Opportunity, indicating that magnesium sulfate is present on that planet’s surface. The rover also sent back photographs of voids in rocks that are thought to have originally contained crystals.

This supports the team’s theory that regions of Mars were once covered with water, which later froze and then evaporated, leaving a residue of crystal molds in the sediment.

Based on these observations, in the winter of 2005, Dr. Peterson left a solution of drugstore epsom salts (hydrated magnesium sulfate) to crystallize in his unheated garage for several days. He then rushed the frozen crystals to a Queen’s chemistry lab, where experiments showed them to be an unusual form of magnesium sulfate that displayed some of the same properties reported earlier by Mars rovers.

Dr. Peterson wondered whether the same mineral might be found on Earth. In the fall of 2006 he located some ponds near Ashcroft in the Okanagan Valley of B.C., from which magnesium sulfate had once been mined. He then enlisted the help of a local high-school chemistry student to send him mineral samples from the ponds, by mail, throughout the fall.

In February 2007 Dr. Peterson visited the frozen ponds himself, and brought back crystals in a cooler packed with dry ice. These natural crystals were put through a series of tests, and in June meridianiite was approved as a new valid mineral species by the Commission on New Mineral names and Mineral Nomenclature of the International Mineralogical Association.

-The name was chosen to reflect the locality on Mars where a rover had observed crystal molds in sedimentary rock that are thought to be caused by minerals that have since dehydrated or dissolved,- says Dr. Peterson. -Observations obtained by using the rover wheels to dig trenches into the Martian soil show that magnesium sulfate minerals have been deposited below the surface.-

Between 20 and 30 new minerals are identified each year, the researcher notes, but -these often involve rare elements.- Meridianiite, on the other hand, is formed from the common materials magnesium, sulfate and water.

A geologist who normally studies mine waste, Dr. Peterson admits he has been a -space geek- since childhood, and says that working on this project has been exciting. -It began with a moment of insight – based on my previous geological experience – and now I have the chance to collaborate with experts from around the world who are studying the geology of the Martian surface.-