It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, June 07, 2023
GEOLOGY
Scientists discover ‘lost world’ of early ancestors in billion-year-old rocks
IMAGE: ARTIST’S IMAGINATION OF TWO PRIMORDIAL EUKARYOTIC ORGANISMS OF THE ‘PROTOSTEROL BIOTA’ ON THE OCEAN FLOOR. BASED ON MOLECULAR FOSSILS, ORGANISMS OF THE PROTOSTEROL BIOTA LIVED IN THE OCEANS ABOUT 1.6 TO 1.0 BILLION YEARS AGO AND ARE OUR EARLIEST KNOWN ANCESTORS. ORCHESTRATED IN MIDJOURNEY BY TA 2023.view more
CREDIT: CREDIT: ORCHESTRATED IN MIDJOURNEY BY TA 2023
The discovery of a “lost world” of ancient organisms that lived in Earth’s waterways at least 1.6 billion years ago could change our understanding of our earliest ancestors.
Known as the ‘Protosterol Biota’, these microscopic creatures are part of a family of organisms called eukaryotes. Eukaryotes have a complex cell structure that includes mitochondria, known as the “powerhouse” of the cell, and a nucleus that acts as the “control and information centre”.
Modern forms of eukaryotes that inhabit Earth today include fungi, plants, animals and single-celled organisms such as amoebae. Humans and all other nucleated creatures can trace their ancestral lineage back to the Last Eukaryotic Common Ancestor (LECA). LECA lived more than 1.2 billion years ago.
The discovery of the Protosterol Biota, published in Nature, was made by researchers from The Australian National University (ANU). According to the researchers, these organisms could have been the first predators on Earth.
These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth’s history. The researchers say the Protosterol Biota lived at least one billion years before any animal or plant emerged.
“Molecular remains of the Protosterol Biota detected in 1.6-billion-year-old rocks appear to be the oldest remnants of our own lineage – they lived even before LECA. These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth’s history,” Dr Benjamin Nettersheim, who completed his PhD at ANU and is now based at the University of Bremen in Germany, said.
“Modern forms of eukaryotes are so powerful and dominant today that researchers thought they should have conquered the ancient oceans on Earth more than a billion years ago.
“Scientists have long searched for fossilised evidence of these early eukaryotes, but their physical remains are extremely scarce. Earth’s ancient oceans rather appeared to be largely a bacterial broth.
“One of the greatest puzzles of early evolution scientists have been trying to answer is: why didn’t our highly capable eukaryotic ancestors come to dominate the world’s ancient waterways? Where were they hiding?
“Our study flips this theory on its head. We show that the Protosterol Biota were hiding in plain sight and were in fact abundant in the world’s ancient oceans and lakes all along. Scientists just didn’t know how to look for them – until now.”
Professor Jochen Brocks from ANU, who made the discovery with Dr Nettersheim, said the Protosterol Biota were certainly more complex than bacteria and presumably larger, although it’s unknown what they looked like.
“We believe they may have been the first predators on Earth, hunting and devouring bacteria,” Professor Brocks said.
According to Professor Brocks, these creatures thrived from about 1.6 billion years ago up until about 800 million years ago.
The end of this period in Earth’s evolutionary timeline is known as the ‘Tonian Transformation’, when more advanced nucleated organisms, such as fungi and algae, started to flourish. But exactly when the Protosterol Biota went extinct is unknown.
“The Tonian Transformation is one of the most profound ecological turning points in our planet’s history,” Professor Brocks said.
“Just as the dinosaurs had to go extinct so that our mammal ancestors could become large and abundant, perhaps the Protosterol Biota had to disappear a billion years earlier to make space for modern eukaryotes.”
To make the discovery, the researchers studied fossil fat molecules found inside a 1.6-billion-year-old rock that had formed at the bottom of the ocean near what is now Australia’s Northern Territory. The molecules possessed a primordial chemical structure that hinted at the existence of early complex creatures that evolved before LECA and had since gone extinct.
“Without these molecules, we would never have known that the Protosterol Biota existed. Early oceans largely appeared to be a bacterial world, but our new discovery shows that this probably wasn’t the case,” Dr Nettersheim said.
Professor Brocks said: “Scientists had overlooked these molecules for four decades because they do not conform to typical molecular search images.”
“But once we knew what we were looking for, we discovered that dozens of other rocks, taken from billion-year-old waterways across the world, were also oozing with similar fossil molecules.”
Dr Nettersheim completed the analysis as part of his PhD at ANU before accepting a position at the University of Bremen. This work involved scientists from Australia, France, Germany and the United States.
MARUM - CENTER FOR MARINE ENVIRONMENTAL SCIENCES, UNIVERSITY OF BREMEN
IMAGE: BENJAMIN NETTERSHEIM, ONE OF THE LEAD AUTHORS OF THE STUDY, EXAMINES ULTRA-HIGH-RESOLUTION ELEMENTAL AND MOLECULAR MAPS OF 1.64 BILLION YEARS-OLD ROCK SAMPLES ANALYZED AT THE GEOBIOMOLECULAR IMAGING LABORATORY AT MARUM. . PHOTO: MARUM – CENTER FOR MARINE ENVIRONMENTAL SCIENCES, UNIVERSITY OF BREMEN; V. DIEKAMPview more
CREDIT: . PHOTO: MARUM – CENTER FOR MARINE ENVIRONMENTAL SCIENCES, UNIVERSITY OF BREMEN; V. DIEKAMP
The newly discovered record of so-called protosteroids was shown to be surprisingly abundant throughout Earth´s Middle Ages. The primordial molecules were produced at an earlier stage of eukaryotic complexity – extending the current record of fossil steroids beyond 800 and up to 1600 million years ago. Eukaryotes is the term for a kingdom of life including all animals, plants and algae and set apart from bacteria by having a complex cell structure that includes a nucleus, as well as a more complex molecular machinery. “The highlight of this finding is not just the extension of the current molecular record of eukaryotes,” says Christian Hallmann one of the participating scientists from the German Research Center for Geosciences (GFZ) in Potsdam. “Given that the last common ancestor of all modern eukaryotes, including us humans, was likely capable of producing ‘regular’ modern sterols, chances are high that the eukaryotes responsible for these rare signatures belonged to the stem of the phylogenetic tree”.
This “stem” represents the common ancestral lineage that was a precursor to all still living branches of eukaryotes. Its representatives are long extinct, yet details of their nature may shed more light on the conditions surrounding the evolution of complex life. Although more research is needed to evaluate what percentage of protosteroids may have had a rare bacterial source, the discovery of these new molecules not only reconciles the geological record of traditional fossils with that of fossil lipid molecules, but yields a rare and unprecedented glimpse of a lost world of ancient life. The competitive demise of stem group eukaryotes, marked by the first appearance of modern fossil steroids some 800 million years ago, may reflect one of the most incisive events in the evolution of increasingly complex life.
"Almost all eukaryotes biosynthesize steroids, such as cholesterol that is produced by humans and most other animals” adds Benjamin Nettersheim from MARUM, University of Bremen, who shares first authorship of the study with Jochen Brocks from the Australian National University (ANU) – “due to potentially adverse health effects of elevated cholesterol levels in humans, cholesterol doesn’t have the best reputation from a medical perspective. However, these lipid molecules are integral parts of eukaryotic cell membranes where they aid in a variety of physiological functions. By searching for fossilized steroids in ancient rocks, we can trace the evolution of increasingly complex life”.
Nobel laureate Konrad Bloch had already speculated about such a biomarker in an essay almost 30 years ago. Bloch suggested that short-lived intermediates in the modern biosynthesis of steroids may not always have been intermediates. He believed that lipid biosynthesis evolved in parallel with changing environmental conditions throughout Earth history. In contrast to Bloch, who did not believe that these ancient intermediates could ever be found, Nettersheim started searching for protosteroids in ancient rocks that were deposited at a time when those intermediates could actually have been the final product.
But how to find such molecules in ancient rocks? “We employed a combination of techniques to first convert various modern steroids to their fossilized equivalent; otherwise, we wouldn’t have even known what to look for,” says Jochen Brocks. Scientists had overlooked these molecules for decades because they do not conform to typical molecular search images. “Once we knew our target, we discovered that dozens of other rocks, taken from billion-year-old waterways across the world, were oozing with similar fossil molecules.”
The oldest samples with the biomarker are from the Barney Creek Formation in Australia and are 1.64 billion years old. The rock record of the next 800 million years only yields fossil molecules of primordial eukaryotes before molecular signatures of modern eukaryotes first appear in the Tonian period. According to Nettersheim “the Tonian Transformation emerges as one of the most profound ecological turning points in our planet´s history“. Hallmann adds that “both primordial stem groups and modern eukaryotic representatives such as red algae may have lived side by side for many hundreds of millions of years”. During this time, however, the Earth's atmosphere became increasingly enriched with oxygen – a metabolic product of cyanobacteria and of the first eukaryotic algae – that would have been toxic to many other organisms. Later, global "Snowball Earth” glaciations occurred and the protosterol communities largely died out. The last common ancestor of all living eukaryotes may have lived 1.2 to 1.8 billion years ago. Its descendants were likely better able to survive heat and cold as well as UV radiation and displaced their primordial relatives.
“Earth was a microbial world for much of its history and left few traces,” Nettersheim concludes. Research at ANU, MARUM and GFZ continues to pursue tracing the roots of our existence – the discovery of protosterols now brings us one step closer to understanding how our earliest ancestors lived and evolved. Shooting at the ancient rocks with a laser coupled to an ultra-high resolution mass spectrometer in MARUM's globally unique Geobiomolecular Imaging Laboratory, Dr. Nettersheim and his international collaborators aim at zooming into the cradle of eukaryotic life in unprecedented resolution to further improve our understanding of our early ancestors in the future.
Artist’s imagination of an assemblage of primordial eukaryotic organisms of the ‘Protosterol Biota’ inhabiting a bacterial mat on the ocean floor. Based on molecular fossils, organisms of the Protosterol Biota lived in the oceans about 1.6 to 1.0 billion years ago and are our earliest known ancestors. Orchestrated in MidJourney by TA 2023
CREDIT
Orchestrated in MidJourney by TA 2023
Participating Institutions:
Research School of Earth Sciences, The Australian National University, Canberra, Australia
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
Faculty of Geosciences, University of Bremen, Bremen, Germany
Université de Strasbourg, CNRS, Institut de Chimie de Strasbourg, Strasbourg, France
Northern Territory Geological Survey, Darwin, Australia
German Research Center for Geosciences (GFZ), Potsdam, Germany
MARUM produces fundamental scientific knowledge about the role of the ocean and the ocean floor in the total Earth system. The dynamics of the ocean and the ocean floor significantly impact the entire Earth system through the interaction of geological, physical, biological and chemical processes. These influence both the climate and the global carbon cycle, and create unique biological systems. MARUM is committed to fundamental and unbiased research in the interests of society and the marine environment, and in accordance with the Sustainable Development Goals of the United Nations. It publishes its quality-assured scientific data and makes it publicly available. MARUM informs the public about new discoveries in the marine environment and provides practical knowledge through its dialogue with society. MARUM cooperates with commercial and industrial partners in accordance with its goal of protecting the marine environment.
GFZ GEOFORSCHUNGSZENTRUM POTSDAM, HELMHOLTZ CENTRE
IMAGE: ARTIST’S IMAGINATION OF AN ASSEMBLAGE OF PRIMORDIAL EUKARYOTIC ORGANISMS OF THE ‘PROTOSTEROL BIOTA’ INHABITING A BACTERIAL MAT ON THE OCEAN FLOOR. BASED ON MOLECULAR FOSSILS, ORGANISMS OF THE PROTOSTEROL BIOTA LIVED IN THE OCEANS ABOUT 1.6 TO 1.0 BILLION YEARS AGO AND ARE OUR EARLIEST KNOWN ANCESTORS (CREDIT: ORCHESTRATED IN MIDJOURNEY BY TA 2023).view more
CREDIT: ORCHESTRATED IN MIDJOURNEY BY TA 2023
Newly discovered biomarker signatures point to a whole range of previously unknown organisms that dominated complex life on Earth about a billion years ago. They differed from complex eukaryotic life as we know it, such as animals, plants and algae in their cell structure and likely metabolism, which was adapted to a world that had far less oxygen in the atmosphere than today. An international team of researchers, including GFZ geochemist Christian Hallmann, now reports on this breakthrough for the field of evolutionary geobiology in the journal Nature.
The previously unknown “protosteroids” were shown to be surprisingly abundant throughout Earth´s Middle Ages. The primordial molecules were produced at an earlier stage of eukaryotic complexity — extending the current record of fossil steroids beyond 800 and up to 1,600 million years ago. Eukaryotes is the term for a kingdom of life including all animals, plants and algae and set apart from bacteria by having a complex cell structure that includes a nucleus, as well as a more complex molecular machinery. “The highlight of this finding is not just the extension of the current molecular record of eukaryotes,” Hallmann says: “Given that the last common ancestor of all modern eukaryotes, including us humans, was likely capable of producing ‘regular’ modern sterols, chances are high that the eukaryotes responsible for these rare signatures belonged to the stem of the phylogenetic tree”.
Unprecedented glimpse of a lost world
This “stem” represents the common ancestral lineage that was a precursor to all still living branches of eukaryotes. Its representatives are long extinct, yet details of their nature may shed more light on the conditions surrounding the evolution of complex life. Although more research is needed to evaluate what percentage of protosteroids may have had a rare bacterial source, the discovery of these new molecules not only reconciles the geological record of traditional fossils with that of fossil lipid molecules, but yields a rare and unprecedented glimpse of a lost world of ancient life. The competitive demise of stem group eukaryotes, marked by the first appearance of modern fossil steroids some 800 Million years ago, may reflect one of the most incisive events in the evolution of increasingly complex life.
"Almost all eukaryotes biosynthesise steroids, such as cholesterol that is produced by humans and most other animals” adds Benjamin Nettersheim from the University of Bremen, first author of the study—“due to potentially adverse health effects of elevated cholesterol levels in humans, cholesterol doesn’t have the best reputation from a medical perspective. However, these lipid molecules are integral parts of eukaryotic cell membranes where they aid in a variety of physiological functions. By searching for fossilised steroids in ancient rocks, we can trace the evolution of increasingly complex life”.
What the Nobel laureate thaught impossible...
Nobel laureate Konrad Bloch had already speculated about such a biomarker in an essay almost 30 years ago. Bloch suggested that short-lived intermediates in the modern biosynthesis of steroids may not always have been intermediates. He believed that lipid biosynthesis evolved in parallel with changing environmental conditions throughout Earth history. In contrast to Bloch, who did not believe that these ancient intermediates could ever be found, Nettersheim started searching for protosteroids in ancient rocks that were deposited at a time when those intermediates could actually have been the final product.
But how to find such molecules in ancient rocks? “We employed a combination of techniques to first convert various modern steroids to their fossilised equivalent; otherwise we wouldn’t have even known what to look for,” says Jochen Brocks, professor at the Australian National University who shares the first-authorship of the new study with Nettersheim. Scientists had overlooked these molecules for decades because they do not conform to typical molecular search images. “Once we knew our target, we discovered that dozens of other rocks, taken from billion-year-old waterways across the world, were oozing with similar fossil molecules.”
The oldest samples with the biomarker are from the Barney Creek Formation in Australia and are 1.64 billion years old. The rock record of the next 800 Million years only yields fossil molecules of primordial eukaryotes before molecular signatures of modern eukaryotes first appear in the Tonian period. According to Nettersheim “the Tonian Transformation emerges as one of the most profound ecological turning points in our planet’s history“. Hallmann adds that “both primordial stem groups and modern eukaryotic representatives such as red algae may have lived side by side for many hundreds of millions of years”. During this time, however, the Earth's atmosphere became increasingly enriched with oxygen — a metabolic product of cyanobacteria and of the first eukaryotic algae that would have been toxic to many other organisms. Later, global "Snowball Earth” glaciations occurred and the protosterol communities largely died out. The last common ancestor of all living eukaryotes may have lived 1.2 to 1.8 billion years ago. Its descendants were likely better able to survive heat and cold as well as UV radiation and displaced their primordial relatives.
Since all stem group eukaryotes are long extinct, we will never know for certain how most of our early relatives looked like, but artistic efforts have created tentative visualisations (see pictures attached), while the primordial steroids may eventually shed more light on their biochemistry and lifestyle. “Earth was a microbial world for much of its history and left few traces.” Nettersheim concludes. Research at ANU, MARUM and GFZ continues to pursue tracing the roots of our existence — the discovery of protosterols now brings us one step closer to understanding how our earliest ancestors lived and evolved.
IMAGE: UTAH STATE UNIVERSITY GEOSCIENTIST HEATHER UPIN COLLECTS A MICROBIAL SAMPLE FROM AGUAS CALIENTAS PINAYA IN PERU’S SOUTHERN ANDES. SHE AND USU COLLEAGUE DENNIS NEWELL PUBLISHED FINDINGS ABOUT MICROBIAL DIVERSITY IN PERUVIAN HOT SPRINGS.view more
CREDIT: USU/DENNIS NEWELL
LOGAN, UTAH, USA -- South America’s Andes Mountains, the world’s longest mountain range and home to some of the planet’s highest peaks, feature thousands of hot springs. Driven by plate tectonics and fueled by hot rock and fluids, these thermal discharges vary widely in geochemistry and microbial diversity.
Utah State University geoscientists, along with colleagues from Montana State University, examined 14 hot springs within the southern Andes in Peru and discovered microbial community composition is distinctly different in two tectonic settings. Dennis Newell, associate professor in USU’s Department of Geosciences, and recent USU graduate Heather Upin, MS 2020, report findings in the April 11 online issue of Nature’sCommunications Earth & Environment. Their research is supported by the National Science Foundation and the Geological Society of America.
“We know tectonic processes control hot spring temperature and geochemistry, yet how this, in turn, shapes microbial community composition is poorly understood,” says Newell, USU Geosciences graduate director.
The scientists collected geochemical and 16S ribosomal RNA gene sequencing data from hot springs in regions with contrasting styles of subduction — flat-slab and back-arc — and noted similarities in pH but found differences in geochemistry and microbiology.
“Flat-slab hot springs were chemically heterogeneous, had modest surface temperatures and were dominated by members of the metabolically diverse phylum Proteobacteria,” Newell says.
In contrast, the back-arc hot springs were more geochemically homogenous, had hotter water, exhibited high concentrations of dissolved metals and gases, and were home to heat-loving archaeal and bacterial organisms.
“These results tell us tectonics matter when it comes microbial community make-up, but little research has been conducted around the world to demonstrate this,” Newell says.
Further investigation, with efficient genomic research, at sites around the globe could reveal how microbes have evolved in tectonically diverse environments, he says.
IMAGE: UTAH STATE UNIVERSITY GEOCHEMIST DENNIS NEWELL COLLECTS DATA FROM A SPRING ALONG THE CANTWELL SEGMENT OF ALASKA’S DENALI FAULT. HE AND COLLEAGUES PUBLISHED FINDINGS IN THE JOURNAL ‘GEOLOGY,’ CITING EVIDENCE OF MANTLE-TO-CRUST CONNECTIONS THAT INCREASE THE POSSIBILITY OF A FUTURE MAJOR EARTHQUAKE.view more
CREDIT: JEFF BENOWITZ
LOGAN, UTAH, USA -- The 1,200-mile-long Denali Fault stretches in an upward arc from southwestern Alaska and the Bering Sea eastward to western Canada’s Yukon Territory and British Columbia. The long-lived and active strike-slip fault system, which slices through Denali National Park and Preserve, is responsible for the formation of the Alaska Range.
“It’s a big, sweeping fault and the source of a magnitude 7.9 earthquake in 2002, that ruptured more than 200 miles of the Denali Fault, along with the Totschunda Fault to the east, causing significant damage to remote villages and central Alaska’s infrastructure,” says Utah State University geochemist Dennis Newell.
Understanding the restless fault’s mantle-to-crust connections provides critical information for understanding the lithospheric-scale fault’s seismic cycle, says Newell, associate professor in USU’s Department of Geosciences. He and colleagues Jeff Benowitz, an Alaska-based geochronologist, Sean Regan of the University of Alaska Fairbanks, and doctoral candidate Coleman Hiett of USU, collected and analyzed helium and carbon isotopic data from springs along a nearly 250-mile segment of the fault and published their findings, “Roadblocks and Speed Limits: Mantle-to-Surface Volatile Flux in the Lithospheric Scale Denali Fault, Alaska,” in the June 1, 2023 print issue of the journal Geology.
The research was funded by a one-year National Science Foundation Early-Concept Grant for Exploratory Research (EAGER) awarded to Newell and Regan in 2020.
“Active strike-slip faults like Denali have three-dimensional geometries with possible deep conduit connections below the Earth’s surface,” Newell says. “But we don’t know much about how and if these connections are maintained.”
To examine these possible deep connections, Newell and Regan sampled 12 springs along the Denali and Totschunda Faults, by way of helicopter and on foot, to the remote, mountainous regions of Alaska’s interior.
“Helium-3, a rare isotope of helium gas, in springs is a good indicator of whether or not an area has a connection to the Earth’s mantle,” Newell says. “Warm, bubbling springs west of the 2002 earthquake rupture, along the Cantwell segment of the Denali Fault, have a strong helium-3 signature, indicating intact connections to the mantle. In contrast, springs along the ruptured fault segment only have atmospheric gases, suggesting a ‘roadblock’ preventing the flow of mantle helium to the surface.”
These observations, he says, have implications for how groundwater pathways along the fault are changed by earthquakes, and the timescales on which they heal.
“The last major earthquake on the Cantwell segment was 400 years ago, and the helium data suggest those mantel connections have been reestablished,” Newell says. “These bubbling springs are indicative of the possibility of a future large destructive earthquake along the Denali Fault segment near Denali National Park, which receives some 600,000 visitors each summer.”
The geoscientists also seek data on how fast helium can move from the mantle to the crust along active faults.
“That’s the ‘speed limit’ part of our research,” Newell says. “This is important as it reveals mantle-to-surface volatile flux and how fluid pressure gradients may impact fault strength and seismicity along the fault.”
The fault’s mantle fluid flow rates fall in the range observed for the world’s other major and active strike-slip faults that form plate boundaries, he says, including California’s San Andreas Fault and Turkey’s North Anatolian Fault Zone. These types of faults host large, devastating earthquakes, such as February 2023’s deadly earthquake on the East Anatolia Fault, which caused widespread destruction in Turkey and Syria.
“Quantifying crust-to-mantle connections along major strike-slip faults is critical for understanding linkages between deep fluid flow, seismicity and fault healing,” Newell says.
IMAGE: GLOBAL COBALT MINING AND PROCESSING FACILITIESview more
CREDIT: HOLLEY, E.A., ET AL., 2023, COBALT MINERALOGY AT THE IRON CREEK DEPOSIT, IDAHO COBALT BELT, USA: IMPLICATIONS FOR DOMESTIC CRITICAL MINERAL PRODUCTION. GEOLOGY
Contributed by Laura Fattaruso, GSA Science Communication Fellow
Boulder, Colo., USA: A new study published in Geologyevaluates the potential for cobalt extraction from the Idaho Cobalt Belt (ICB) of east-central Idaho, using a detailed study of the Iron Creek deposit. The ICB hosts the second largest known domestic resource of the critical mineral cobalt, one of the key ingredients in many rechargeable batteries needed for the green energy transition. Demand for cobalt is projected to increase more than 500% by 2050. Roughly 70% of the cobalt mined globally is from the Democratic Republic of the Congo, where mining practices have been criticized for human rights violations including hazardous working conditions, child labor, and human trafficking. The Biden administration has prioritized increasing the domestic production of critical minerals in the United States, invoking the Defense Production Act in 2022 to increase mineral development, and generating renewed interest in the ICB.
Understanding the mineralogy of the Iron Creek deposit is core to evaluating the amount of cobalt and other critical minerals that could be extracted from the site, and what methods are best for processing the ore. Cobalt was mined intermittently in the ICB during the 1900s, and the Blackbird Mine was designated as a Superfund site by the U.S. Environmental Protection Agency after closing. In 2022, the Australian mining company Jervois commenced mining at another site in the ICB. The Canadian company Electra Battery Materials has been exploring the Iron Creek deposit.
The rocks at Iron Creek are metasedimentary rocks of the Apple Creek Formation in the southwest Belt-Purcell Basin. The rocks of the Belt-Purcell Basin, which stretches between the U.S. and Canada, are more than one billion years old and have historically been mined for lead, zinc, silver, copper, cobalt, and gold.
The Iron Creek site could produce at least 6,000 metric tons of cobalt, but possibly much more. According to the new study, the cobalt at Iron Creek is mainly found in cobaltiferous pyrite. Other deposits in the ICB host cobalt in two other minerals—cobaltiferous arsenopyrite and cobaltite. In Iron Creek pyrite, the cobalt is bound up in the crystal lattice where it is substituted for iron, which has the same elemental charge as cobalt. Elizabeth Holley, Associate Professor of Mining Engineering at the Colorado School of Mines, and lead author of the study explains, “The cobalt is sitting in the pyrite itself, which means that in order to get it out, you essentially have to wreck the pyrite structure.”
The researchers also found inclusions within the pyrite of other critical minerals like tellurium, silver, and bismuth, but likely not enough to be economically viable for extraction under today’s economic and technical constraints. Chalcopyrite in the rocks is also a potential source for copper. Despite renewed interest in domestic mining, the U.S. currently lacks the facilities needed to process the ore from the ICB into usable cobalt. Holley explains, “If indeed the U.S. is interested in domestic supply chains for mining and processing of critical minerals, we don't have the infrastructure in the United States to process the cobalt that would come from the Idaho Cobalt Belt.”
The study authors conclude that the ore from Idaho should be divided and processed for copper and cobalt separately. Chalcopyrite can be processed for copper in existing copper smelting facilities within the US, and minerals with cobalt would ideally be processed in an autoclave—either an existing facility in Canada, or a new one to be built in the U.S.
The study also documents existing global cobalt mining and processing facilities and the connections between them—highlighting that the vast majority of the global cobalt supply is mined in the Democratic Republic of the Congo and then processed in China.
Despite a high projected need for cobalt, battery technologies that use other ingredients have been gaining attention and popularity, such as lithium-iron-phosphate batteries, also called LFPs. “Technology is evolving, and one of the new trendy research areas focuses on reducing the amount of cobalt in batteries. Will we still need the projected amounts of cobalt in the future? We don't know.” says Holley.
ICB hosts the second largest known domestic resource of cobalt
CREDIT
Iron Creek deposit location, Idaho cobalt belt (Electra Battery Materials, 2022)
FEATURED ARTICLE Cobalt mineralogy at the Iron Creek deposit, Idaho cobalt belt, USA: Implications for domestic critical mineral production E.A. Holley, N. Zaronikola, J. Trouba, K. Pfaff, J. Thompson, E. Spiller, C. Anderson, and R. Eggert Contact: Elizabeth Holley, Colorado School of Mines, eholley@mines.edu
IMAGE: LEFTOVER SLUDGE FROM THE 2008 COAL ASH SPILL AT THE KINGSTON TVA POWER PLANT. NEW RESEARCH INDICATES THAT THE NANOSCALE STRUCTURE OF THE COAL ASH PLAYS A LARGE PART IN WHETHER OR NOT TOXIC CHEMICALS CAN LEACH INTO THE ENVIRONMENT FROM SUCH EVENTS.view more
CREDIT: HELEN HSU-KIM, DUKE UNIVERSITY
DURHAM, N.C. – Everyone knows that burning coal causes air pollution that is harmful to the climate and human health. But the ash left over can often be harmful as well.
For example, Duke Energy long stored a liquified form of coal ash in 36 large ponds across the Carolinas. That all changed in 2014, when a spill at its Dan River site released 27 million gallons of ash pond water into the local environment. The incident raised concerns about the dangers associated with even trace amounts of toxic elements like arsenic and selenium in the ash. Little was known, however, about just how much of these hazardous materials were present in the ash water or how easily they could contaminate the surrounding environment.
Fears of future spills and seepage caused Duke Energy to agree to pay $1.1 billion to decommission most of its coal ash ponds over the coming years. Meanwhile, researchers are working on better ways of putting the ash to use, such as recycling it to recover valuable rare earth elements or incorporating it into building materials such as concrete. But to put any potential solution into action, researchers still must know which sources of coal ash pose a hazardous risk due to its chemical makeup — a question that scientists still struggle to answer.
In a new paper published June 6 in the journal Environmental Science: Nano, researchers at Duke University have discovered that these answers may remain elusive because nobody is thinking small enough. Using one of the newest, most advanced synchrotron light sources in the world — the National Synchrotron Light Source II at Brookhaven National Laboratory — the authors show that, at least for selenium and arsenic, the amount of toxic elements able to escape from coal ash depends largely on their nanoscale structures.
“These results show just how complex coal ash is as a material,” said Helen Hsu-Kim, professor of civil and environmental engineering at Duke University. “For example, we saw arsenic and selenium either attached to the surface of fine grain particles or encapsulated within them, which explains why these elements leach out of some coal ash sources more readily than others.”
It’s long been known that factors in the surrounding environment such as pH affect how well toxic elements can move from source to surroundings. In previous research, Hsu-Kim showed that the amount of oxygen in a toxin’s surroundings can greatly affect its chemistry, and that different sources of coal ash produce vastly different levels of byproducts.
But just because one source of coal ash is high in arsenic doesn’t necessarily mean that high amounts of arsenic will leach out of it. Similarly, various sources of ash respond differently to the same environmental conditions. The problem is complex, to say the least. To take a different approach, Hsu-Kim decided to take an even closer look at the source itself.
“Researchers in the field typically use x-ray microscopy with a resolution of one or two micrometers, which is about the same size as the fly ash particles themselves,” Hsu-Kim said. “So if a single particle is a single pixel, you’re not seeing how the elements are distributed across it.”
To shrink these pictures’ pixels to the nanoscale, Hsu-Kim turned to Catherine Peters, professor of civil and environmental engineering at Princeton University, and her colleagues to acquire time on the National Synchrotron Light Source II. The futuristic machine creates light beams 10 billion times brighter than the sun to reveal the chemical and atomic structure of materials using light beams ranging from infrared to hard X-rays.
Brookhaven’s capabilities were able to provide the researchers a nanoscale map of each particle along with the distribution of elements in each particle. The incredible resolution revealed that coal ash is a compilation of particles of all kinds and sizes.
For example, in one sample the researchers saw individual nanoparticles of selenium that were attached to bigger particles of coal ash, which is a chemical form of selenium that probably isn’t very soluble in water. But most of the ash had arsenic and selenium either locked inside individual grains or attached at the surface with relatively weak ionic bonds that are easily broken.
“It was almost like we saw something different in every sample we looked at,” Hsu-Kim said. “The wide array of differences really highlights why the main characteristic that we care about — how much of these elements leach out of the ash — varies so much between different samples.”
While nobody can say for sure what causes the coal ash to develop its unique composition, Hsu-Kim guesses that it is likely mostly related to how the coal was originally formed millions of years ago. But it might also have something to do with the power plants that burn the coal. Some plants inject activated carbon or lime into the flue gas, which captures mercury and sulfur emissions, respectively. At 1000 degrees Fahrenheit, toxins such as arsenic and selenium in the flue are gaseous, and the physics that dictate how the particles will cool and recombine to form ash is uncontrollable.
But regardless of the how, researchers now know that they should be paying closer attention to the fine details encapsulated within the end results.
This work was supported by the U.S. Department of Energy (DE-FE0031748) and the National Institute of Environmental Health Sciences (5U2C-ES030851). This research utilized U.S. DOE Office of Science User Facility resources at the Stanford Synchrotron Radiation Lightsource facility operated by SLAC National Accelerator Laboratory (DE-AC02-76SF0051) and at the Hard X-ray Nanoprobe (HXN) Beamline at 3-ID of the National Synchrotron Light Source II facility operated by Brookhaven National Laboratory (DE-SC0012704).
CITATION: “Nanoscale Heterogeneity of Arsenic and Selenium Species in Coal Fly Ash Particles: Analysis using enhanced spectroscopic imaging and speciation techniques,” Nelson A. Rivera, Jr, Florence T. Ling, Ajith Pattammattel, Hanfei Yan, Yong S. Chu, Catherine Peters, Heileen Hsu-Kim. Environmental Science: Nano, June 6, 2023. DOI: 10.1039/D2EN01056A
Arsenic Coal Ash
A nanoscale view of two different sources of coal ash shows major differences in how arsenic is part of its makeup. On the left, arsenic atoms (red) coat the surface of a coal ash particle made mainly of iron (green). On the right, the arsenic is encapsulated within the iron particle, making it more difficult for the arsenic to escape.
Selenium Coal Ash
A nanoscale view of two different sources of coal ash shows major differences in how selenium is part of its makeup. On the left, selenium (red) is diffusely distributed around multiple large ash grains made of iron (green) and carbon (blue). On the right, selenium is bound to the surface of ash grains made of iron and carbon, making it more difficult for the selenium to escape.
Nanoscale Heterogeneity of Arsenic and Selenium Species in Coal Fly Ash Particles: Analysis using enhanced spectroscopic imaging and speciation techniques
