Rocks in Canada Are Confirmed as World's Oldest
In 2008 scientists reported that rocks in Canada were the world's oldest. New data appear to confirm this contested claim
By & Nature magazine
On the shores of Hudson Bay in northeastern Canada lie what could be the world's oldest rocks. A study now suggests they are at least 4.16 billion years old — 160 million years older than any others recorded, and the only piece of Earth's crust known to have survived from the planet's earliest eon.
In 2008, researchers reported that these rocks dated back 4.3 billion years, a claim that other scientists contested. Work reported today in Science 1 seems to confirm that the rocks, known as the Nuvvuagittuq Greenstone Belt, are record-breakers.
Researchers say the rock formation offers a unique window into early Earth, after the planet cooled from its fiery birth 4.5 billion years ago.
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
'It's not a matter of 'my rock is older than yours',' says Jonathan O'Neil, a geologist at Ottawa University who leads the research team. 'It's just that this is a unique opportunity to understand what was going on during that time.'
The 'oldest rocks' label has sometimes backfired. In the past few years, other teams have chiselled many samples out of the Nuvvuagittuq belt, leaving the landscape scarred. Last year, the local Inuit community closed access to the rocks to prevent further despoliation.
Only a handful of geological samples in the world date back to 3.8 billion years or older. Of those, the oldest undisputed rocks are found in the Acasta gneiss formation in Canada's Northwest Territories; at 4 billion years old, they mark the boundary between Earth's first geological eon, the Hadean, and the following one, the Archaean. Geologists have also found tiny mineral crystals dating back to the Hadean — such as 4.4-billion-year-old zircon crystals from Western Australia — that have become embedded into newer rock. But there are no known surviving chunks of crust from the Hadean — except, perhaps, the Nuvvuagittuq Greenstone Belt. It consists primarily of material that started out as volcanic basalt before undergoing various modifications during Earth's tortured history.
In their 2008 work, O'Neil and his colleagues analysed the chemical imprint left by the radioactive decay of the isotope samarium-146 into neodymium-142 to calculate that the Nuvvuagittuq rocks were 4.3 billion years old. (Samarium-146 is a short-lived isotope that was depleted in Earth's first 500 million years, and none was left after about 4 billion years ago.) Other scientists challenged that work, arguing, for instance, that Hadean-age crust had become mixed into younger crust, contaminating the results.
For the latest work, O'Neil's team analysed some once-molten rocks that had intruded into the main Nuvvuagittuq rocks like a knife cutting into a cake. By dating the intruded rocks, O'Neil and his colleagues were able to establish a minimum age for the cake itself. They used two radioactive clocks: the decay of samarium-146 into neodymium-142 and that of samarium-147 into neodymium-143. Both yielded ages of around 4.16 billion years for the intruded rocks. 'If you don't agree with this, then you need a very speculative, intricate model to get to the same answer,' says O'Neil.
Having both clocks agree on an age — which wasn't the case in the earlier work — strengthens the case for a Hadean age for the rocks, says Bernard Bourdon, a geochemist at the University of Lyon in France. He remains circumspect, though, and says he would like to see additional lines of evidence, involving other radioactive isotope decays. 'I would be happy if these rocks were truly Hadean, but I think we still need to be cautious,' Bourdon says.
The paper 'provides a new data set that hopefully can advance this discussion', says Richard Carlson, a geochemist at Carnegie Science in Washington DC who has collaborated with O'Neil in previous work. To Carlson, the bulk of the evidence suggests that the rocks are indeed Hadean.
For now, more answers might have to wait. The Pituvik Landholding Corporation in Inukjuak, Canada — the Inuit group that is steward of the land in question — is not currently granting permits for further scientific study, due to the earlier damage by other groups. 'It's unfortunate, but I would do the same,' O'Neil says.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
2 days ago
- Yahoo
When is the next full 'buck moon'? What to know about celestial events in July
There are 12 full moons in 2025, and July will bring one that's called the 'Buck Moon.' A full moon occurs — simply put — when the Earth falls between the sun and the moon, which results in the visible portion of the moon being lit by the sun. If you're a regular sky gazer, keeping track of celestial movements, or just curious this month, here is what you need to know about upcoming lunar activity and other planetary sightings in July. The next Buck Moon will arrive on Thursday, July 10, and is expected to be at peak illumination at 4:37 p.m. Eastern time, according to The Old Farmer's Almanac. Derived from Indigenous American, European and colonial American influences, moon names signify a connection to the natural world. In July, as part of a yearly renewal process, male deer grow new antlers at peak capacity after having shed the old horns at the end of the rutting season — hence lending the name Buck Moon. Some other names for the July full moon are Thunder Moon, due to the thunderstorms, and Halfway Summer Moon. This moon is also called Berry Moon, Salmon Moon and Feather Moulting Moon. Middletown residents and others in the mid-Hudson Valley can spot the rise of the moon above the horizon at 8:58 p.m. by looking in the southeast direction. The moon will set at 4:50 a.m., southwestward. If you want to see surface details, you will need binoculars or a telescope. You can also use a digital camera. More: NYSEG seeks state approval for steep rate hikes for gas, electric customers Long-range forecast by Climate Prediction Center shows normal or leaning-above-normal temperatures and precipitation levels for July 9-15. If you are interested in locating other planets and constellations in the sky in July, here's what NASA recommends: Jupiter is expected in the second half of the month in the east during the hour before dawn — positioned low in the sky, rising higher each day. Mars is expected to appear all month in the west for a couple of hours, starting at the end of the twilight period — positioned approximately 20 degrees over the horizon line. Mercury makes a brief appearance in the first week of July in the western skies after dusk for up to 45 minutes — positioned 10 degrees above the horizon line or lower. Saturn will be visible all month at midnight — positioned rising high in the southern sky by sunrise. Venus will rise all month in early morning in the east in the hours before dawn. Aquila Constellation, the eagle-shaped cluster of stars, will appear all of July in the east in the first half of the night, anchored by its brightest star, Altair. This article originally appeared on Times Herald-Record: When to see the Buck Moon and other July events in mid-Hudson Valley
Scientific American
2 days ago
- Scientific American
4,800-Year-Old Teeth Yield First Human Genome from Ancient Egypt
Teeth from an elderly man who lived around the time that the earliest pyramids were built have yielded the first full human genome sequence from ancient Egypt. The remains are 4,800 to 4,500 years old, overlapping with a period in Egyptian history known as the Old Kingdom or the Age of Pyramids. They harbour signs of ancestry similar to that of other ancient North Africans, as well as of people from the Middle East, researchers report today in Nature. 'It's incredibly exciting and important,' says David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts, who was not involved in the study. 'We always hoped we would get our first ancient DNA from mummies.' On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Numerous labs have tried to extract DNA from ancient Egyptian remains. In 1985, evolutionary geneticist Svante Pääbo reported the first ancient DNA sequences from any human: several thousand DNA letters from a 2,400-year-old Egyptian mummy of a child. But Pääbo, who won a Nobel prize in 2022 for other work, later realized that the sequences were contaminated with modern DNA — possibly his own. A 2017 study generated limited genome data from three Egyptian mummies that lived between 3,600 and 2,000 years ago. The hot North African climate speeds up the breakdown of DNA, and the mummification process might also accelerate it, said Pontus Skoglund, a palaeogeneticist at the Francis Crick Institute in London who co-led the Nature study, at a press briefing. 'Mummified individuals are probably not a great way to preserve DNA.' The remains that Skoglund's team sequenced pre-date widespread mummification: the person was interred instead in a ceramic pot, a sign of high, but not elite, status. The remains were found at an archaeological site called Nuwayrat, 265 kilometres south of Cairo along the Nile river. The teeth and bones were discovered in 1902, when Egypt was under British colonial rule. They were donated to institutions in Liverpool, UK, where they have been ever since, even surviving German bombing during the Second World War. Low expectations Skoglund says his expectations were low when his team extracted DNA from several teeth from the Nuwayrat individual. But two samples contained enough authentic ancient DNA to generate a full genome sequence. Y-chromosome sequences indicated that the remains belonged to a male. The majority of his DNA resembled that of early farmers from the Neolithic period of North Africa around 6,000 years ago. The rest most closely matched people in Mesopotamia, a historical Middle Eastern region that was home to the ancient Sumerian civilization, and was where some of the first writing systems emerged. It's not clear whether this implies a genetic direct link between members of Mesopotamian cultures and people in ancient Egypt — also hinted at by similarities in some cultural artefacts — or whether the man's Mesopotamian ancestry arrived through other unsampled populations, the researchers say. The rest of the ancient Egyptian man's bones revealed more details about his life. Evidence of arthritis and osteoporosis suggest he died at an advanced age for the time, possibly in his sixties. Other signs of wear indicate a life of physical toil, sitting hunched over on hard surfaces. On the basis of this and imagery from other tombs from this period, he might have been a potter, said co-author Joel Irish, a bioarchaeologist at Liverpool John Moores University, at the press briefing. 'The publication of a whole-genome data set of an ancient Egyptian constitutes a significant achievement in the field of molecular Egyptology,' says Yehia Gad, a geneticist at Egypt's National Research Centre in Cairo, who praises the researchers for presenting the provenance of the remains clearly. But he points out that the genome is from one individual and might not fully represent ancient Egypt's gene pool, which was probably a melting pot of different ancestries. For this reason, researchers are eager for more ancient Egyptian genome data — perhaps even from a mummy. Advances in ancient-genomics technology and local capacity — Gad supervises an ancient DNA lab at the National Museum of Egyptian Civilization in Cairo — means it hopefully won't take another 40 years.
Yahoo
2 days ago
- Yahoo
Air pollution and herbal medicines could be behind lung cancer in non-smokers, study finds
Air pollution and traditional herbal medicines could be major risk factors contributing to the development of lung cancer in people with no history of smoking, a groundbreaking new study has found. While smoking is a major risk factor for lung cancer, rates of the malignancy appear to be increasing among those who have never smoked, even with tobacco use declining globally. Previous studies have shown that lung cancer disproportionately affects non-smoking women, particularly those with Asian ancestry, and is more prevalent in East Asia than in Western nations. Now, a new study, published on Wednesday in the journal Nature, provides compelling evidence that air pollution and herbal medicines could be behind genetic mutations linked to the development of lung cancer in non-smokers. 'We are seeing this problematic trend that never-smokers are increasingly getting lung cancer, but we haven't understood why,' said Ludmil Alexandrov, an author of the study from the University of California San Diego. 'Our research shows that air pollution is strongly associated with the same types of DNA mutations we typically associate with smoking.' Most lung cancer prevalence studies haven't separated data of smokers from that of non-smokers, providing limited insights into potential causes in those patients. The latest study collected data from never-smokers worldwide and used genomics to find environmental factors likely behind these cancers. 'This is an urgent and growing global problem that we are working to understand regarding never-smokers,' said Maria Teresa Landi, co-author of the study from the US National Cancer Institute. While previous studies have shown a potential link between air pollution and lung cancer in never-smokers, the new research goes further by revealing a genomic link. In this comprehensive study, scientists analysed lung tumours from 871 never-smokers living in 28 regions with different levels of air pollution across Africa, Asia, Europe and North America. Researchers used genome sequencing methods to identify distinct patterns of genetic mutations which act like molecular fingerprints of past exposures. They then compared the genomic data with pollution estimates based on satellite and ground-level measurements of fine particulate matter. This helped them estimate long-term exposure of the patients to air pollution. The study found that never-smokers living in more polluted environments had significantly more mutations in their lung tumours, particularly the kinds which directly promote cancer development. Scientists also found more molecular signatures in this group, which are linked to cancer and serve as a record of all past exposures to mutation-causing environmental factors. For instance, these individuals had a nearly 4-fold increase in a mutational signature molecule linked to tobacco smoking and a 76 per cent increase in another signature linked to ageing. 'What we see is that air pollution is associated with an increase in somatic mutations, including those that fall under known mutational signatures attributed to tobacco smoking and ageing,' said Marcos Díaz-Gay, co-author of the study. Scientists found that the more pollution someone was exposed to, the more mutations were found in their lung tumours, as well as greater signs of their cells undergoing accelerated ageing. Another environmental risk unravelled by the study was aristolochic acid, a known cancer-causing chemical found in some traditional Chinese and Ayurvedic herbal medicines. This chemical, extracted from plants of the birthwort family, was found linked to a signature mutation in lung tumours of never-smokers from Taiwan. Although ingestion of this plant chemical has been linked previously to bladder, gut, kidney, and liver cancers, the latest study is the first to report evidence that it may contribute to lung cancer. 'This raises new concerns about how traditional remedies might unintentionally raise cancer risk,' Dr Landi said. 'It also presents a public health opportunity for cancer prevention, particularly in Asia.' The study also found an intriguing new mutation signature which appears in the lung tumours of most never-smokers but is absent in smokers. 'We don't yet know what's driving it,' Dr Alexandrov said. 'This is something entirely different, and it opens up a whole new area of investigation.'
