Rocks in Canada's Quebec province found to be the oldest on Earth, World News
Along the eastern shore of Hudson Bay in Canada's northeastern province of Quebec, near the Inuit municipality of Inukjuak, resides a belt of volcanic rock that displays a blend of dark and light green colours, with flecks of pink and black. New testing shows that these are Earth's oldest-known rocks.
Two different testing methods found that rocks from an area called the Nuvvuagittuq Greenstone Belt in northern Quebec date to 4.16 billion years ago, a time known as the Hadean eon. The eon is named after the ancient Greek god of the underworld, Hades, owing to the hellish landscape thought to have existed then on Earth.
The research indicates that the Nuvvuagittuq Greenstone Belt harbors surviving fragments of Earth's oldest crust, the planet's outermost solid shell. The Nuvvuagittuq rocks are mainly metamorphosed volcanic rocks of basaltic composition. Metamorphosed rock is a kind that has been changed by heat and pressure over time. Basalt is a common type of volcanic rock.
The rocks tested in the new study were called intrusions. That means they formed when magma - molten rock - penetrated existing rock layers and then cooled and solidified underground.
The researchers applied two dating methods based on an analysis of the radioactive decay of the elements samarium and neodymium contained in them. Both produced the same conclusion - that the rocks were 4.16 billion years old.
Future chemical analyses of these rocks could provide insight into Earth's conditions during the Hadean, a time shrouded in mystery because of the paucity of physical remains.
"These rocks and the Nuvvuagittuq belt being the only rock record from the Hadean, they offer a unique window into our planet's earliest time to better understand how the first crust formed on Earth and what were the geodynamic processes involved," said University of Ottawa geology professor Jonathan O'Neil, who led the study published on Thursday (June 26) in the journal Science.
The rocks may have formed when rain fell on molten rock, cooling and solidifying it. That rain would have been composed of water evaporated from Earth's primordial seas.
"Since some of these rocks were also formed from precipitation from the ancient seawater, they can shed light on the first oceans' composition, temperatures and help establish the environment where life could have begun on Earth," O'Neil said.
Until now, the oldest-known rocks were ones dating to about 4.03 billion years ago from Canada's Northwest Territories, O'Neil said.
While the Nuvvuagittuq samples are now the oldest-known rocks, tiny crystals of the mineral zircon from western Australia have been dated to 4.4 billion years old.
The Hadean ran from Earth's formation roughly 4.5 billion years ago until 4.03 billion years ago. Early during this eon, a huge collision occurred that is believed to have resulted in the formation of the moon. But by the time the Nuvvuagittuq rocks formed, Earth had begun to become a more recognisable place.
"The Earth was certainly not a big ball of molten lava during the entire Hadean eon, as its name would suggest. By nearly 4.4 billion years ago, a rocky crust already existed on Earth, likely mostly basaltic and covered with shallow and warmer oceans. An atmosphere was present, but different than the present-day atmosphere," O'Neil said.
There had been some controversy over the age of Nuvvuagittuq rocks.
As reported in a study published in 2008, previous tests on samples from the volcanic rock layers that contained the intrusions yielded conflicting dates - one giving an age of 4.3 billion years and another giving a younger age of 3.3 to 3.8 billion years. O'Neil said the discrepancy may have been because the method that produced the conclusion of a younger age was sensitive to thermal events that have occurred since the rock formed, skewing the finding.
The new study, with two testing methods producing harmonious conclusions on the age of the intrusion rocks, provides a minimum age for the volcanic rocks that contain these intrusions, O'Neil added.
"The intrusion would be 4.16 billion years old, and because the volcanic rocks must be older, their best age would be 4.3 billion years old, as supported by the 2008 study," O'Neil said.
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AsiaOne
19 hours ago
- AsiaOne
Rocks in Canada's Quebec province found to be the oldest on Earth, World News
Along the eastern shore of Hudson Bay in Canada's northeastern province of Quebec, near the Inuit municipality of Inukjuak, resides a belt of volcanic rock that displays a blend of dark and light green colours, with flecks of pink and black. New testing shows that these are Earth's oldest-known rocks. Two different testing methods found that rocks from an area called the Nuvvuagittuq Greenstone Belt in northern Quebec date to 4.16 billion years ago, a time known as the Hadean eon. The eon is named after the ancient Greek god of the underworld, Hades, owing to the hellish landscape thought to have existed then on Earth. The research indicates that the Nuvvuagittuq Greenstone Belt harbors surviving fragments of Earth's oldest crust, the planet's outermost solid shell. The Nuvvuagittuq rocks are mainly metamorphosed volcanic rocks of basaltic composition. Metamorphosed rock is a kind that has been changed by heat and pressure over time. Basalt is a common type of volcanic rock. The rocks tested in the new study were called intrusions. That means they formed when magma - molten rock - penetrated existing rock layers and then cooled and solidified underground. The researchers applied two dating methods based on an analysis of the radioactive decay of the elements samarium and neodymium contained in them. Both produced the same conclusion - that the rocks were 4.16 billion years old. Future chemical analyses of these rocks could provide insight into Earth's conditions during the Hadean, a time shrouded in mystery because of the paucity of physical remains. "These rocks and the Nuvvuagittuq belt being the only rock record from the Hadean, they offer a unique window into our planet's earliest time to better understand how the first crust formed on Earth and what were the geodynamic processes involved," said University of Ottawa geology professor Jonathan O'Neil, who led the study published on Thursday (June 26) in the journal Science. The rocks may have formed when rain fell on molten rock, cooling and solidifying it. That rain would have been composed of water evaporated from Earth's primordial seas. "Since some of these rocks were also formed from precipitation from the ancient seawater, they can shed light on the first oceans' composition, temperatures and help establish the environment where life could have begun on Earth," O'Neil said. Until now, the oldest-known rocks were ones dating to about 4.03 billion years ago from Canada's Northwest Territories, O'Neil said. While the Nuvvuagittuq samples are now the oldest-known rocks, tiny crystals of the mineral zircon from western Australia have been dated to 4.4 billion years old. The Hadean ran from Earth's formation roughly 4.5 billion years ago until 4.03 billion years ago. Early during this eon, a huge collision occurred that is believed to have resulted in the formation of the moon. But by the time the Nuvvuagittuq rocks formed, Earth had begun to become a more recognisable place. "The Earth was certainly not a big ball of molten lava during the entire Hadean eon, as its name would suggest. By nearly 4.4 billion years ago, a rocky crust already existed on Earth, likely mostly basaltic and covered with shallow and warmer oceans. An atmosphere was present, but different than the present-day atmosphere," O'Neil said. There had been some controversy over the age of Nuvvuagittuq rocks. As reported in a study published in 2008, previous tests on samples from the volcanic rock layers that contained the intrusions yielded conflicting dates - one giving an age of 4.3 billion years and another giving a younger age of 3.3 to 3.8 billion years. O'Neil said the discrepancy may have been because the method that produced the conclusion of a younger age was sensitive to thermal events that have occurred since the rock formed, skewing the finding. The new study, with two testing methods producing harmonious conclusions on the age of the intrusion rocks, provides a minimum age for the volcanic rocks that contain these intrusions, O'Neil added. "The intrusion would be 4.16 billion years old, and because the volcanic rocks must be older, their best age would be 4.3 billion years old, as supported by the 2008 study," O'Neil said. [[nid:706868]]
Straits Times
a day ago
- Straits Times
Rocks in Canada's Quebec province found to be the oldest on Earth
A close-up view of metagabbroic rocks from the Nuvvuagittuq greenstone belt in Nunavik, Quebec, Canada, that are 4.16 billion years old is seen in this photograph released on June 26, O'Neil/Handout via REUTERS A view from the Nuvvuagittuq greenstone belt, Nunavik, Quebec, Canada, in this photograph released on June 26, 2025. Jonathan O'Neil/Handout via REUTERS An outcrop of meta gabbroic rocks from the Nuvvuagittuq greenstone belt in Nunavik, Quebec, Canada, that are 4.16 billion years old, in this photograph released on June 26, 2025. A knife is pictured for scale. Jonathan O'Neil/Handout via REUTERS Along the eastern shore of Hudson Bay in Canada's northeastern province of Quebec, near the Inuit municipality of Inukjuak, resides a belt of volcanic rock that displays a blend of dark and light green colors, with flecks of pink and black. New testing shows that these are Earth's oldest-known rocks. Two different testing methods found that rocks from an area called the Nuvvuagittuq Greenstone Belt in northern Quebec date to 4.16 billion years ago, a time known as the Hadean eon. The eon is named after the ancient Greek god of the underworld, Hades, owing to the hellish landscape thought to have existed then on Earth. The research indicates that the Nuvvuagittuq Greenstone Belt harbors surviving fragments of Earth's oldest crust, the planet's outermost solid shell. The Nuvvuagittuq rocks are mainly metamorphosed volcanic rocks of basaltic composition. Metamorphosed rock is a kind that has been changed by heat and pressure over time. Basalt is a common type of volcanic rock. The rocks tested in the new study were called intrusions. That means they formed when magma - molten rock - penetrated existing rock layers and then cooled and solidified underground. The researchers applied two dating methods based on an analysis of the radioactive decay of the elements samarium and neodymium contained in them. Both produced the same conclusion - that the rocks were 4.16 billion years old. Future chemical analyses of these rocks could provide insight into Earth's conditions during the Hadean, a time shrouded in mystery because of the paucity of physical remains. "These rocks and the Nuvvuagittuq belt being the only rock record from the Hadean, they offer a unique window into our planet's earliest time to better understand how the first crust formed on Earth and what were the geodynamic processes involved," said University of Ottawa geology professor Jonathan O'Neil, who led the study published on Thursday in the journal Science. The rocks may have formed when rain fell on molten rock, cooling and solidifying it. That rain would have been composed of water evaporated from Earth's primordial seas. "Since some of these rocks were also formed from precipitation from the ancient seawater, they can shed light on the first oceans' composition, temperatures and help establish the environment where life could have begun on Earth," O'Neil said. Until now, the oldest-known rocks were ones dating to about 4.03 billion years ago from Canada's Northwest Territories, O'Neil said. While the Nuvvuagittuq samples are now the oldest-known rocks, tiny crystals of the mineral zircon from western Australia have been dated to 4.4 billion years old. The Hadean ran from Earth's formation roughly 4.5 billion years ago until 4.03 billion years ago. Early during this eon, a huge collision occurred that is believed to have resulted in the formation of the moon. But by the time the Nuvvuagittuq rocks formed, Earth had begun to become a more recognizable place. "The Earth was certainly not a big ball of molten lava during the entire Hadean eon, as its name would suggest. By nearly 4.4 billion years ago, a rocky crust already existed on Earth, likely mostly basaltic and covered with shallow and warmer oceans. An atmosphere was present, but different than the present-day atmosphere," O'Neil said. There had been some controversy over the age of Nuvvuagittuq rocks. As reported in a study published in 2008, previous tests on samples from the volcanic rock layers that contained the intrusions yielded conflicting dates - one giving an age of 4.3 billion years and another giving a younger age of 3.3 to 3.8 billion years. O'Neil said the discrepancy may have been because the method that produced the conclusion of a younger age was sensitive to thermal events that have occurred since the rock formed, skewing the finding. The new study, with two testing methods producing harmonious conclusions on the age of the intrusion rocks, provides a minimum age for the volcanic rocks that contain these intrusions, O'Neil added. "The intrusion would be 4.16 billion years old, and because the volcanic rocks must be older, their best age would be 4.3 billion years old, as supported by the 2008 study," O'Neil said. REUTERS Join ST's Telegram channel and get the latest breaking news delivered to you.
Straits Times
14-06-2025
- Straits Times
Study shows mercury levels in arctic wildlife could rise for centuries
Previous research has shown that mercury can persist in oceans for more than 300 years. PHOTO: AFP Levels of mercury in Arctic wildlife could continue to rise significantly even as countries curb their emissions, a new study suggests. Researchers analysed more than 700 samples of fish, mammals and peat collected across Greenland over the past 40 years and found evidence that the mercury in them was distributed by ocean currents. The finding, published this week in the journal Nature Communications, helps explain why levels of mercury contamination have continued increasing in the Arctic even as global emissions have begun to plateau. 'We got a lot of surprises when we analysed the data,' said Dr Jens Sondergaard, a senior ecological science researcher at Aarhus University in Denmark and lead author of the study. 'It's a really striking trend.' Exposure to high concentrations of mercury, a potent neurotoxin, can lead to neurological and other health-related effects and the study confirms that mercury emitted today could continue posing a large threat to humans and wildlife in the region for centuries. By analysing mercury isotopes, a unique kind of chemical signature that can be matched like a fingerprint, the researchers traced the spread of mercury contamination to the patterns of ocean currents around Greenland. Previous research has shown that mercury can persist in oceans for more than 300 years. The results indicate that large, century-old stores of mercury in the ocean could actually be the dominant means by which the element proliferates through marine ecosystems in the Arctic, Dr Sondergaard said. This poses a problem for people who live in the region, particularly Inuit communities that hunt large marine mammals with high concentrations of mercury, like seals. 'It's a quite unique situation. This population that ought to be, you know, in a clean environment, has some of the highest concentrations,' said Professor Rune Dietz, a professor at Aarhus University and a co-author of the study. Mercury is primarily spread through the environment by human activities such as burning coal or mining heavy minerals, like gold. According to a 2023 estimate by researchers at the Harvard School of Engineering and Applied Sciences, atmospheric mercury concentrations have risen nearly sevenfold since the 1500s. Mercury emissions in North America and Europe began falling in the 1970s, following the enactment of a series of environmental regulations like the Clean Air Act. Other countries with high levels of pollution, like China and India, began curbing their emissions a little more than a decade ago, after signing a global agreement known as the Minamata Convention. Earlier this week, the Environmental Protection Agency began moving to loosen limits on mercury emissions, along with those on other pollutants, from power plants. There is no known safe level of methylmercury, the toxic form of mercury that can form in aquatic environments. In high bodily concentrations it can cause neurological problems, kidney damage and affect fetuses in the womb. Despite hosting almost no mercury-producing industries, the Arctic has become a hot spot of contamination, in part because of the natural pattern of the Earth's atmosphere and oceans, which tend to circulate pollutants toward higher latitudes. Large predators that eat significant amounts of contaminated prey end up ingesting the most mercury. Studies have shown that such marine mammals, like ring seals and pilot whales, can carry concentrations of mercury up to 50 times greater than some smaller fish, like herring. The new paper found that concentrations of mercury found in polar bear tissues have doubled in the last 40 years. Professor Niladri Basu, a professor of environmental health sciences at McGill University in Canada who was not affiliated with the study, said that Indigenous groups with hunting practices are most at risk for exposure to mercury. 'The species that drive exposure in communities are not species that are harvested for global transport and trade,' he said. Prof Basu added that mercury advisories have led to some Inuit communities cutting back on traditional food sources, representing a significant cultural loss. Emissions aren't the only mercury contamination threat in the Arctic. In 2024, a study found that the region's frozen soils, known as permafrost, have been accumulating mercury for centuries, reaching levels estimated to be higher than the atmosphere, oceans and life-forms combined. As climate change continues to warm the planet, scientists worry that these stores of mercury could be released. In November, international delegates will meet for the Minamata Convention's sixth major meeting. 2025 also presents the first deadline for the more than 120 countries who signed on to the treaty, to begin phasing out mercury use in certain types of production. Even in light of the global action on mercury, Prof Basu said, it could take centuries for the Arctic to recover. 'On one hand, we want to take action, and we have to recognise that mistakes are made and that we can't continue as business as usual,' he said. 'But on the other hand, we have to recognise that it's going to take a long, long time to undo all the damage.' NYTIMES Join ST's Telegram channel and get the latest breaking news delivered to you.
