Latest news with #JonathanO'Neil
Yahoo
08-07-2025
- Science
- Yahoo
Scientists unlock secrets of oldest rocks on Earth
Earth formed about 4.6 billion years ago, during the geological eon known as the Hadean. The name 'Hadean' comes from the Greek god of the underworld, reflecting the extreme heat that likely characterised the planet at the time. By 4.35 billion years ago, the Earth might have cooled down enough for the first crust to form and life to emerge. However, very little is known about this early chapter in Earth's history, as rocks and minerals from that time are extremely rare. This lack of preserved geological records makes it difficult to reconstruct what the Earth looked like during the Hadean Eon, leaving many questions about its earliest evolution unanswered. We are part of a research team that has confirmed the oldest known rocks on Earth are located in northern Québec. Dating back 4.3 billion years, these rocks provide a rare and invaluable glimpse into the origins of our planet. The Hadean Eon is the first period in the geological timescale, spanning from Earth's formation 4.6 billion years ago and ending around 4.03 billion years ago. The oldest terrestrial materials ever dated by scientists are extremely rare zircon minerals that were discovered in western Australia. These zircons were formed as early as 4.4 billion years ago, and while their host rock eroded away, the durability of zircons allowed them to be preserved for a long time. Studies of these zircon minerals has given us clues about the Hadean environment, and the formation and evolution of Earth's oldest crust. The zircons' chemistry suggests that they formed in magmas produced by the melting of sediments deposited at the bottom of an ancient ocean. This suggests that the zircons are evidence that the Hadean Eon cooled rapidly, and liquid water oceans were formed early on. Other research on the Hadean zircons suggests that the Earth's earliest crust was mafic (rich in magnesium and iron). Until recently, however, the existence of that crust remained to be confirmed. In 2008, a study led by associate professor Jonathan O'Neil (then a McGill University doctoral student) proposed that rocks of this ancient crust had been preserved in northern Québec and were the only known vestige of the Hadean. Since then, the age of those rocks — found in the Nuvvuagittuq Greenstone Belt — has been controversial and the subject of ongoing scientific debate. The Nuvvuagittuq Greenstone Belt is located in the northernmost region of Québec, in the Nunavik region above the 55th parallel. Most of the rocks there are metamorphosed volcanic rocks, rich in magnesium and iron. The most common rocks in the belt are called the Ujaraaluk rocks, meaning 'big old solid rock' in Inuktitut. The age of 4.3 billion years was proposed after variations in neodymium-142 were detected, an isotope produced exclusively during the Hadean through the radioactive decay of samarium-146. The relationship between samarium and neodymium isotope abundances had been previously used to date meteorites and lunar rocks, but before 2008 had never been applied to Earth rocks. This interpretation, however, was challenged by several research groups, some of whom studied zircons within the belt and proposed a younger age of at most 3.78 billion years, placing the rocks in the Archean Eon instead. In the summer of 2017, we returned to the Nuvvuagittuq belt to take a closer look at the ancient rocks. This time, we collected intrusive rocks — called metagabbros — that cut across the Ujaraaluk rock formation, hoping to obtain independent age constraints. The fact that these newly studied metagabbros are in intrusion in the Ujaraaluk rocks implies that the latter must be older. The project was led by masters student Chris Sole at the University of Ottawa, who joined us in the field. Back in the laboratory, we collaborated with French geochronologist Jean-Louis Paquette. Additionally, two undergraduate students — David Benn (University of Ottawa) and Joeli Plakholm (Carleton University) participated to the project. We combined our field observations with petrology, geochemistry, geochronology and applied two independent samarium-neodymium age dating methods, dating techniques used to assess the absolute ages of magmatic rocks, before these become metamorphic rocks. Both assessments yielded the same result: the intrusive rocks are 4.16 billion years old. Since these metagabbros cut across the Ujaraaluk formation, the Ujaraaluk rocks must be even older, placing them firmly in the Hadean Eon. Studying the Nuvvuagittuq rocks, the only preserved rocks from the Hadean, provides a unique opportunity to learn about the earliest history of our planet. They can help us understand how the first continents formed, and how and when Earth's environment evolved to become habitable. Hanika Rizo is an Associate Professor in the Department of Earth Sciences at Carleton University Jonathan O'Neil is a Professor in Earth and Environmental Sciences at L'Université d'Ottawa/University of Ottawa This article was originally published by The Conversation and is republished under a Creative Commons licence. Read the original article
Gulf Today
07-07-2025
- Science
- Gulf Today
Scientists unlock secrets of oldest rocks on Earth
Hanika Rizo and Jonathan O'Neil, The Independent Earth formed about 4.6 billion years ago, during the geological eon known as the Hadean. The name "Hadean" comes from the Greek god of the underworld, reflecting the extreme heat that likely characterised the planet at the time. By 4.35 billion years ago, the Earth might have cooled down enough for the first crust to form and life to emerge. However, very little is known about this early chapter in Earth's history, as rocks and minerals from that time are extremely rare. This lack of preserved geological records makes it difficult to reconstruct what the Earth looked like during the Hadean Eon, leaving many questions about its earliest evolution unanswered. We are part of a research team that has confirmed the oldest known rocks on Earth are located in northern Québec. Dating back 4.3 billion years, these rocks provide a rare and invaluable glimpse into the origins of our planet. Remains from the Hadean EonThe Hadean Eon is the first period in the geological timescale, spanning from Earth's formation 4.6 billion years ago and ending around 4.03 billion years ago. The oldest terrestrial materials ever dated by scientists are extremely rare zircon minerals that were discovered in western Australia. These zircons were formed as early as 4.4 billion years ago, and while their host rock eroded away, the durability of zircons allowed them to be preserved for a long time. Studies of these zircon minerals has given us clues about the Hadean environment, and the formation and evolution of Earth's oldest crust. The zircons' chemistry suggests that they formed in magmas produced by the melting of sediments deposited at the bottom of an ancient ocean. This suggests that the zircons are evidence that the Hadean Eon cooled rapidly, and liquid water oceans were formed early on. Other research on the Hadean zircons suggests that the Earth's earliest crust was mafic (rich in magnesium and iron). Until recently, however, the existence of that crust remained to be confirmed. In 2008, a study led by associate professor Jonathan O'Neil (then a McGill University doctoral student) proposed that rocks of this ancient crust had been preserved in northern Québec and were the only known vestige of the Hadean. Since then, the age of those rocks — found in the Nuvvuagittuq Greenstone Belt — has been controversial and the subject of ongoing scientific debate. 'Big, old solid rock'The Nuvvuagittuq Greenstone Belt is located in the northernmost region of Québec, in the Nunavik region above the 55th parallel. Most of the rocks there are metamorphosed volcanic rocks, rich in magnesium and iron. The most common rocks in the belt are called the Ujaraaluk rocks, meaning "big old solid rock" in Inuktitut. The age of 4.3 billion years was proposed after variations in neodymium-142 were detected, an isotope produced exclusively during the Hadean through the radioactive decay of samarium-146. The relationship between samarium and neodymium isotope abundances had been previously used to date meteorites and lunar rocks, but before 2008 had never been applied to Earth rocks. This interpretation, however, was challenged by several research groups, some of whom studied zircons within the belt and proposed a younger age of at most 3.78 billion years, placing the rocks in the Archean Eon instead. Confirming the Hadean AgeIn the summer of 2017, we returned to the Nuvvuagittuq belt to take a closer look at the ancient rocks. This time, we collected intrusive rocks — called metagabbros — that cut across the Ujaraaluk rock formation, hoping to obtain independent age constraints. The fact that these newly studied metagabbros are in intrusion in the Ujaraaluk rocks implies that the latter must be older. The project was led by masters student Chris Sole at the University of Ottawa, who joined us in the field. Back in the laboratory, we collaborated with French geochronologist Jean-Louis Paquette. Additionally, two undergraduate students — David Benn (University of Ottawa) and Joeli Plakholm (Carleton University) participated to the project. We combined our field observations with petrology, geochemistry, geochronology and applied two independent samarium-neodymium age dating methods, dating techniques used to assess the absolute ages of magmatic rocks, before these become metamorphic rocks. Both assessments yielded the same result: the intrusive rocks are 4.16 billion years old. The oldest rocksSince these metagabbros cut across the Ujaraaluk formation, the Ujaraaluk rocks must be even older, placing them firmly in the Hadean Eon. Studying the Nuvvuagittuq rocks, the only preserved rocks from the Hadean, provides a unique opportunity to learn about the earliest history of our planet. They can help us understand how the first continents formed, and how and when Earth's environment evolved to become habitable. Hanika Rizo is an Associate Professor in the Department of Earth Sciences at Carleton University
NDTV
07-07-2025
- Science
- NDTV
Oldest Rock On Earth Confirmed To Be Over 4 Billion Years Old
Ottawa: Earth formed about 4.6 billion years ago, during the geological eon known as the Hadean. The name "Hadean" comes from the Greek god of the underworld, reflecting the extreme heat that likely characterized the planet at the time. By 4.35 billion years ago, the Earth might have cooled down enough for the first crust to form and life to emerge. However, very little is known about this early chapter in Earth's history, as rocks and minerals from that time are extremely rare. This lack of preserved geological records makes it difficult to reconstruct what the Earth looked like during the Hadean Eon, leaving many questions about its earliest evolution unanswered. We are part of a research team that has confirmed the oldest known rocks on Earth are located in northern Québec. Dating back more than four billion years, these rocks provide a rare and invaluable glimpse into the origins of our planet. Remains from the Hadean Eon The Hadean Eon is the first period in the geological timescale, spanning from Earth's formation 4.6 billion years ago and ending around 4.03 billion years ago. The oldest terrestrial materials ever dated by scientists are extremely rare zircon minerals that were discovered in western Australia. These zircons were formed as early as 4.4 billion years ago, and while their host rock eroded away, the durability of zircons allowed them to be preserved for a long time. Studies of these zircon minerals has given us clues about the Hadean environment, and the formation and evolution of Earth's oldest crust. The zircons' chemistry suggests that they formed in magmas produced by the melting of sediments deposited at the bottom of an ancient ocean. This suggests that the zircons are evidence that the Hadean Eon cooled rapidly, and liquid water oceans were formed early on. Other research on the Hadean zircons suggests that the Earth's earliest crust was mafic (rich in magnesium and iron). Until recently, however, the existence of that crust remained to be confirmed. In 2008, a study led by one of us - associate professor Jonathan O'Neil (then a McGill University doctoral student) - proposed that rocks of this ancient crust had been preserved in northern Québec and were the only known vestige of the Hadean. Since then, the age of those rocks - found in the Nuvvuagittuq Greenstone Belt - has been controversial and the subject of ongoing scientific debate. 'Big, old solid rock' The Nuvvuagittuq Greenstone Belt is located in the northernmost region of Québec, in the Nunavik region above the 55th parallel. Most of the rocks there are metamorphosed volcanic rocks, rich in magnesium and iron. The most common rocks in the belt are called the Ujaraaluk rocks, meaning "big old solid rock" in Inuktitut. The age of 4.3 billion years was proposed after variations in neodymium-142 were detected, an isotope produced exclusively during the Hadean through the radioactive decay of samarium-146. The relationship between samarium and neodymium isotope abundances had been previously used to date meteorites and lunar rocks, but before 2008 had never been applied to Earth rocks. This interpretation, however, was challenged by several research groups, some of whom studied zircons within the belt and proposed a younger age of at most 3.78 billion years, placing the rocks in the Archean Eon instead. Confirming the Hadean Age In the summer of 2017, we returned to the Nuvvuagittuq belt to take a closer look at the ancient rocks. This time, we collected intrusive rocks - called metagabbros - that cut across the Ujaraaluk rock formation, hoping to obtain independent age constraints. The fact that these newly studied metagabbros are in intrusion in the Ujaraaluk rocks implies that the latter must be older. The project was led by masters student Chris Sole at the University of Ottawa, who joined us in the field. Back in the laboratory, we collaborated with French geochronologist Jean-Louis Paquette. Additionally, two undergraduate students - David Benn (University of Ottawa) and Joeli Plakholm (Carleton University) participated to the project. We combined our field observations with petrology, geochemistry, geochronology and applied two independent samarium-neodymium age dating methods, dating techniques used to assess the absolute ages of magmatic rocks, before they became metamorphic rocks. Both assessments yielded the same result: the intrusive rocks are 4.16 billion years old. The oldest rocks Since these metagabbros cut across the Ujaraaluk formation, the Ujaraaluk rocks must be even older, placing them firmly in the Hadean Eon. Studying the Nuvvuagittuq rocks, the only preserved rocks from the Hadean, provides a unique opportunity to learn about the earliest history of our planet. They can help us understand how the first continents formed, and how and when Earth's environment evolved to become habitable. (Disclaimer Statement: Hanika Rizo receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC). Jonathan O'Neil receives funding from the Natural Sciences and Engineering Research Council of Canada.)
Yahoo
03-07-2025
- Science
- Yahoo
A Fragment of Earth's Original Crust Still Exists—and It's Buried in Canada
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn in this story: What are now thought to be the oldest rocks on Earth have been confirmed to have an age of almost 4.2 billion years, almost as old as the planet itself. Researchers were met with controversy for their initial claims, but dating isotopes of one metal that decayed into another showed that the igneous rock from northeastern Canada really was that old. This ancient piece of our planet could tell us more about its turbulent past. Earth is about 4.5 billion years old, and as the eons passed, the crust of the young planet experienced turbulence. Asteroid collisions shattered some parts, which melted and recrystallized, while tectonic plates constantly shifted and triggered volcanic eruptions that oozed magma over the surface. Erosion further erased evidence of our planet's early scars. The most ancient layers of crust were all but lost—until now. The oldest crust on our planet formed during what is known as the Hadean epoch. Reaching back to the period between 4.6 to 4 billion ago, this was when the Solar System was still forming in a thick haze of gas and dust (possibly the refuse from a supernova) that surrounded the nascent Sun. It is an epoch not even considered part of geologic time because, for years, the only rocks found dating back from this period were meteorites that fell from space. Hadean meteorites and lunar rocks up to 4.5 billion years old have been found before, but nothing directly from Earth even came close. As Earth became covered in swaths of ocean, layers of soil and landscapes as diverse as forests, deserts, mountains, volcanic plains, glaciers, grasslands and cities built by humans, primordial relics were buried even deeper. Anything found to have been part of our planet's crust in the distant past was 3.8 billion years old or younger. That puts even our latest findings in the Archean period, which followed the Hadean. Geologist Jonathan O'Neil of Ottawa University in Canada refused to believe there were no Hadean fragments of crust remaining. While zircons found embedded in Australian rocks were successfully dated back to that period, an actual piece of crust that old had never surfaced. In a controversial 2008 study, O'Neil and his research team claimed that they had discovered a part of the original crust in northeast Canada's remote Nuvvuagittuq Greenstone Belt. This formation has stayed intact almost since Earth was born. It could be a portal into Earth's earliest growing pains. There was just one problem. Another group of researchers steadfastly argued that the rocks of the Nuvvuagittuq Greenstone Belt were no older than 3.8 billion years. While the 4-billion-year-old rocks of the Acasta gneiss in the northwest of Canada were slightly older, having just barely formed at the end of the Hadean, they were still not old enough. O'Neil was determined to prove that the Nuvvuagittuq rock, originally a flood plain of magma that hardened into volcanic basalt, predated the other pieces of crust. It turned out that the evidence was hiding in the rock itself, and not in the form of zircons. When they first formed, they had contained samarium, a metal which oxidizes when exposed to air. Any samarium in the rocks was long gone. However, samarium isotopes had left behind chemical signatures of their decay into isotopes of neodymium. Two different isotopes of neodymium which had come from two samarium isotopes were both dated to 4.16 billion years. 'The age agreement between both extant and extinct radiogenic systems, in rocks related through igneous fractionation, is compelling evidence for preservation of Hadean rocks in the Nuvvuagittuq Greenstone Belt, opening a rare window into Earth's earliest times,' O'Neil and his colleagues said in a study recently published in Science. There could be more crust that ancient which has not been unearthed yet. It is even possible that some may have landed on the Moon. 4.4 billion years ago, not long after Earth formed, an extreme collision shattered part of the Earth and formed our only satellite, which has not been explored by humans since the Apollo Era. What future Artemis astronauts find once we return to the Moon might give us more insight about how our planet grew up. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
TimesLIVE
01-07-2025
- Science
- TimesLIVE
Rocks in Canada's Quebec province found to be the oldest on Earth
The researchers applied two dating methods based on an analysis of the radioactive decay of the elements samarium and neodymium contained in them. They produced the same conclusion, that the rocks were 4.16-billion years old. Future chemical analyses of the rocks could provide insight into Earth's conditions during the Hadean, a time shrouded in mystery because of the paucity of physical remains. 'The 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. The rain would have been composed of water evaporated from Earth's primordial seas. 'Since some of the rocks were also formed from precipitation from ancient seawater, they can shed light on temperatures and the first oceans' composition and help establish the environment where life could have begun on Earth,' O'Neil said. Until recently, 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 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. However, by the time the Nuvvuagittuq rocks formed, Earth had begun to become a more recognisable place. 'The Earth was 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 existed on Earth, likely mostly basaltic and covered with shallow and warmer oceans. An atmosphere was present, but different from the present day atmosphere,' O'Neil said. There had been some controversy over the age of the 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-billion 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 the 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.'
