Latest news with #AibingLi
Yahoo
08-04-2025
- Science
- Yahoo
Great Lakes basins may have formed millions of years ago from activity deep in the Earth — long before glaciers, study finds
CHICAGO — As an ice sheet thousands of feet thick began its final crawling retreat from North America to the Arctic toward the end of the last glacial period some 10,000 years ago, it left behind the planet's largest freshwater system. At least that's what scientists have long believed about the formation of the Great Lakes. But a recent study suggests that the timeline actually stretches further back — beyond the evolution of early humans and past the age of dinosaurs — to 200 to 300 million years ago when a hot spot, or plume of hot material, from underneath Earth's crust created a low point that the glaciers would finish carving out and filling with water much later. 'Most of upper North America was covered by glaciation. But why, in this particular area, (are there) these Great Lakes?' said Aibing Li, a seismologist at the University of Houston who co-authored the study, which was published in the scientific journal Geophysical Research Letters in December. 'We'll see this surface feature, and we usually just consider that's just some very shallow process. It could have, actually, some deeper source, a deeper origin. It's not just like, randomly, on the surface, you have something special. Anything that happened in that area must have some reason.' The continents, as they are today, didn't exist all those hundreds of millions of years ago until the supercontinent Pangaea broke. As North America shifted away, the site of the modern-day Great Lakes passed over the Cape Verde hot spot, Li found. When ocean hot spots interact with the planet's surface, it usually results in volcano chains like in Hawaii. But when these hot spots are located within a continent, the impact is more difficult for scientists to detect through the rigid, thick outermost layer of Earth. So, Li wasn't really expecting to find what she did. As they used a model to study seismic movements in the country's northeast, her team noticed that earthquake waves under the crust there traveled at different velocities, horizontally and vertically. 'We actually were puzzled, at the beginning, with what we saw,' she said. Upon closer inspection, they realized the plate movements indicated that the hot spot — now under an African island nation of the same name located in the central Atlantic Ocean — had sat for a long time right below what would later become the eastern part of the lakes, specifically lakes Huron, Erie and Ontario. Li explained that as hot, buoyant material from a hot spot plume rises under a continent, it finds resistance from the thick outer layer. 'It'll lift, push upward,' Li said. 'It tries to escape.' Since the last major ice age started 2.7 million years ago and until it ended about 12,000 years ago, the Laurentide Ice Sheet in North America expanded and melted between several millennia of cold and warm periods. This allowed the glacier to finish shaping the massive bodies of water. Maureen Long, a seismologist and professor of Earth and planetary sciences at Yale University, said the study contributes to scientific discussion about how natural geographical features can be affected by processes deep below. 'It is a hypothesis that still needs to be tested, but it really does illuminate the connection between what happens in the deep Earth and what we see at the surface,' Long said. 'And whether or not this particular hypothesis turns out to be right, that connection … is very real, so this is a really important line of research.' Long, an expert in mantle dynamics in the northeast United States, also believes like Li that there has to be a reason for the Great Lakes to be located where they are. '(It's) very simple physics. If you fill something with water, the water is going to go to the low point,' Long said. 'The more recent glaciation formed the actual lakes and filled them — that part is relatively well understood. The part that we're still puzzling over is, why was there sort of this low point there in the first place that then got carved out by the glaciers?' While Li plans to soon find out if lakes Michigan and Superior could've also been created in the same way as their eastern counterparts, she hopes the study encourages more scientific research into the formation of inland water bodies besides the Great Lakes. 'When you have a new idea, it's not easy (for it) to be accepted,' Li said. 'But I think this can stimulate some more discussions. And science always evolves.' Long said the study illustrates the concept of geologic time, which humans don't often think of as they go about their day-to-day lives on timescales of minutes and hours. 'The features that we see, mountains or lakes or rivers, those features get shaped over millions to tens of millions to hundreds of millions to billions of years. It's amazing to think about,' Long said. 'The Earth is 4.6 billion years old — that's a lot of time. And we see a snapshot of what the Earth is today, but over that long history and that long timescale, a lot has changed.' ____
Chicago Tribune
08-04-2025
- Science
- Chicago Tribune
Daywatch: When did the Great Lakes basins form?
Good morning, Chicago. As an ice sheet thousands of feet thick began its final crawling retreat from North America to the Arctic toward the end of the last glacial period some 10,000 years ago, it left behind the planet's largest freshwater system. At least that's what scientists have long believed about the formation of the Great Lakes. But a recent study suggests that the timeline actually stretches further back — beyond the evolution of early humans and past the age of dinosaurs — to 200 to 300 million years ago when a hot spot, or plume of hot material, from underneath Earth's crust created a low point that the glaciers would finish carving out and filling with water much later. 'Most of upper North America was covered by glaciation. But why, in this particular area, (are there) these Great Lakes?' said Aibing Li, a seismologist at the University of Houston who co-authored the study, which was published in the scientific journal Geophysical Research Letters in December. 'We'll see this surface feature, and we usually just consider that's just some very shallow process. It could have, actually, some deeper source, a deeper origin. It's not just like, randomly, on the surface, you have something special. Anything that happened in that area must have some reason.' Read the full story from the Tribune's Adriana Pérez. Here are the top stories you need to know to start your day, including the future of fluoride in drinking water, Wrigley Field's goose that flew the coop and a review of 'Boop! The Musical,' which opens on Broadway. RFK Jr. says he plans to tell CDC to stop recommending fluoride in drinking water U.S. Health Secretary Robert F. Kennedy Jr. can't order communities to stop fluoridation, but he can tell the CDC to stop recommending it and work with the EPA to change the allowed amount. Mayor Brandon Johnson still mired in firefighters contract standoff, despite dropping reorganization plan When rank-and-file firefighters joined them to demand a contract last month, the Chicago Teachers Union framed the team-up in powerful terms: 'Two unions. One fight.' Now, with a pending deal for teachers clinched last week, only one of them remains in the ring. Andrew Boutros sworn in as Chicago's U.S. attorney Veteran Chicago lawyer and former federal prosecutor Andrew Boutros was sworn in yesterday as the 42nd U.S. attorney for the Northern District of Illinois. Lawsuit settled in March 2019 air crash that killed Matteson Army captain A settlement ends a lawsuit brought by the family of a U.S. Army captain from Matteson killed in a March 2019 commercial jet crash in Ethiopia. The settlement was reached Sunday night before a trial in the case of the death of Antoine Lewis was scheduled to begin yesterday in federal court in Chicago. Man with knife critically wounded in River North police shooting, authorities say Police shot and critically wounded a man wielding a knife after a chase in River North yesterday afternoon, according to authorities. Two officers were also taken to the hospital but were not injured, sources said. Column: After Wrigley Field's goose flew the coop, the search is on for a new Chicago Cubs rally animal It's not known what caused the goose to leave Wrigley. It might have been the bleacher paparazzi that insisted on taking photos, or the bullpen implosion and fielding mistakes that led to Sunday's loss against the San Diego Padres. The goose, who was nicknamed PGA — 'Pete Goose-Armstrong' — by one bleacherite, was unavailable for comment. And now, the search for a new rally animal to pick up the slack begins, writes Paul Sullivan. Hearing begins on $2.8 billion NCAA settlement, with no indication the plan won't go forward The landmark $2.8 billion settlement that will affect every corner of college athletics in the months ahead got its final hearing yesterday, including athletes who criticized the sprawling plan as confusing — and one that said it undervalued them — and attorneys who said they were concerned about the impacts on campuses across the country. U.S. District Judge Claudia Wilken gave no indication yesterday the complaints have changed her mind, setting the table for the plan to move forward. Hank Haney used to prepare Tiger Woods for the Masters. Now he's back home, teaching amateurs of all levels. In another part of his life, Hank Haney would have been at Augusta National this week. As Tiger Woods' swing coach from 2004-10, he would monitor every one of Woods' swings, looking for tweaks to perfect it while preparing one of the greatest players ever for another run at the Masters. This week, though, finds Haney, 69, far away from golf's most intense spotlight. He's teaching at the new Hank Haney Golf Studio in Deerfield, just a mile or so from his boyhood home. Instead of working with the best of the best, Haney now instructs amateur players of all ages and abilities, ranging from low handicappers to the dreamer who just wants to break 90. Auditorium's 2025-26 dance season includes Ensemble Español and Trinity Irish Dance The Auditorium Theatre, henceforth known simply as The Auditorium, has announced its calendar of dance performances for the 2025-26 season. The five performances, all by female-led dance companies, open in November with Chicago's own Ensemble Español Spanish Dance Theater and conclude next spring with the annual visit by Alvin Ailey American Dance Theater. Column: As circuses change, the Chicago Circus & Performing Arts Festival shows that the magic remains How long has it been since you have been to a circus? Over the last decades, what we once knew has changed, writes Rick Kogan. Much of that has had to do with the shift away from animal acts due to animal rights activism and humane-treatment concerns. More change has come in response to the 'wonders' so easily found on the internet, making theatrical, story-driven performances preferable to one clown bashing another clown. Cirque du Soleil and a few other shows emerged as wildly popular theatrical versions of the circus, where highly skilled human performers reign, and among the liveliest examples of this circus reinvention is available at the Chicago Circus & Performing Arts Festival. What's not to love about Betty Boop, U.S.-based international ambassador? It's a rhetorical question, folks. She cannot be fired, writes Tribune theater critic Chris Jones. Vastly improved from its Chicago tryout — director Jerry Mitchell being a master of the dogged retrofit — 'Boop!' is now a stellar little showcase for its ascendant young star, Jasmine Amy Rogers, who does not let playing a literal cartoon character get in the way of a fully fleshed out performance, as sweet and vulnerable as it is determined and resolute.
Chicago Tribune
08-04-2025
- Science
- Chicago Tribune
Great Lakes basins may have formed millions of years ago from activity deep in the Earth — long before glaciers, study finds
As an ice sheet thousands of feet thick began its final crawling retreat from North America to the Arctic toward the end of the last glacial period some 10,000 years ago, it left behind the planet's largest freshwater system. At least that's what scientists have long believed about the formation of the Great Lakes. But a recent study suggests that the timeline actually stretches further back — beyond the evolution of early humans and past the age of dinosaurs — to 200 to 300 million years ago when a hot spot, or plume of hot material, from underneath Earth's crust created a low point that the glaciers would finish carving out and filling with water much later. 'Most of upper North America was covered by glaciation. But why, in this particular area, (are there) these Great Lakes?' said Aibing Li, a seismologist at the University of Houston who co-authored the study, which was published in the scientific journal Geophysical Research Letters in December. 'We'll see this surface feature, and we usually just consider that's just some very shallow process. It could have, actually, some deeper source, a deeper origin. It's not just like, randomly, on the surface, you have something special. Anything that happened in that area must have some reason.' The continents, as they are today, didn't exist all those hundreds of millions of years ago until the supercontinent Pangaea broke. As North America shifted away, the site of the modern-day Great Lakes passed over the Cape Verde hot spot, Li found. When ocean hot spots interact with the planet's surface, it usually results in volcano chains like in Hawaii. But when these hot spots are located within a continent, the impact is more difficult for scientists to detect through the rigid, thick outermost layer of Earth. So, Li wasn't really expecting to find what she did. As they used a model to study seismic movements in the country's northeast, her team noticed that earthquake waves under the crust there traveled at different velocities, horizontally and vertically. 'We actually were puzzled, at the beginning, with what we saw,' she said. Upon closer inspection, they realized the plate movements indicated that the hot spot — now under an African island nation of the same name located in the central Atlantic Ocean — had sat for a long time right below what would later become the eastern part of the lakes, specifically lakes Huron, Erie and Ontario. Li explained that as hot, buoyant material from a hot spot plume rises under a continent, it finds resistance from the thick outer layer. 'It'll lift, push upward,' Li said. 'It tries to escape.' Since the last major ice age started 2.7 million years ago and until it ended about 12,000 years ago, the Laurentide Ice Sheet in North America expanded and melted between several millennia of cold and warm periods. This allowed the glacier to finish shaping the massive bodies of water. Maureen Long, a seismologist and professor of Earth and planetary sciences at Yale University, said the study contributes to scientific discussion about how natural geographical features can be affected by processes deep below. 'It is a hypothesis that still needs to be tested, but it really does illuminate the connection between what happens in the deep Earth and what we see at the surface,' Long said. 'And whether or not this particular hypothesis turns out to be right, that connection … is very real, so this is a really important line of research.' Long, an expert in mantle dynamics in the northeast United States, also believes like Li that there has to be a reason for the Great Lakes to be located where they are. '(It's) very simple physics. If you fill something with water, the water is going to go to the low point,' Long said. 'The more recent glaciation formed the actual lakes and filled them — that part is relatively well understood. The part that we're still puzzling over is, why was there sort of this low point there in the first place that then got carved out by the glaciers?' We don't know what's at the bottom of the Great Lakes. Climate change demands we find out. While Li plans to soon find out if lakes Michigan and Superior could've also been created in the same way as their eastern counterparts, she hopes the study encourages more scientific research into the formation of inland water bodies besides the Great Lakes. 'When you have a new idea, it's not easy (for it) to be accepted,' Li said. 'But I think this can stimulate some more discussions. And science always evolves.' Long said the study illustrates the concept of geologic time, which humans don't often think of as they go about their day-to-day lives on timescales of minutes and hours. 'The features that we see, mountains or lakes or rivers, those features get shaped over millions to tens of millions to hundreds of millions to billions of years. It's amazing to think about,' Long said. 'The Earth is 4.6 billion years old — that's a lot of time. And we see a snapshot of what the Earth is today, but over that long history and that long timescale, a lot has changed.'
