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3 Billion Years Ago, the World Might Have Been a Waterworld, With No Continents At All – Universe Today

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Evidence from an ancient section of the Earth’s crust suggest that Earth was once a water-world, some three billion years ago. If true, it’ll mean scientists need to reconsider some thinking around exoplanets and habitability. They’ll also need to reconsider their understanding of how life began on our planet.

A new paper presents these results in the journal Nature Geoscience. The title of the paper is “Limited Archaean continental emergence reflected in an early Archaean 18O-enriched ocean.” The co-authors are Boswell Wing of the University of Colorado, Boulder, and his former post-doc student, Benjamin Johnson at Iowa State University.

The work is focused on an area in the Australian Outback called the Panorama district. In that region in northwestern Australia there’s a slab of ocean floor 3.2 billion years old, that’s been turned on its side. The chunk of crust holds chemical clues about ancient Earth’s seawater.

“There are no samples of really ancient ocean water lying around, but we do have rocks that interacted with that seawater and remembered that interaction,” Johnson said in a press release.

“The origin and evolution of Earth’s biosphere were shaped by the physical and chemical histories of the oceans.”

From the paper “Limited Archaean continental emergence reflected in an early Archaean 18O-enriched ocean.

The authors wanted to re-boot the debate over what ancient Earth looked like, and to break new ground in the discussion.

In the introduction to their paper, the two authors say “The origin and evolution of Earth’s biosphere were shaped by the physical and chemical histories of the oceans. Marine chemical sediments and altered oceanic crust preserve a geochemical record of these histories. Marine chemical sediments, for example, exhibit an increase in their 18O/16O ratio through time.” 

Marine sediments have been well-studied over time, but the authors of this study looked at the ancient crust instead. The ancient oceans held different types of oxygen that were then deposited into the crust. The scientists gathered over 100 samples of the ancient rock and analyzed it for two oxygen isotopes: oxygen-16 and oxygen 18. They wanted to find the relative amount of each isotope in the ancient crust, to compare it to the amounts in the sediment.

Artist impression of the early Earth. Credit: NASA Goddard Space Flight Center Conceptual Image Lab
Artist impression of the early Earth. Credit: NASA Goddard Space Flight Center Conceptual Image Lab

Their results showed more oxygen-18 in the crust when it was formed 3.2 billion years ago, meaning the ocean at that time had more oxygen-18. The pair of researchers say that means that when that crust formed, there were no continents. This is because when continents form, they contain clays, and those clays would have absorbed the heavier oxygen-18. So if there had been continents 3.2 billion years ago, their crust samples would have held less oxygen-18.

The over-arching conclusion of their work is that the Earth’s oceans went through two distinct states: one prior to continents forming, and one after continents formed.

Marine chemical sediments have been studied extensively to try to piece together continent formation on ancient Earth. As the study says, those ancient sediments include “carbonates, phosphates, microcrystalline silica and iron oxides. As these minerals form directly from aqueous species, they can reflect the ?18O of the water with which they coexist.” The sediments are like an archival record of Earth at the time, and the older sediments show oxygen-18 values increasing steadily through time, all the way up to today. But this work contrasts with that, and the authors suggest that seawater oxygen-18 decreased through time.

Artist's depiction of a watery exoplanet orbiting a distant red dwarf star. New research indicates that Proxima b could be especially watery. Credit: CfA
Artist’s depiction of a watery exoplanet orbiting a distant red dwarf star. New research indicates that Proxima b could be especially watery. Credit: CfA

The pair of scientists constructed a model for ancient Earth, showing that “the initiation of continental weathering in the late Archaean, between 3 and 2.5 billion years ago, would have drawn down an 18O-enriched early Archaean ocean to ?18O values similar to those of modern seawater.” So only after continents formed, could the oxygen-18 values begin to look like modern values.

Although this study points to the possibility of ancient Earth as a water-world, it doesn’t mean that the planet was without any land-forms. Island-size areas of land, or even micro-continents, may have existed at the time, volcanic in nature, and very rocky. But the types of vast land-forms that cover the Earth today, rich in soil and with tall mountain ranges, may not have existed. If they had, the oxygen-18 content would have more closely resembled today’s.

“There’s nothing in what we’ve done that says you can’t have teeny, micro-continents sticking out of the oceans,” Wing said in a press release. “We just don’t think that there were global-scale formation of continental soils like we have today.”

The authors aren’t suggesting that their work is the definitive piece of evidence in the ongoing discussion around early Earth. They note that their are other possible reasons for their results.

If the ancient continents formed much more slowly than modern continents, that could explain the the discrepancy in oxygen-18. It’s also possible that the clays that absorb oxygen-18 formed in the ocean itself, rather than on the continents.

That points to an enduring mystery in Earth science: when exactly did continents form?

Gondwana 420 million years ago. Image Credit: By Fama Clamosa - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=67001070
Gondwana 420 million years ago. Image Credit: By Fama Clamosa – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=67001070

It’s likely, according to some evidence, that the continents could only form as the Earth’s core shed heat and cooled down. In any case, modern continents didn’t take shape until after the Jurassic. Prior to that, the single super-continent of Gondwana covered about one-fifth of the Earth’s surface. Wing wants to examine younger areas of the Earth’s crust to try to determine more clearly when the modern continents formed.

This study also touches on early life on Earth, and how and when it formed. Earth’s early oceans, much like modern oceans, acted as a buffer, which “mediated climatic feedbacks between the biosphere, atmosphere and geosphere through deep time, helping to ensure long-term planetary habitability.”

In this illustration, the exoplanet GJ 1214 b, a likely ocean world, is shown between Earth and Neptune for comparison. Image Credit: By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), inspired by Thingg's size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8854174
In this illustration, the exoplanet GJ 1214 b, a likely ocean world, is shown between Earth and Neptune for comparison. Image Credit: By Aldaron, a.k.a. Aldaron – Own work, incorporating public domain images for reference planets (see below), inspired by Thingg’s size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8854174

Science has painted a picture of what the early Earth may have looked like, and what the nature of the oceans was. But it’s far from complete. The evidence is all buried, in rock and in time. And as we seek to understand climate change here on Earth, and as we get better and better looks at exoplanets, all these questions about ancient Earth, the oceans, and the biosphere, take on new importance.

As the authors say in their paper, “An early Earth without emergent continents may have resembled a ‘water world’, providing an important environmental constraint on the origin and evolution of life on Earth as well as its possible existence elsewhere.

“The history of life on Earth tracks available niches,” said Wing. “If you’ve got a waterworld, a world covered by ocean, then dry niches are just not going to be available.”

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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