A geologic change might have plunged lush landscapes into arid zones, killing off an array of creatures—and it might happen again one day.

AT FIRST, IT seems like a case of extinction by climate change: More than 160 million years ago, during the Jurassic period, a fanciful menagerie crept, swam, and flew through the cool, damp forests of what is now northeastern China. Then, almost in a geologic instant, the air grew warmer and the land dried out. As the water disappeared, so too did the life. And yet, researchers have struggled to pin down a climate-related culprit behind this ecological collapse.

Now, a study published in the journal Geology suggests that it wasn’t the climate that changed, but the geographic location of the landscape. Paleomagnetic signatures in the area’s rocks indicate that sometime between 174 and 157 million years ago, the whole region shifted southward by a startling 25 degrees, plunging once lush landscapes into zones of desiccating heat.

The ancient rocky lurch was part of a phenomenon known as true polar wander, in which the topmost layers of the planet, likely all the way down to the liquid outer core, rotate significantly even as Earth continues its daily turn around its usual spin axis.

In the Jurassic, the surface and mantle made this twist around an imaginary line through the crook in Africa’s west coast known as the Bight of Benin. The change would have been massive: If a similar shift were to happen today, a flag planted in Dallas, Texas, would end up where Northern Manitoba, Canada, currently sits. On the other side of the world, the continent of Asia would soar southward.

JURASSIC CLIMATE SHIFT
More than 160 million years ago, northeastern China was home to a wide array of plants and animals known as the Yanliao Biota. A dramatic change in climate from temperate to arid conditions likely led to their demise. But what drove this shift has long been a mystery.

Earth’s monster jump
A new study of paleomagnetic data from northeastern China suggests that between 174 and 157 million years ago, the entire surface of Earth rotated a staggering 25 degrees, which would have moved the landscape inhabited by the Yanliao Biota from a cool, humid zone into a hot, dry band.

How did this happen?
This colossal change can be explained by true polar wander, which occurs when a mass imbalance causes the entire surface of Earth and its mantle to rotate around the core. While true polar wander has likely occurred throughout the planet’s history, this ancient event was particularly drastic.

Earth has likely experienced smaller amounts of true polar wander throughout its past, and some scientists think it continues today.

“We’re experiencing true polar wander as we speak,” says Dennis Kent, a paleomagnetist at both Rutgers and Columbia University who wasn’t part of the new study team.

To be clear, these more recent forays are not the source of modern-day climate change, which is driven by humans’ relentless release of greenhouse gasses into the atmosphere. In addition, the magnitude of this Jurassic shift—and whether true polar wander is even a real phenomenon—remain under debate.

The results suggest that the Jurassic surface rotated by at least 6.7 inches each year, which led to the slow drying of the East Asian landscape that likely killed off many of the region’s ancient plants and animals known as the Yanliao Biota. Past studies hint that another smaller wander around 130 million years ago returned East Asia to temperate climes, setting the stage for the rise of a burst of life known as the Jehol Biota. These exceptionally preserved fossils have yielded many startling finds, including the discovery of the first known feathered dinosaur that was not directly related to birds.

https://www.nationalgeographic.com/science/2019/11/earths-odd-rotation-may-solve-ancient-climate-mystery/

PermeateFree said:

A geologic change might have plunged lush landscapes into arid zones, killing off an array of creatures—and it might happen again one day.

AT FIRST, IT seems like a case of extinction by climate change: More than 160 million years ago, during the Jurassic period, a fanciful menagerie crept, swam, and flew through the cool, damp forests of what is now northeastern China. Then, almost in a geologic instant, the air grew warmer and the land dried out. As the water disappeared, so too did the life. And yet, researchers have struggled to pin down a climate-related culprit behind this ecological collapse.

Now, a study published in the journal Geology suggests that it wasn’t the climate that changed, but the geographic location of the landscape. Paleomagnetic signatures in the area’s rocks indicate that sometime between 174 and 157 million years ago, the whole region shifted southward by a startling 25 degrees, plunging once lush landscapes into zones of desiccating heat.

The ancient rocky lurch was part of a phenomenon known as true polar wander, in which the topmost layers of the planet, likely all the way down to the liquid outer core, rotate significantly even as Earth continues its daily turn around its usual spin axis.

In the Jurassic, the surface and mantle made this twist around an imaginary line through the crook in Africa’s west coast known as the Bight of Benin. The change would have been massive: If a similar shift were to happen today, a flag planted in Dallas, Texas, would end up where Northern Manitoba, Canada, currently sits. On the other side of the world, the continent of Asia would soar southward.

JURASSIC CLIMATE SHIFT
More than 160 million years ago, northeastern China was home to a wide array of plants and animals known as the Yanliao Biota. A dramatic change in climate from temperate to arid conditions likely led to their demise. But what drove this shift has long been a mystery.

Earth’s monster jump
A new study of paleomagnetic data from northeastern China suggests that between 174 and 157 million years ago, the entire surface of Earth rotated a staggering 25 degrees, which would have moved the landscape inhabited by the Yanliao Biota from a cool, humid zone into a hot, dry band.

How did this happen?
This colossal change can be explained by true polar wander, which occurs when a mass imbalance causes the entire surface of Earth and its mantle to rotate around the core. While true polar wander has likely occurred throughout the planet’s history, this ancient event was particularly drastic.

Earth has likely experienced smaller amounts of true polar wander throughout its past, and some scientists think it continues today.

“We’re experiencing true polar wander as we speak,” says Dennis Kent, a paleomagnetist at both Rutgers and Columbia University who wasn’t part of the new study team.

To be clear, these more recent forays are not the source of modern-day climate change, which is driven by humans’ relentless release of greenhouse gasses into the atmosphere. In addition, the magnitude of this Jurassic shift—and whether true polar wander is even a real phenomenon—remain under debate.

The results suggest that the Jurassic surface rotated by at least 6.7 inches each year, which led to the slow drying of the East Asian landscape that likely killed off many of the region’s ancient plants and animals known as the Yanliao Biota. Past studies hint that another smaller wander around 130 million years ago returned East Asia to temperate climes, setting the stage for the rise of a burst of life known as the Jehol Biota. These exceptionally preserved fossils have yielded many startling finds, including the discovery of the first known feathered dinosaur that was not directly related to birds.

https://www.nationalgeographic.com/science/2019/11/earths-odd-rotation-may-solve-ancient-climate-mystery/

> sometime between 174 and 157 million years ago, the whole region shifted southward by a startling 25 degrees

How far and fast did India move north after the splitting up of Gondwana? In that ballpack, or half as fast?

mollwollfumble said:

PermeateFree said:

A geologic change might have plunged lush landscapes into arid zones, killing off an array of creatures—and it might happen again one day.

AT FIRST, IT seems like a case of extinction by climate change: More than 160 million years ago, during the Jurassic period, a fanciful menagerie crept, swam, and flew through the cool, damp forests of what is now northeastern China. Then, almost in a geologic instant, the air grew warmer and the land dried out. As the water disappeared, so too did the life. And yet, researchers have struggled to pin down a climate-related culprit behind this ecological collapse.

Now, a study published in the journal Geology suggests that it wasn’t the climate that changed, but the geographic location of the landscape. Paleomagnetic signatures in the area’s rocks indicate that sometime between 174 and 157 million years ago, the whole region shifted southward by a startling 25 degrees, plunging once lush landscapes into zones of desiccating heat.

The ancient rocky lurch was part of a phenomenon known as true polar wander, in which the topmost layers of the planet, likely all the way down to the liquid outer core, rotate significantly even as Earth continues its daily turn around its usual spin axis.

In the Jurassic, the surface and mantle made this twist around an imaginary line through the crook in Africa’s west coast known as the Bight of Benin. The change would have been massive: If a similar shift were to happen today, a flag planted in Dallas, Texas, would end up where Northern Manitoba, Canada, currently sits. On the other side of the world, the continent of Asia would soar southward.

JURASSIC CLIMATE SHIFT
More than 160 million years ago, northeastern China was home to a wide array of plants and animals known as the Yanliao Biota. A dramatic change in climate from temperate to arid conditions likely led to their demise. But what drove this shift has long been a mystery.

Earth’s monster jump
A new study of paleomagnetic data from northeastern China suggests that between 174 and 157 million years ago, the entire surface of Earth rotated a staggering 25 degrees, which would have moved the landscape inhabited by the Yanliao Biota from a cool, humid zone into a hot, dry band.

How did this happen?
This colossal change can be explained by true polar wander, which occurs when a mass imbalance causes the entire surface of Earth and its mantle to rotate around the core. While true polar wander has likely occurred throughout the planet’s history, this ancient event was particularly drastic.

Earth has likely experienced smaller amounts of true polar wander throughout its past, and some scientists think it continues today.

“We’re experiencing true polar wander as we speak,” says Dennis Kent, a paleomagnetist at both Rutgers and Columbia University who wasn’t part of the new study team.

To be clear, these more recent forays are not the source of modern-day climate change, which is driven by humans’ relentless release of greenhouse gasses into the atmosphere. In addition, the magnitude of this Jurassic shift—and whether true polar wander is even a real phenomenon—remain under debate.

The results suggest that the Jurassic surface rotated by at least 6.7 inches each year, which led to the slow drying of the East Asian landscape that likely killed off many of the region’s ancient plants and animals known as the Yanliao Biota. Past studies hint that another smaller wander around 130 million years ago returned East Asia to temperate climes, setting the stage for the rise of a burst of life known as the Jehol Biota. These exceptionally preserved fossils have yielded many startling finds, including the discovery of the first known feathered dinosaur that was not directly related to birds.

https://www.nationalgeographic.com/science/2019/11/earths-odd-rotation-may-solve-ancient-climate-mystery/

> sometime between 174 and 157 million years ago, the whole region shifted southward by a startling 25 degrees

How far and fast did India move north after the splitting up of Gondwana? In that ballpack, or half as fast?

In the history of continental drift, India has been a mysterious record-holder.

More than 140 million years ago, India was part of an immense supercontinent called Gondwana, which covered much of the Southern Hemisphere. Around 120 million years ago, what is now India broke off and started slowly migrating north, at about 5 centimeters per year. Then, about 80 million years ago, the continent suddenly sped up, racing north at about 15 centimeters per year — about twice as fast as the fastest modern tectonic drift. The continent collided with Eurasia about 50 million years ago, giving rise to the Himalayas.

For years, scientists have struggled to explain how India could have drifted northward so quickly. Now geologists at MIT have offered up an answer: India was pulled northward by the combination of two subduction zones — regions in the Earth’s mantle where the edge of one tectonic plate sinks under another plate. As one plate sinks, it pulls along any connected landmasses. The geologists reasoned that two such sinking plates would provide twice the pulling power, doubling India’s drift velocity.

https://news.mit.edu/2015/india-drift-eurasia-0504#:~:text=Around%20120%20million%20years%20ago,the%20fastest%20modern%20tectonic%20drift.

> the Jurassic surface rotated by at least 6.7 inches each year

> India … racing north at about 15 centimeters per year

6.7 inches each year is 17 centimetres per year.

So pretty much the same. Thank you.