66 years ago

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Geologists Find Clues In Crater Left By Dinosaur-Killing Asteroid

by Goeff Brumfiel / NPR

Scientists have had a literal breakthrough off the coast of Mexico.

After weeks of drilling from an offshore platform in the Gulf of Mexico, they have reached rocks left over from the day the Earth was hit by a killer asteroid.

The cataclysm is believed to have wiped out the dinosaurs. “This was probably the most important event in the last 100 million years,” says Joanna Morgan, a geophysicist at Imperial College in London and a leader of the expedition.

Since the 1980s, researchers have known about the impact site, located near the present-day Yucatan Peninsula. Known as Chicxulub, the crater is approximately 125 miles across. It was created when an asteroid the size of Staten Island, N.Y., struck Earth around 66 million years ago. The initial explosion from the impact would have made a nuclear bomb look like a firecracker. The searing heat started wildfires many hundreds of miles away.

After that, came an unscheduled winter. Sulfur, ash and debris clouded the sky. Darkness fell and, for a while, Earth was not itself.

“I think it was a bad few months, really,” Morgan says.

That’s an understatement: Scientists believe 75 percent of life went extinct during this dark chapter in Earth’s history, including the dinosaurs.

Researchers have sampled Chicxulub before, but this expedition by the European Consortium for Ocean Research Drilling precisely targets a key part of the crater yet to be studied: a ring of mountains left by the asteroid.

Read the entire article

Parasaurolophus with little ones in gouache paint. Better against icy blue-grey than my earlier photo on black.

Why dinosaurs? I wanted to do an art project focusing on life from Earth’s distant past. 4.6 billion years of our planet’s history is a huge topic, so I decided to narrow the project down to the Mesozoic Era, spanning 252-66 million years ago. Dinosaurs are well known, so I thought it would be good to paint prehistoric creatures that people are at least a little familiar with.

Check out this incredible shot of the Old Harry Rocks in Dorset, England. These rock formations consist of chalk stalks were formed approximately 66 million years ago that have gradually eroded and collapsed over the centuries.

Photo by Jack Boothby

Learn more about our book here: http://amzn.to/2aND71C

This image depicts how the Chicxulub crater, on Mexico’s Yucatán Peninsula, may have looked in the aftermath of the asteroid impact that killed off the dinosaurs 66 million years ago.

This spring, researchers are drilling into “ground zero” of the impact to understand how life came back.

Today, we’ve compiled a few basic dinosaur facts for you to enjoy:

  • Dinosaurs are a group of reptiles that have lived on Earth for about 245 million years.
  • In 1842, the English naturalist Sir Richard Owen coined the term Dinosauria, derived from the Greek deinos, meaning “fearfully great,” and sauros, meaning “lizard.”
  • Dinosaur fossils have been found on all seven continents.
  • All non-avian dinosaurs went extinct about 66 million years ago.
  • There are roughly 700 known species of extinct dinosaurs.
  • Modern birds are a kind of dinosaur because they share a common ancestor with non-avian dinosaurs.

Share these with someone you think needs to know more about dinos and learn much more on the Museum website

AMNH/D.Finnin

WHAT REALLY KILLED THE DINOSAURS?

For decades the reason behind the extinction of the seemingly indestructible dinosaurs baffled scientists. It proved challenging to formulate a theory that explained the disappearance of almost 75% of the earths species, including all dinosaurs, yet it was even harder to find out why smaller animals survived whilst most weighing more than 50 pounds perished. 

In the 1980’s a team proposed a outlandish theory that the dinosaurs met their end via extra-terrestrial means, a meteor. The theory was met by heavy criticism, surely a rock large enough to wipe out most life of earth would have left quite a scar in the earths surface? It wasn’t until 1990 a 110 mile crater in diameter was found in the gulf of Mexico, providing evidence for the theory. Over the years even more evidence has mounted and today it is generally accepted that 66 million years ago a huge rock hurled into the earth delivering an impact with more energy than a billion atomic bombs, this explosive event wiped out the dinosaurs. However the impact itself did not do the most damage, it is what it set in motion….

IMPACT
The sheer impact of the meteor itself would have devastated anything in its path, vaporising any unfortunate animal for miles around. The enormous force generated by the rock crashing into the earth would have sent shockwaves hurtling out in all directions.
SHOCKWAVES
The shockwaves could arguably have done the most damage. As they travelled for miles at high speed, through land and water they would have set in motion megatsunamis thousands of metres high and shattering earthquakes that thundered through the earths crust.
MEGATSUNAMIS
The shockwaves produced by the impact would have resulting in the largest megatsunamis life on earth may have ever seen. At thousands of metres tall these walls of water would have crashed down far into the land sweeping away anyone in its path and drowning out plant and animal life.
EARTHQUAKES
As shockwaves rippled through the earth with immense speed the earths crust would literally be ripping at the seams resulting in violent volcanic activity across the globe. These eruptions would have spewed out millions of tonnes of ash and noxious gas that blanketed most of the world, choking the atmosphere and polluting the air as well as poisoning drinking water, blocking out the sun and resulting in acid rain.

GLOBAL FIRE
Millions of square miles across the planet would have been engulfed in flames. The humid, warm world of the cretaceous would have swept fire across the globe incinerating anything trapped in the forests.
DEATH OF PLANT LIFE
With little water and no sun, photosynthesis was impossible, not to mention acid rain tearing through organic plant material. With the death of the plants came the collapse of the food chain, the herbivores starved and when they fell the carnivores swiftly followed.

The Earth was swept into winter, choking on toxic gases and burning alive. It would take millions of years to recover, but all was not lost, smaller animals would be able to sustain themselves and ride out this difficult time. The dinosaurs would not make it but mammals would be victorious repopulate the planet with weird and wonderful new beings.

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When a 6-mile-wide asteroid struck Earth 66 million years ago, it wreaked havoc, showering the planet in hot clouds of sulfur and ash, completely changing the climate and wiping about 75% of the species on Earth at the time. The impact is what likely caused the dinosaurs to go extinct.

We don’t know a lot about this cataclysmic event or how life managed to make a comeback.

Now, after weeks of drilling down into a rock slab in the Gulf of Mexico, a team of scientists has reached the impact crater that the dinosaur-killing asteroid left behind. The rock samples from the crater could teach us a lot about this violent period in Earth’s history.

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bbc.com
Dinosaurs 'in decline' 50 million years before asteroid strike
The dinosaurs were already in decline 50 million years before the asteroid strike that finally wiped them out, a study suggests.

The dinosaurs were already in decline 50 million years before the asteroid strike that finally wiped them out, a study suggests.

The new assessment adds further fuel to a debate on how dinosaurs were doing when a 10km-wide space rock slammed into Earth 66 million years ago.

A team suggests the creatures were in long-term decline because they could not cope with the ways Earth was changing.

The study appears in PNAS journal.

Researchers analysed the fossil remains of dinosaurs from the point they emerged 231 million years ago up to the point they went extinct.

To begin with, new species evolved at an explosive rate. But things started to slow about 160 million years ago, leading to a decline in the number of species which commences at about 120 million years ago.

Dr Manabu Sakamoto, a palaeontologist from the University of Reading, who led the research, said: “We were not expecting this result.”

“Even though they were wiped out ultimately by the impact of the asteroid, they were actually already on their way out around 50 million years before the asteroid hit.”

Continue Reading.

youtube

How many mass extinctions have there been? 

Everything that lives must die. It’s just the way life’s cookie of crumbles, at least until science figures out a way to make immortal cookies. Add up enough of those deaths, and a whole species might go extinct. This is also a natural part of life and death on Earth, and happens at a pretty steady rate. 

But sometimes, if enough species go extinct in a short period of time (here, “short period of time” can be anywhere from hundreds of thousands to millions of years) then scientists declare it a mass extinction. The most famous of these, sparked by a giant space rock hitting Earth ~66 million years ago, killed off all the dinosaurs that weren’t destined to become birds and allowed mammals to take over the globe. 

But how many mass extinctions have their been throughout Earth’s history? That’s the question tackled in the most recent video from our friends at MinuteEarth. The most commonly cited tally of mass extinctions is five, but as with most things in science, this number gets a little more uncertain the deeper that we dig. This is because most of what we know about mass extinctions comes from actual digging.

The main tool we have for reconstructing what was alive or dead at any time in Earth’s history is the rocky remains those creatures leave behind. Earth’s most recent big death, the dino-killer, is pretty easy to see in the fossil record, because it happened not that long ago (so the fossils are near the top) and dinosaurs were full of bones (so they fossilize better than, say, jellyfish). 

But as we go back into deep time, we often find fewer fossils (either because creatures had soft bodies or because the rock layers they reside in aren’t easy for us to access) or the the fossils provide a skewed census of what was alive (some environments, like muddy swamps and shallow seas, are more likely to create fossils than open land). There may have been times way back in Earth’s history when huge numbers of microbes died, for instance, but how would we know? Bacteria don’t fossilize real well (although it can happen!)

So while we know of five times that a lot of species definitely died in a “short” period of time, we can’t be sure that there were only five times when this happened. 

What we can be pretty sure of is that Earth is now in the early stages of another massive die-off, and this modern mass extinction is primarily our fault. Using the classical numbering system, we call this one the Sixth Mass Extinction, but however you decide to tally it up, it’s a big deal:

The Cretaceous-Paleogene Extinction

The most recent mass extinction event is also likely the best understood of the Big Five. The Cretaceous-Paleogene extinction event was triggered by a massive asteroid impact 66 million years ago. 

In addition to its most famous victims, the non-avian dinosaurs, the K-Pg event caused the extinction of pterosaurs and extinguished many species of early mammals and a host of amphibians, birds, reptiles, and insects. Life in the seas was also badly disrupted, with damage to the oceans causing the extinction of marine reptiles like mosasaurs and plesiosaurs, as well as of ammonites, then one of the most diverse families of animals on the planet.

In all, scientists estimate that 75 percent of species living at the time of the K-Pg extinction were wiped out.

Learn about five other mass extinction events. 

Jiangxisaurus ganzhouensis

Source: http://en.wikipedia.org/wiki/Jiangxisaurus

Name: Jiangxisaurus ganzhouensis

Name Meaning: Jiangxi Province Lizard 

First Described: 2013

Described By: Wei et al. 

ClassificationDinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoriformes, Maniraptora, Pennaraptora, Oviraptorosauria, Caenagnathoidea, Oviraptoridae, Ingeniinae

We have two dinosaurs today because somehow I missed this one when I was making my schedule. Our second to last oviraptor, Jiangxisaurus lived in the Campanian to Maastrichtian ages of the Late Cretaceous, from 72 to 66 million years ago. It was found in the Nanxiong FOrmation in Ganzhou City, Jiangxi Province, Southern China, giving it its name. It had a frailer mandible than the similar Heyuannia, as well as more strongly curved claws. It lived alongside many other dinosaurs and comes from a formationw here many footprints and egg shells have been found. It lived alongside Gannansaurus, Microhadrosaurus, Nanshiungosaurus, Tarbosaurus, Banji and Ganzhousaurus.

Shout out goes to isntshelovely-bbw!

Why did the dinosaurs die?

About 66 million years ago the Cretaceous–Paleogene (K–Pg) extinction event wiped out about 80% of life on Earth, and no one is exactly sure what caused it. Here’s a list of the current theories though!

  1. Asteroid/comet – metal and rock/ ice, dust, rocky materials and organic compounds
  2. Global firestorm (caused by asteroid)
  3. Hypercanes, also known as giant giant hurricanes, which not only devastated those who came in their paths but also were high enough to damage the ozone layer
  4. Gradual extinction and competition with mammals (aka the boring theory)
  5. Continental drift, which changed habitats and climates as ocean patterns changed
  6. Sea level changes
  7. Disease
  8. Volcanoes spewing sulfur for 10,000 years
  9. Any of these combining in a short amount of time
Anzu wyliei

By Sam Stanton on @artisticthingem

Name: Anzu wyliei

Name Meaning: Wylie’s feathered demon 

First Described: 2014

Described By: Lamanna et al. 

ClassificationDinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoriformes, Maniraptora, Pennaraptora, Oviraptorosauria, Caenagnathoidea, Caenagnathidae, Caenagnathinae 

Anzu is a recently discovered Caenagnathid that was discovered this past year, famously dubbed “the chicken from hell.” It lived 66 million years ago, in the Maastrichtian age of the Late Cretaceous. It was about 3 to 3.5 meters long and 1.5 meters tall. It is the largest known oviraptor from North America, and the first well-preserved oviraptor known from North America. It was found in the Maastrichtian Hell Creek Formation of Montana and South Dakota. It had a huge crest on its skull, no teeth, and was extremely bird like. It was probably a sister species of Caenagnathus, and was probably an omnivore or an herbivore. It lived in an ancient floodplain, which is very different from the environment Asian oviraptors lived in: semi-arid or arid. It was a fast runner, and probably was a generalist. It probably used its crest for display between members of the species. 

Source: 

http://en.wikipedia.org/wiki/Anzu_(dinosaur)

Shout out goes to malazan-warren-mastermage!

telegraph.co.uk
Earth has entered sixth mass extinction, warn scientists
Humans are responsible for so many species dying out that we are now in a sixth mass extinction, Stanford University has warned

Earth has entered its sixth mass extinction with animals now dying out at 100 times the normal rate, scientists have warned.

Humans have created a toxic mix of habitat loss, pollution and climate change, which has already led to the loss of at least 77 species of mammals, 140 types of bird since and 34 amphibians since 1500.

They include creatures like the dodo, Steller’s Sea Cow, the Falkland Islands wolf, the quagga, the Formosan clouded leopard, the Atlas bear, the Caspian tiger and the Cape lion.

Scientists at Stanford University in the US claim it is the biggest loss of species since the Cretaceous-Tertiary mass extinction which wiped out the dinosaurs 66 million years ago.“Without any significant doubt that we are now entering the sixth great mass extinction event,“ said Professor Paul Ehrlich, at the Stanford Woods Institute for the Environment.

“Species are disappearing up to about 100 times faster than the normal rate between mass extinctions, known as the background rate. “Our calculations very likely underestimate the severity of the extinction crisis. There are examples of species all over the world that are essentially the walking dead.”Using fossil records and extinction counts from a range of sources, the researchers calculated the normal ‘background rate’ of extinctions and compared it with a conservative estimate of current extinctions.

Natural population changes in the wild usually lead to two species of mammals dying out every 10,000 years. But the current rate is 114 times that level.
And humans have been responsible for animal decline going much further back. In the islands of tropical Oceania, up to 1800 bird species are estimated to have gone extinct in the last 2,000 years.

It is likely that early humans were also responsible for wiping out the huge megafauna which used to live in Australia including a huge giant wombat a marsupial lion and a flesh-eating kangaroo. Currently one in four mammals is at risk of going extinct and 41 per cent of amphibians. Many now only survive in captivity.

(excerpt - click the link for the complete article)