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Posts Tagged ‘Paleontology

NERDS!

A long but very interesting article in the latest National Geographic about the discovery of fossils from a gigantic, swimming dinosaur called Spinosaurus.

This thing appears to have basically been the T Rex of the ancient seas. It was actually ;onger than an adult T Rex, at 16 metre (50 foot) and weighing about seven tonnes. What’s really strange about it though is that it had a large sail on its back and an elongated snout that resembled the maw of a crocodile, with lots of conical teeth.

As is usually the case with dinosaur fossils it turns out that there had been much controversy over exactly what the creature looked like. But things were tougher in this case because the earliest fossils of it – dug up in Egypt between 1910 and 1914 by a Bavarian palaeontologist and aristocrat called Ernst Freiherr Stromer von Reichenbach (sounds like the start of an Indiana Jones movie) – were lost:

During World War II, Allied bombing prompted Stromer—a critic of the Nazi regime—to beg the museum director to move the fossils to safety. The Nazi director refused, and bombing destroyed the fossils in 1944. Drawings, photos, and descriptions in journal articles were all that remained to prove Stromer’s Spinosaurus fossils ever existed.

Chalk up one more piece of barbarity to the moronic Nazis.

This particular fossil has started to put a lot of those questions to rest. It comes from a sandstone formation called the Kem Kem beds, that starts 200 miles east of Marrakesh in Morocco and extends 150 miles to the southwest. It’s rugged, brutally hot country:

I got a taste for the site’s challenges, and the rush of discovery, when I joined the team in July 2019 for a return expedition. The 117-degree heat and arid winds wicked liters of water from my body as we chipped our way through an outcrop marbled like bacon. Fanned along the outcrop below, Ibrahim’s Detroit Mercy students lugged rocks in buckets made from recycled tires and scoured the debris for even the tiniest flecks of bone.

I have to say that this photo struck me as particularly Indiana Jonesish.

But that image is quickly replaced by this passage:

The 2018 dig started brutally. To clear tonnes of sandstone, the crew bought the region’s only working jackhammer. It broke within minutes. Days were so gruelling that several team members were hospitalised once they returned home.

But the promise of discovery kept them going, along with Nutella breaks that temporarily took their minds off the punishing work. Finally, they started finding one caudal vertebra after another from the animal’s tail, sometimes just minutes and inches apart.

The team was so giddy over the bonanza, they drummed out musical beats with their rock hammers and broke into song, belting out, “It’s another caudal!” to the tune of Europe’s “The Final Countdown.”

Heh. Fucking nerds eh? You have to love them. But read the whole article.

Here’s the song they were singling along to. Personally I always hated it as one of those typical over-produced, Big Hair 80’s “rocker classics”. Barf!

See also:

The Fault In Our Stars

Dinosaur Wars and The Nine Foot Problem.

Written by Tom Hunter

May 20, 2021 at 10:17 am

The Fault In Our Stars

And now for something completely different.

Well perhaps not entirely different since it’s a story about mass death.

Last year I wrote an OP about the two great competing theories of what killed the dinosaurs 66 million years ago, and the scientific wars this had sparked through the 1980’s and right up to the present day: Dinosaur Wars and The Nine Foot Problem.

You can read the original piece but to recap: after decades of debate about what killed off the dinosaurs a theory was put forward in 1980 that the culprit was a giant asteroid that hit the earth near today’s Yucatán Peninsula in the Gulf of Mexico. The geological signature of the event is a notebook thick line of rock found around the world called the KT boundary. The crater was finally located in 1990 and is named after a nearby Mexican town, Chixalub, as is the asteroid and sometimes the entire event.

The strongest alternative theory was the Deccan Traps, giant fissure volcanoes in India that spewed out 720,000 cubic miles of lava over hundreds of thousands of years before and after the KT boundary was laid down. No scientist fought for that theory and dismissed the asteroid theory harder than the great Gerta Keller:

… she escaped death three more times: from hepatitis contracted during an Algerian coup she got caught up in, getting shot and badly wounded by an escaping bank robber in Australia, and getting food poisoning in India. She ended up in San Francisco, started studying anthropology and ended up with a PhD in geology at Princeton,

The main point of argument by Keller and others was that there’s no solid evidence of instant, mass death, but a steady decline in dinosaur and other lifeforms up to the KT boundary. 

Then, in just the last few years this long scientific war appeared to be drawing to an close with the discovery, in the Hell Creek formation in Montana, of a site that has preserved not only the day of the asteroid stike but even the hour. A graduate paleontologist, Robert DePalma, has found fossils of dinosaurs mixed in with tektites, small globs of molten rock blasted into the atmosphere by the asteroid that fell back to earth thousands of miles away.

Pretty darned convincing to me but then I’ve always been a fan of the Dinosaurs-Get-Nuked theory. And now there may be an equally solid case on favour of the Chixalub asteroid from a slightly different field of science.

Meet Pincelli Hull. Aside from having an awesome name, she has not quite got the same backstory as Keller, although her life has shown the same free spiritedness.

My name is Pincelli Hull. I’m a Biologist. And I’m here to kick ass

Her specific field is marine plankton fossils, and while she accepted the asteroid strike theory from when she first got into the field, she’d stayed clear of all the fighting.

That changed over time. First, a paleontologist friend who worked on other time periods argued that of course both the asteroid and volcanism were responsible. “I remember feeling so irritated,” Hull said. “This isn’t your topic of study; how do you have an opinion on this?”

Yeah! What is it with experts in one field who think they can poke their nose into other fields. You keep doing that and pretty soon you’ll have nuclear physicists pushing paleontologists around and statisticians bullying epidemiologists. 😉

…there were two papers that were published in 2019. They used two different geological chronometers to date the Deccan Traps,

And I realized that this is my moment. We can use my seafloor data to actually test these two hypotheses.

Fossils of Marine Plankton, roughly salt grain sized.

What she found with her data was that the plankton had gradually moved towards the poles of the earth over a period of about 200,000 years because the planet was warming up, almost certainly due to the Deccan Traps volcanic eruptions. But then they move back towards the equator because the planet was cooling. And then everything changed at once:

The boring story is that you’re looking at the late Cretaceous for millions of years. Climate goes up, it gets a little warmer, or colder, warmer, colder. But effectively, there’s nothing much to talk about. And then right at the impact, all the records go haywire.

They do show a slight warming and a slight cooling. But it’s nothing to write home about. The only thing that really jumps out at you is: Look at the impact. Everything in the deep sea goes crazy.

We’ll see what Ms. Keller does with this, since much of her evidence is based on another sea-based form of life: forum (technically Foraminifera):

Three hundred thousand years before Alvarez’s asteroid struck, some foram populations had already started to decline. Keller found that they had become less and less robust until, very rapidly, about a third of them vanished. “My takeaway was that you could not have a single instantaneous event causing this pattern,”

Forum fossils vs plankton fossils! Who will win? Much as admire Ms. Keller I think this is yet another nail in the coffin of her volcano theory.

Written by Tom Hunter

April 9, 2020 at 10:01 pm

Posted in Science, Space

Tagged with , , ,

Dinosaur Wars and The Nine Foot Problem.

At some stage in their lives, almost every kid loves dinosaurs. There’s just something cool about creatures that look like nothing seen in everyday life, that are big and scary, but which even a kid knows walk the Earth no longer.

There were many theories about the mysterious end of the dinosaurs 66 million years ago, which seemed to happen very quickly in the context of life on Earth,  though not suddenly it seemed. The theories ranged from serious, if mundane ones like volcanoes erupting around the planet causing climate change, to boutique notions about gluttony, food poisoning, and sexual impotence. All anybody knew for sure was that below a certain layer of dark, grey rock there were dinosaur fossils aplenty, and none at all above it.

This layer of fossilised ash and other burned material, no thicker than a notebook, was found all over the world and dated from 66 million years ago. It came to be called the KT boundary, because it marks the dividing line between the Cretaceous period and the Tertiary Period that we live in today. The name Cretaceous was derived from the Latin word Creta, meaning chalk, because that was the main rock found in early European studies of the geology. However, the letter “C” was already used so “K” was chosen instead, being the first letter of the German word for chalk: Kreide. The Tertiary period has been redefined as the Paleogene, but the term “KT” persists. Only scientists care!

For paleontologists it was just another layer of rock: nothing special aside from the slow and steady decline in dinosaur fossils leading up to it, the suspicious date and its global presence. There had been four other mass extinctions in Earth’s history, also with many theories as to their cause, and none of them had been sudden. There was also general distaste among scientists for catastrophe theories. They smacked of Noah’s Ark and The Great Flood. By the 1950’s evolution was taken to be a slow, steady process of change in which new species emerged and old species died out. Nobody was even raising the question about instant, mass, global, death.

So it came as rather a shock when, in 1980, an article was published in the magazine, Science, providing solid evidence that the dinosaurs had been wiped out by a giant asteroid hitting the Earth. What was worse was that this theory had been developed not by crusty paleontologists but a couple of chemists, a young geologist named Walter Alvarez, and his father, Luis Alvarez, a famous nuclear physicist, veteran of the Manhattan Project, and Nobel Prize Winner.

Their theory emerged from investigations of the KT boundary in the late 1970’s. What the Alvarez team found, starting with samples from Denmark and New Zealand, was that the layer was laced with the metal iridium, between 20 and 160 times the amount found in the rest of the Earth’s crust, where it’s rare. But there is one place where it’s common: asteroids. The Alvarez’s knew this, so they came to a quick conclusion.

All too quick for the dinosaur scientists. It rapidly gained traction in the scientific community but a massive brawl erupted that lasted through the decade, not helped by Alvarez senior’s standard nuclear physicist contempt for other “weak sister” scientific disciplines:

“I don’t like to say bad things about paleontologists, but they’re really not very good scientists. They’re more like stamp collectors.”

The theory also exploded in the media:

Science reporters cheered having a story that united dinosaurs and extraterrestrials and Cold War fever dreams—it needed only “some sex and the involvement of the Royal Family and the whole world would be paying attention,” one journalist wrote.

Still, the stamp collectors did have a couple of solid counter-factuals. First, where was the crater from this giant impact? Something that big would not have been wiped out by plate tectonics in only 66 million years.  Second, if it was instant, why were there no dinosaur fossils in the layer itself? In a century and a half of searching, almost no dinosaur remains had been found in the layers nine feet below the KT boundary, a depth representing hundreds of thousands of years. This became known as “the nine foot problem“.

The strongest alternative theory was the Deccan Traps. These were super volcanoes in India that spewed out an estimated 720,000 cubic miles of lava, covering an area three times the size of France, over hundreds of thousands of years up to the KT boundary and beyond. The outpouring would have drastically changed the Earth’s climate during this time, killing off a lot of species around the world, including the dinosaurs.

The theory also had a recent example, Iceland’s Laki volcano, which ripped open on June 8, 1783, in a so-called fissure eruption like the Deccan Traps and which rapidly spread environmental misery around the world:

Benjamin Franklin reported a “constant fog” over “a great part of North America.” Severe droughts plagued India, China, and Egypt. Cold temperatures in Japan ushered in what is remembered as the “year without a summer,” and the nation suffered the worst famine in its history. Throughout Europe, crops turned white and withered, and in June, desiccated leaves covered the ground as though it were October. 

This from an eruption thousands of times smaller than the ones in India. Adherents of the theory fought hard for it. None harder than Gerta Keller, a 73-year-old paleontology and geology professor at Princeton University, who still completely dismisses the asteroid idea:

“It’s like a fairy tale: ‘Big rock from sky hits the dinosaurs, and boom they go’. And it has all the aspects of a really nice story. It’s just not true.”

Keller herself is quite a character. Starting out from a very poor family of twelve kids on a Swiss farm (her pet dog served as “mutton” one day), she rejected being a nun, tried to commit suicide by sleeping pill, started work as a dressmaker for Christian Dior, then quit when she was 19 to hitchhike around the world. In those travels she escaped death three more times: from hepatitis contracted during an Algerian coup she got caught up in, getting shot and badly wounded by an escaping bank robber in Australia, and getting food poisoning in India. She ended up in San Francisco, started studying anthropology and ended up with a PhD in geology at Princeton, where she now has tenure.

Shades of Indiana Jones! Such a woman is not going to back down in the face of criticism:

Keller keeps a running list of insults that other scientists have hurled at her, either behind her back or to her face. She says she’s been called a “bitch” and “the most dangerous woman in the world,” who “should be stoned and burned at the stake.”

Various scientists told me, on the record, that they consider her “fringe,” “unethical,” “particularly dishonest,” and “a gadfly.” Keller, not to be outdone, called one impacter a “crybaby,” another a “bully,” and a third “the Trump of science.”

All of this and more is documented in a superb article in the September 2018 edition of The AtlanticThe Nastiest Feud in Science. Your view of our white-lab-coated comrades will never be the same:

“It’s like the Thirty Years’ War,” says Kirk Johnson, the director of the Smithsonian’s National Museum of Natural History. Impacters’ case-closed confidence belies decades of vicious infighting, with the two sides trading accusations of slander, sabotage, threats, discrimination, spurious data, and attempts to torpedo careers.

And you thought the Climate Change fight was ugly. But this is actually how science has often moved forward in history; supposedly an idealized process guided by objectivity, reason and the search for truth – it also has personalities, egos and politics fully in the mix. But the fighting also results from the simple fact that a lot of this stuff is truly hard to figure out:

Differing methods and standards of proof failed to translate across fields. Where the physicists trusted models, for example, geologists demanded observations from fieldwork. Yet even specialists from complementary disciplines like geology and paleontology butted heads over crucial interpretations

In 1997, hoping to reconcile disagreement over the speed of extinction, scientists organized a blind test in which they distributed fossil samples from the same site to six researchers. The researchers came back exactly split.

But there was no split on one fact that appeared in 1991. The discovery of the vast Chixalub crater in the Gulf of Mexico, buried under layers of sediment but clearly discernable using geologic survey techniques from the oil industry. Drilling into the rock revealed the crater was 66 million years old. It was like a DNA test result.

It explained almost everything, because now there was solid data. The crater is 111 miles in diameter and 18 miles deep, meaning an asteroid some 6 miles wide had hit the planet at 45,000mph, with the force of at least ten billion Hiroshima bombs. Had it been a deep ocean the results might not have been so bad. But the area had shallow waters and light sedimentary rock, so vast amounts of superheated material were thrown into space, most of which fell back on the planet to start forest fires,  and create suffocating darkness, along with giant tsunamis and magnitude 12 earthquakes. Clearly all that could spread destruction around the planet. It set the seal on the asteroid theory for most scientists, some of whom referred to it as the “bad weekend” scenario.

But that still left the nine foot problem and Keller’s argument for volcanoes:

When Keller examined the El Kef samples, she did not see a “bad weekend,” but a bad era: Three hundred thousand years before Alvarez’s asteroid struck, some foram populations had already started to decline. Keller found that they had become less and less robust until, very rapidly, about a third of them vanished. “My takeaway was that you could not have a single instantaneous event causing this pattern,”

However, this last bastion of the volcano defence may be about to fall, as described in a recent article, The Day The Dinosaurs Died.

For the last few years a graduate student, Robert DePalma, has been digging around in the Hell Creek geological formation, which has outcrops in parts of North and South Dakota, Montana, and Wyoming. It contains some of the greatest dinosaur fossil beds in the world and most of it is on private land. The first T-Rex was found there and the 19th century fossil searches caused huge fights between paleontologists:

They raided each other’s quarries, bribed each other’s crews, and vilified each other in print and at scientific meetings. In 1890, the New York Herald began a series of sensational articles about the controversy with the headline “SCIENTISTS WAGE BITTER WARFARE” 

Sounds familiar. In 2012 DePalma heard about an unusual site on a cattle ranch near Bowman, North Dakota. A private collector showed DePalma the site and told him that he was welcome to it because he thought it was a bust, with fossils so delicate they crumbled as soon as they met air.

At first DePalma was also not impressed. At an earlier site he’d been able to show each layer having being laid down by single rainstorms, a detailed history story, whereas this site seemed to be from a single flood. But when he poked around he saw potential:

The flood had entombed everything immediately, so specimens were exquisitely preserved. He found many complete fish, which are rare in the Hell Creek Formation,

Most fossils end up being squashed flat by the pressure of the overlying stone, but here everything was three-dimensional, including the fish, having been encased in sediment all at once.

And clearly this had been a very violent, sudden flood, with bodies ripped apart, logjams of wood, fish broken against trees, one fish impaled on another, tree trunks smeared with amber that meant they were alive when entombed.

When DePalma took out [a paddlefish] fossil, he found underneath it a tooth from a mosasaur, a giant carnivorous marine reptile. He wondered how a freshwater fish and a marine reptile could have ended up in the same place, on a riverbank at least several miles inland from the nearest sea.

The site has turned out to be one of the richest fossil finds in history. The writer notes that in most digs days or weeks can pass with little found, whereas DePalma was finding something noteworthy about every half hour.

DePalma identified the broken teeth and bones, including hatchling remains, of almost every dinosaur group known from Hell Creek, as well as pterosaur remains, which had previously been found only in layers far below the KT boundary. He found, intact, an unhatched egg containing an embryo—a fossil of immense research value. The egg and the other remains suggested that dinosaurs and major reptiles were probably not staggering into extinction…

But it was when he studied the layers of mud around the fossils – typically discarded as “overburden” because it’s material deposited much later and of little interest to paleontologists – that DePalma discovered a different type of “fossil”. He saw a preserved three inch crater formed by an object that had fallen from the sky into mud. Similar formations, from hailstones, have been found before in fossil records. But at the bottom of the crater he found not a hailstone but a small, white, 3mm-wide sphere.

It was a tektite, a blob of glass formed when molten rock is blasted into the air by an asteroid impact and falls back to Earth. He began to find many others like it. Earlier he’d found microtektites in the layers, but they could have been carried there by water. These had been trapped where they fell.

“When I saw that, I knew this wasn’t just any flood deposit,” DePalma said. “We weren’t just near the KT boundary—this whole site is the KT boundary!”

Then he began finding microtektites jammed into fossilised gills – sucked in by fish as they tried to breathe, and tektites in the amber of the trees. When these were compared to known Chixalub tektites from Haiti they were a near-perfect geo-chemical match.

There was one final problem with the theory. DePalma had assumed the flood was one of the giant tsunamis from the Chixalub hit 2000 miles away, until he realised that even at the speed they travel, they would have reached the site long after the rain of molten glass and rock ended. They would also have been too weak to account for the 35 foot water surge at the site. Once again this was not a problem for a palentologist but a geologist.

The answer arose from a strange event tied to the 2011 Japanese earthquake. Thirty minutes after that quake and 5000 miles away, an absolutely calm Norwegian fjord had produced bizarre, five-foot high waves: an earthquake phenomena called a seiche. The Chixalub earthquakes were a thousand times stronger. Different types of seismic waves travel at different speeds and would have hit the site six minutes, ten minutes, and thirteen minutes after the impact, triggering large seiches, while the first blobs of molten glass started to rain down. The waves would have rolled in and out for some time, trapping tektites each time during the hour they fell after the impact.

What this meant was that the site does not just record the day of impact, but the first hour or so, a degree of precision that seems unbelievable for a 66 million year old event. Much work remains to be done and even some impact experts remain hesitant to give this discovery its due. But it does seem to have solved the nine foot problem.

DePalma has named the site Tanis, a homage to the film, Raiders of The Lost Ark, where the city was the resting place of the Ark of the CovenantIt seems appropriate, but it will probably be just one more reason for Gerta Keller to hate it with every fibre of her being.

Written by Tom Hunter

June 2, 2019 at 7:32 am

Posted in Science, Space

Tagged with , , ,