No Minister

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 , , ,

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