First of all: What is science, but a story about what we think is how the universe works? It is just a story. It may have evidence to justify it, it may be logically connected and have causality and results that can be experimentally reproduced. But it is still, just a story.
You should understand that science isn’t a stately progression of learned gentlefolk considering evidence with reason and common sense, before deciding on TRUTH.
That is camouflage and public relations hype for what is, in reality, a slow-motion bar fight with opinionated eccentrics with monumental egos threatening each other’s lives, careers, and places in history, using spurious data, cockeyed theories, and personalities that their mothers couldn’t love.
As a side note, Gregor Mendel faked his data and threw out any outlying results that didn’t fit his theory of heredity.
So, one “scientist” will try to explain how they think something works, and then their esteemed colleagues will come back at them, challenging: “I’ll make you eat your words!” and attempt to prove They are wrong, and will prove it using methods, “logic,” and evidence they both agree on. Then, there is the pressure on people in academia to publish or perish. And sometimes the more controversial the paper purports to be, the better.
So, beneath the calm obscure language of scholarly papers in scientific journals there are deadly insults, blood-curdling threats, and enough disinformation to power a presidential election. Which brings us to the K-T Boundary Layer visible on the banks of the Brazos River near the 413 bridge over the Brazos, near Eloise, TX. It may not be as conclusive as we would like.
Eloise is a 4 corners (not really a town) about 2/3 of the way to Waco from Houston. The launch site is under the 413 bridge over the Brazos.
The outcrop that is visible on the bank of the Brazos is about a 100 yards downstream from the bridge.
We all kind of agree that dinosaurs existed sometime in the past, right? And except for their distant descendants, birds, they don’t exist any longer. Well, except for the folks who think the Earth is flat. I have an argument that proves it isn’t flat, though. If the world was flat, cats would have pushed everything off the edge by now.
So, some scientists have tried to explain what happened to kill all the dinosaurs off. And WHEN that happened.
The evidence that they existed is found in collections of giant fossilized bones that look exactly like chicken bones, except they have been turned to stone, and would be a chicken if the chicken were the size of a house.
Also, these bones are found in layers of rock and mud that most people agree must have been laid down millions and millions of years ago.
Geologists try to figure out how long ago something happened, by looking at the processes we see going on around us now, and seeing how they are laying down new layers of dirt or rocks, or disturbing and removing layers that were already there. Soil deposition, erosion, earthquakes, volcanoes, headlands erode, rivers carry soil to the sea, and meteorites deposit hundreds of tons of dust onto the Earth every year. The dust that comes across the ocean from Africa, for instance, happens regularly on an annual basis, and if you can find an undisturbed patch of ground and dig up a soil core, you could look for the residue of African dust, and count how many years it took to build up a certain amount of soil. It works just like counting tree rings. Some areas have processes that build up slowly, taking centuries to build up a couple of inches of layers. Some areas in Central America have mudslides that deposit a couple of feet of new soil in the valleys every year. Volcanoes have distinctive chemical makeup that can allow a geologist to trace particular layers of volcanic ash to specific volcanic eruptions with historic records.
And then, you have burrowing animals, earthquakes and floods and tsunamis that can mix things up. There is evidence that at least a billion years of layers that should be evident all around the world, are flat out missing from our geologic record.
Flat out “missing.”
They call it “The Great Unconformity.” It’s a mystery still. Geologists don’t really know what happened. Because it’s missing.
When geologists were studying the layers of sediment where dinosaur bones (and thousands of other fossils) were found, they discovered that, worldwide, there would be layers and layers that contained lots of different fossils, but then there was a layer that didn’t have any fossils. And usually, there were several layers above that that also didn’t have fossils. Something had obviously happened that killed off most animals and plants on Earth. For centuries. They called it the boundary between the Cretaceous geologic period and the Tertiary geologic period. Hence, we call it the K-T Boundary. Alas, while everybody knows what we mean when we refer to it, scientists have continued to refine how they think of the geologic ages, and neither the Cretaceous, nor the Tertiary geologic ages are accepted names any longer. The ages before the dinosaurs disappeared is called “The Mesozoic,” and the age after they disappeared is called “The Paleogene.” But we still call it the K-T boundary. Because everybody knows what we mean when we call it that.
Light colored K-T Boundary. Photo by Constantin Platon
While studying the layer immediately above the last layer with plentiful fossils, paleontologists discovered a couple of things. One: the layer immediately above the last layer with plentiful fossils often had charcoal or burned remains in it, and two: the layer had a substantial amount of Iridium in it. Iridium is a rare radioactive element, and is extremely rare anywhere else on Earth, EXCEPT in the thin layer of clay directly above the last layer with plentiful fossils.
Charcoal layer above the K-T boundary layer. Photo by Constantin Platon
Iridium is also plentiful in many meteorites.
While trying to tell the story of what may have happened to the dinosaurs, a team of physicists, geologists, and chemists concluded that a massive asteroid impact must have happened, that cooked the Earth worldwide to a temperature of several hundred degrees from the force of the impact and the resulting molten rock that splashed into the atmosphere for a week or so, and spread dust and debris from the asteroid, also throughout the world. Afterwards, the dust and sulfur dioxide that the impact threw into the atmosphere blocked sunlight, and caused Earth to turn into a cold ice ball for thousands of years. They told it as a story of: “The Asteroid that Killed the Dinosaurs.”
This was immediately refuted by other geologists, who pointed out that at about the same time, even thousands of years earlier, there was a massive, massive volcanic event in India, that spread hundreds of thousands of cubic miles of lava over a third of the subcontinent of India and lasted for up to a million years. The resulting flood of magma across India is called “The Deccan Traps.” “Traps” in this case, is derived from the Swedish word for “Stairs.” Which is what the lava flows look like in India today. The amount of dust, heat, and poisonous gases that would have spread over the entire world as a result of the enormous eruptions, would also account for the decimation of the dinosaurs. And didn’t need any hypothetical cosmic impact to kill off dinosaurs.
There has been spirited discussion of this for the past several years. But a couple of things have recently been noted: The dating of the two events are not exact. The volcanism in India might have started a couple of thousand years later, and the date of the asteroid impact might have been a couple of thousand years earlier. The margin of error for the two dates easily overlap, making it easily possible for the two events to have happened at the same time.
And also, it is really possible that the asteroid impact CAUSED the volcanic eruptions in India. Due to continental drift, 65 million years ago India was practically directly on the other side of Earth from the Chicxulub impact site, and the momentum of the impact could very well have transferred to the molten interior of Earth, and impelled the molten rock to spew out in India.
In support of that theory, it is well known that on the surface of Mars, the largest mountain there, Olympus Mons, is directly on the opposite side of Mars from the largest impact crater on Mars, Hellas Impact Crater. Since continental drift is not active on Mars, it is pretty well accepted that the asteroid that impacted Mars to make Hellas Crater, caused the volcanism that created Olympus Mons on the opposite side of the planet.
Many geologists are beginning to suspect that that is the case with the Chicxulub impact, and the volcanism that created the Deccan Traps.
That brings us back to the layer visible on the banks of the Brazos. That area of what is now Texas was underwater at the time. Under maybe a couple of dozen or couple of hundred feet of a shallow sea. You can find layers of fossils, and then a thin layer of clay, and then a black layer about a foot thick above it. But floods may have messed with it in the distant past. Modern animals have been burrowing into the different layers, and the record is not as distinct as we would like. There is a much greater abundance of Iridium in there somewhere, but not as clearly isolated in the thin clay layer. And then the evidence of worldwide volcanic ash and residues from India is mixed in with everything else.
But I think the preponderance of evidence is enough to satisfy me that the thin layer of clay indicates the visible K-T boundary, and the layer of black coal-like stuff above it indicates the residue from the cooked Earth that resulted for hundreds of years of ashes, followed by thousands of years of global freezing. We can gaze on those layers and know: We live on a dynamic planet, in a dynamic Universe. And those layers are from 65 million years ago, and represent an event, or series of events that killed off 75 percent of everything that lived on Earth. And we can see the evidence for it on the banks of the Brazos.
That’s my story, and I’m sticking to it.
References:
M Hart, et al., The Cretaceous-Paleogene boundary on the Brazos River, Texas: New stratigraphic sections and revised interpretations. GCAGS J 1, 69–80 (2013).
WS Wolbach, I Gilmour, E Anders, Major wildfires at the Cretaceous/Tertiary boundary. Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality, eds VL Sharpton, PD Ward (Geological Society of America, Boulder, CO) Vol 247, 247–391 (1990).
N Artemieva, et al., Quantifying the release of climate-active gases by large meteorite impacts with a case study of Chicxulub. Geophys Res Lett 44, 10180–10188 (2017).
A Hildebrand, et al., Chicxulub crater: A possible Cretaceous/Tertiary boundary impact crater on the Yucatán Peninsula, Mexico. Geology 19, 867–871 (1991).
LW Alvarez, W Alvarez, F Asaro, HV Michel, Extraterrestrial cause for the cretaceous-tertiary extinction. Science 208, 1095–1108 (1980).
Deccan Volcanism caused the mass extinction 66 Million Years Ago, Gerta Keller, Professor of Geosciences, Princeton University. 9-23-2020.