This is geology B with Oliver stream people.
The hypothesis that the mass extinction at the end of the
Cretaceous was caused by the impact of a large.
Asteroid was first proposed by Louis and Walter Alvarez and
independently by Ian, Schmitt in 1980, the impact hypothesis is,
now widely accepted by the scientific Community, but many
details as to how this one-of-a-kind event affected the
Earth and living things, remain unclear.
Then in 2019, the announcement of a new find in North Dakota
created its own Big Splash and astonishingly detailed snapshot
of the immediate aftermath of the impact event had been found.
Jan Smit is Emeritus, professor of event stratigraphy at the
Free University of Amsterdam. Initially a paleontologist
studying planktonic, foraminifera.
He became intrigued by what appeared to be very sudden
events. In the fossil record and
increasingly Focus his research on the boundary between the
Cretaceous and the paleogene, the so-called KT boundary.
He is one of the lead authors on the paper announcing the North
Dakota discovery. Jan Smit.
Welcome to geology, B. Thank you.
You were one of the first to suggest the impact hypothesis
for the end, Cretaceous mass extinction that destroyed the
non-avian dinosaurs, as well as a myriad of other terrestrial
and marine organisms. What were the competing
hypotheses at the time? I think somebody tabulated a
number of 50 of either sensible or non sensible explanations for
The Disappearance. But most of them started from
something which is Earthbound like climate changes.
It could have been colder. It could it be wetter?
It could have been warmer. The Seas might have changed.
A lot of theories concerned about the opening and closing of
gateways in the sea and like the separation.
Between South and North America. And a lot of people thought,
okay, there was a Gateway open and somehow the ocean currents
ran through between North and South America.
And they started to create Hayfork among organisms.
Of course, volcanism was suggested that if you put
enough, toxic gases in the atmosphere or CO2 or SO2 or
something like that, we know, big volcanic, eruptions can have
consequences. And then there was, and there
was the time I met Walter Alvarez in 1979 in the
conference, There Was an explanation, which was even more
ingenious. They thought that during plate
tectonics, the Arctic sea right now it's a North Atlantic is
open to the Arctic seas, but at that time, the gap between
Norway and Greenland was closed and so was probably the Bering
Strait. So the idea was that there is a
huge ocean. Right at the spot where the
North Pole is according to them. It was probably freshwater body
a comparable to giant-sized, Great Lakes like in North
America. The opening of the North
Atlantic was probably happening around the cretaceous-tertiary
boundary. So the idea was that fresh
water, which even if it's colder is still lighter than normal,
ocean water was spilling out over the northern Atlantic and
eventually over the entire Roshan probably was shutting
down the circulation between the deep ocean and the shallow
Waters. Well, that's an elegant idea, of
course, because that way, you can kill off the Plankton which
are for the most of them are tropical or subtropical species.
So it happened in a fairly short time.
And, of course, the dinosaurs were killed by the Arctic
flooding as they called it, because it would cool the
climate and since dinosaurs are reptiles the thinking was that
they couldn't. You're 52, cold spell, following
the spillage of the Arctic Ocean over the entire ocean.
So these were the sort of theories floating around at that
time. So then you and the averages
came up with the asteroid impact hypothesis.
Before the recent discovery in North Dakota.
What did we infer about the nature of this impact?
And what was the evidence based on all of course the first
evidence This was the finding of the Platinum Group elements
iridium is the foremost of them among those Platinum Group.
They are all what we call iron loving sodaro files, so iron and
nickel and chromium, and Cobalt are enriched as well.
And the ratio between the Platinum Group elements was very
close to what we call a chondritic asteroid body.
So that was the first indication that the Iridium although there
were theories that it could be Spilled Out of a volcano and the
deep-seeded 4K know maybe in hot spots volcano that even that
iridium would deviate from the what we call the chondritic
ratio. And before I found the Iridium,
I was looking at the tiny layer which separated the Cretaceous
and the tertiary. In the meantime, I started
looking at many places like Denmark, Italy, Germany, France,
north of Spain. Wherever I looked there was a
clay layer which consisted of two parts.
The lower part is a very thin layer about 23.
Mm, and it doesn't matter where you look in the Pacific Ocean
and New Zealand Europe or in the Atlantic.
It's more or less 2 to 3. Hours.
And it's also the most enriched in Platinum Group elements and
iridium. The second layer is much
thicker, and that layer is created by the supply of clay
from land, and windblown and rivers, Etc.
Because if you kill off the planktonic organisms, which bear
a calcareous skeleton, they don't sink to the sea floor and
make a limestone layer. Now, what you get is a layer of
clay, from the windblown dust and the Dust.
Then the clay derived from Reverend sources.
So that was the second indication that we have a
two-fold layer and within that lower layer 2.
Mm, I found earlier a whole Suite of spherules Tiny's
Farrell's about half a millimeter.
We're the largest, they turned out to be crystalling.
I already suspected that they were the remains of what we call
Micro tektites and micro tektites are the product of a
big meteorite impact where the melted Stuff is squeezed,
underneath, the penetrating, meteorite and thrown out over a
large area of the globe. So, not only did we find the
Iridium, we know it had to produce these micro Tech tides
and that excluded, we simply have an accretion of
extraterrestrial matter how you can imagine that.
Instead of a big meteorite, we have an enormous amount of
smaller, meteorites landing on the surface of the Earth, but
these ferals have proven that. It must have hit some And the
world. We didn't know where and it kept
on going. So people found this strange
Isotopes and Bruce bow whore. A few years later found in the
same 2. Mm, thick layer, he found what
we call the shock cords, at tiny grains of quartz which under a
microscope show signs of a severe Sound Shock.
Like a plane going through, the sound barrier and they're highly
diagnostic for shock pressure. Hours which can only be created
by nuclear explosions or by meteorite impacts.
So one by one, the evidence in the early 80s was accumulating
that we had to deal with a very big impact.
So how did the discovery of the so-called Tanis site in North
Dakota? Come about the tennis side?
First came to my attention because Robert De Palma.
He just send me an email. And he said that he found
evidence for tsunami deposit in North Dakota.
Well, at first, I forgot about it because I had so many
mentions of so called tsunami deposits, but then he showed me
a couple of pictures and one of them is very important.
He showed me a piece of rock, he collected a very big piece with
three phases in it. A sturgeon in the pedal face
together with an ammonite. Now on ammonites is a purely
marine, sea animal, the squid-like organism.
But the sturgeon and especially the paddlefish are strictly
freshwater, and both of them are beautifully preserved, all the
details of the fin tips, Etc. So they had to be washed
together by some event, and also be very perfectly preserved, so
that convinced me that there was something very unusual there.
Why were you so skeptical, though?
Initially that there was another tsunami deposit there, well,
it's far away from the Gulf and it's very hard to imagine a
Jody. Schwa sort of calculated the
hate of the tsunami. She came up with a couple of
hundred meters, but even being a couple of hundred meters, it
will just diminish and disappear within a few hundred kilometers
and you still have to travel 2,000 km all the way up to
tennis. So I was quite skeptical, but
because he showed me the ammonite in the fish and he also
showed me the structure of the deposit, which is very similar
to what we discovered around the Gulf of Mexico.
I became more and more Vince and then he sent me pictures of the
tektites he found inside the deposit so I offered him.
Yeah. Okay.
We can date those tektites in our lab here in Amsterdam and
that's what we did. And it turned out to be exactly
the same age as the tektites in Haiti.
So I was convinced and I had to get there.
So at this point, you are convinced that it was part of
the same event somehow that had been well, documented around the
Gulf of Mexico and so on. So what happened when you
visited the Site and took a closer look, we had a
conversation between Robert and me, and when we were there, he
showed me all the carcasses and the whole deposit was sloping on
the River Band. It had all the typical Hallmarks
for me as a sedimentology stall. So that this was a high-energy
deposit with 12 pulses and in the top one are perfectly
preserved, fishes. And then he started scratching
the Earth from a big fish. A pedal face lying upside down.
And he said to me, look here, here's the upper and the lower
jaw and he started to dig between the both sides of the
lower jaw and before my eyes he pried out the gills of the fish
and in the gills and more importantly, the raker said
there was a sort of catch foot catch stuff where a lot of those
tektites. So this fish must have been
swallowing tektites while he was still alive.
So whether he died from the event or not, he had to die very
close within hours or something of the impact itself.
Let me see if I get the logic. So because you found the
tektites in the gills of these filter-feeding paddlefish.
How does that tell you, they died within an hour or two of
the impact, a couple of things because they're very effective
in swallowing their food stuff. So whatever he catches while
swimming, He does it as a pelagic face.
Open, mouth, he swims in the river.
Sea must have caught them when they were still raining out of
the sky. It's not the bottom feeder, like
a sturgeon. And so, he caught him in the
gills and they didn't get any farther than that.
We have x-ray. Scans in high detail in 3D and
you can see that the gut, the beginning of the gut of those
fishes is also preserved, but none of it contains any
tektites. So I'm not a specialist in
fishes, but I could imagine That he swallows, whatever he catches
within minutes and ingested in his intestine.
So we didn't see that. So in other words, there was
time for it to get caught in the gills, but no time before it
died for it to get from the gills into the digestive system.
So I think he has mechanisms to remove those objects from his
guilt but just swimming harder or, or swimming in the reverse
or whatever, but they still in there as 60% of the fishes we
That they're half the tektite still inside their gills and
combined with the perfect preservation at the body's not
being swollen and also because above the Tomb of the fishes are
additional tektites. So while they are dying
additional tektites come from the sky land on succeeding layer
of Toonami deposits, while the fishes are already buried.
So, that's the time window, you have it still within the reign
of tectonic. Tides coming from chicks Loop.
Well, and that's a very narrow window of the first ones arrive
in say, in 15 minutes and the latest come within an hour or
so, and maybe some hours, but that's really stretching it.
But that's a very narrow window of where they have to die.
So I would submit that they are the direct victims of the
chicks. Look itself.
There's probably no other way to explain it, okay?
So both the distribution of the tektites inside the fish but
also the distribution around the fish in that deposit.
With a tektite show that this whole event had to have happened
at most within about two hours or something.
Exactly. Yeah.
And so now we're 3,000 kilometers away from the impact
so that's just just doesn't compute for the travel time of
its tsunami. So how did you resolve this
conundrum? I happen to travel around around
the same time in India. Looking for the effects of the
Deccan traps just by way of background the justice.
The Deccan traps are a very extensive 2 km thick sequence of
lava flows in central. India that erupted in the space
of a few tens of thousands of years, more or less.
Coincident with the end of the Cretaceous, the volcanic gases
released during the formation of the traps have been thought to
be implicated in the end. Cretaceous Extinction event both
via the sudden, cooling of the climate.
They may have induced as well as through the toxicity of the gas.
Is I think you told me you were traveling there with a
geophysicist friend called Mark Richards.
Yeah. And he just conceived a theory
that Deccan traps. Might have been erupted more
severely as a consequence of the impact.
The impact didn't start the Deccan traps with the
accelerated and so I told them the whole story because I've
been there just in the fall and in the winter, we were in India.
So a couple of months apart, we're still thinking and he
said, John, there's no way you can get Get your tsunamis in
time there. And secondly, he said, I may
have a solution for you, and then he showed me a picture of a
few short in Norway, where people filmed at tsunami in the
Sonia flirt and another Fjord, which originated about half an
hour after the giant earthquake in Japan in 2011, and what you
see is really amazing, one and a half meters sized tsunamis
running up shore in a fjord in Norway.
A thousand kilometers away from that severe earthquake 9 from
Japan. So there is a way he said to
trigger a body of water, probably by putting it in
resonance with the earthquake waves, which are arriving there.
And he said, since the earthquake caused by chicks,
Loop is about 50 times or two orders of magnitude more
powerful at that's the minimum estimate, then the largest
earthquake which can be caused by plate tectonics.
And which is a 9.6 in Chile and he believes it's an 11 point, 6
or 7 is the maximum by the impact, the waves and the
amplitude of the waves, at that distance, 34 thousand kilometers
away from the impact. Could have triggered, our could
have pulled the body of water in a resonant mode and cost in situ
here in North Dakota itself. If there is a shallow sea there
and run up the tennis River within the required amount
between, half an hour and a couple of hours, how thick is a
surge deposit and can you talk a little bit about the different
layers in it and the tactics and how much detail that provides us
but what actually would have happened then in the essentially
first First hour or two, after this impact.
What we clearly see in the field is that the first search is the
most energetic. Because at the bottom of the
river Channel, we find Boulders about half a meter in size but
they quickly become thinner. And then we get a sense down
body with all the indication of an enormous sediment load, which
grades up words within half a meter in meter into the deposits
where the fishes are were burnt, logs, are where The other
trophies are of riparian fauna and Flora which is existing at
the time in the topmost Cretaceous.
So, apparently the search running a braver was powerful
enough to rip branches to kill animals to kill the fishes for
instance and it's not only the big ones are smaller fishes.
We see shark teeth. There are insects that are wasps
surprised by the water there and nests are memo Burroughs.
They're all so they provide the sort of snapshot of living
things in the area, which besides are perfectly buried in
the Tomb Stone of tennis. So it offers us besides being an
intriguing deposits related to the impact, a glimpse of what
life was in the close of the Cretaceous.
Does, it also explain how the ammonites are the marine species
got into this freshwater environment?
Yeah, that's still a problem for the model as though, but they're
perfectly preserved, their nice shells.
We have no Evidence that the fish were clearly alive.
When they were buried, we have no life ammonites.
So it could have been lucky today.
You find on the beaches of Indonesia.
You find those nice mother of pearl shells of nautiloids.
So the shells could have been lying on the beach and then
being swept up. But you still need a shoreline
on a marine Coast where the salt water moves inward are thinking
is the fishes were not killed by the tektites because you had to
deal with certain search or saltwater.
Which it didn't like at all. So you have this picture of
something like a giant tidal bore sweeping up the shallow
River from the sea bringing with it ammonites and then creating a
huge run up on the bank and basically just washing all the
life out of the water. Now what exactly would have been
the cause of death under this situation?
Yeah you can think in a variety of things but what we also find
is evidence since there are three trunks about 5 meters in
length, is the largest ones and the surface of the tree trunks
are scorched that there is a thin layer of charcoal around
the tree trunks and on the tree trunks are pieces of Amber with
tektites inside the Amber. And the only way you can make
Amber sticky enough and liquid enough to be able to catch the
tektites while they were flying in, is by making it very soft by
a fire or something like that. And one of the initial kill
mechanisms, those zillions and billions of returning Ferrell's.
They must have created as many shooting stars at the same time,
which have called the sort of Broiler effects that you see the
incoming tektites at the height of 20, 40 kilometers.
And they created a blanket of strongly radiating stuff, which
must have Zapped. At least the surface of the
Earth just before the tsunami came up.
Up. So, it perfectly possible.
That a lot of the victims were created just before the tsunami.
So they were sort of suffocated at that time.
And then they were swept up by the tsunami.
So if they were cooked in the first hour or two, perhaps then
you had climate change and then they could freeze, I guess what
happened then. Yeah.
Do to Dear thrown up dust and it's a global layer of dust in
the stratosphere and edit with That is the very rare
circumstances that the meteorite in Yucatan, hit the layer of
gypsum. Which of course is highly rich
in Sulfur. The sulfur is also vaporized, so
including the dust and the sulfur, which is a sort of
whitish power and that's very capable of bouncing off and
reflecting sunlight back into space.
So the second effect after the first half hour of zapping, the
plants in charcoal in them is a freezing spell.
And there is still a scientific debate going on, is to freezing
spell lasting for a couple of months.
The, we stretched it to a maximum of 10 years, that
probably may be overdoing it. And there is other evidence for
it, migration patterns of dinoflagellates, which are
planktonic species, that did not expire.
And there is evidence in the way of the chemical composition of
the cell walls of certain bacteria, which are found in
situ in the layers and Texas and the quality of the membranes,
the Of cyclic components is a measurement of the ambient
temperature where they lived in, so that's supporting evidence
for the cold spell. And then if that range out, we
get all the greenhouse gases like methane CO2 and Cetera,
staying back in the atmosphere. So the third phase is a phase of
warm climate. It's not that warm.
I mean, it's not that warm as the first Bell, but it certainly
makes the atmosphere 10 degrees Centigrade warmer.
For a couple of thousand years. And that is how we explain the
survival of the species. That did survive, I guess the
birds, and maybe some detritus feeders in the water.
Exactly. Yeah.
They detritus feeders have a feast because they're not
dependent on the primary food source and one of the main kill
mechanisms proposed and I still think it's very valid is the
cessation of photosynthesis for a couple of months at besides
the cold spell. There is also that I mean,
sunlight is being effectively blocked.
So the whole food chain going from Tiny LJ dependent on
photosynthesis goes through the food chain letter.
And that's exactly what we see that.
The big species are dependent on smaller species and they feed on
algae and that's exactly what the interruption of the food
chain is. I just can't help being struck
by how amazing it is. That after a period of about 66
million years ago, you have a very thick layer about two and a
half meters. That was deposited all within
the space of about an hour. So you've got enormous temporal
resolution of of minutes literally 66 million years ago.
Yeah, that's amazing. But I thought unique we have now
in the deep sea and in the past Avalanches from the front of
Delta X which come down as an avalanche on the deep sea floor
and those can be sensed own bodies of meters in thickness.
Deposited in the same time frame, a couple of hours at most
So, yes, we're lucky. But these sort of event deposits
are created in a very short amount of time, while the
remaining sediments above and below the word very, very
slowly. So, if this seismic wave induced
River surge at Tanis happened in that location, do we think this
must have happened? Elsewhere along this River and
perhaps along other rivers. All over the continent.
In other words, can we expect to find many more?
Such sites. I think so too, but it may
require the geometry of the water body is just like the
Japan earthquake and some few words it did not.
And then other fjords it did create it tsunami.
So the morphology and the orientation of the seawater boar
is very important so it can be that a just happened in one
place because there is a funneling effect of the Estuary.
There is just the fortuitous lucky circumstances that tennis
was lucky but Along the Tennessee River, we might expect
to have more deposits like that definitely but so far we just
have this one. Soul Spot.
There have been at least five major extinctions during the
history of the Earth with perhaps the one at the end of
the Permian about 252 million years ago.
Being the largest one is that any evidence linking a possible
asteroid impact to any of these other extinctions?
Well of course people have looked in that respect the end
devonian Extinction which is one of the big five extinctions.
What's due to a Major Impact, making the sea non-transparent,
all the late devonian reefs. Which we know from Australia to
the Canadian Rockies, to Europe are killed at exactly the same
time. The only way you can do it is
also by preventing sunlight by making the waters turbot so the
sunlight can reach all the corals and they get extinct.
Okay, that was a nice idea. But of course many people have
looked in a good place in New York.
Okay, Upstate New York, no already in there, we have looked
at the permian-triassic, boundary in the Italian
dolomites, there's a very nice clay layer, which separates
shallow water, lime stones from the Permian to even shallower or
slightly deeper limestone's from the Triassic.
There is a nice clay layer there a couple of decimeter thick but
there's no, iridium. There night as ferals are
shocked quartz or something like that.
So that kind of whatever way it's disappointing.
We have not been able to find definitive evidence for any
contribution of a meteorite impact.
Except at the cretaceous-tertiary boundary are
you can say yeah if you want to find a common denominator for
all the extinctions had that people have looking for that and
that come back again, towards Falcon isms as the culprit.
So what are you working on at the moment?
I hope to write a book about KT, boundary my personal view on
that and see how everything interrelates, whatever
resistance was. Of course, there was lots of
criticism that makes it a very Lively debate.
People think that was gradual, how do you say?
It's gradual. And they made a mistake or I
made a mistake. So that's a lively debate and
still is going on the Vulcan estar clearly convinced that the
deck entrapped ended it all. And they see their evidence in
the light of the deck and she said, no, you have the wrong
view. We see Sitting in the light of
four major impact. Ian Smith, thank you very much.
It was a pleasure for more about geology, b, as well as pictures
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