Hello and welcome to NASA's Goddard Space Flight Center.
My name is Michelle Thaler, and we have a wonderful honor
today of presenting a scientific colloquium
about some amazing new results
having to do with the end of the dinosaurs.
This is something where space science
and earth science come together
and shows you how very much enmeshed
all of these different types of study are.
So we're honored today
to have Robert DePalma talking to us,
and he'll be giving this colloquium.
Now, Robert,
it turns out, is a doctoral
candidate will be very soon getting a doctorate,
I hope, in there for the University of Manchester.
Is that is that correct, Robert?
Yes. Michele, thank you so much.
It's an honor to be here today.
I will be getting a doctorate very soon
from University of Manchester.
And I'm on the faculty at University
at Florida Atlantic University.
And you introduce yourself
to me as a vertebrate paleontologist.
And you
and you specialize in the end of the Cretaceous period,
which was ended very suddenly by an event
we're going to talk about today. Absolutely right.
Okay. Well, enjoy the symposium. We'll be back later.
Thank you.
Thank you very much.
And today,
I'll be talking about a very, very exciting bit of research
that deals with probably one of the worst days of the Mesozoic.
It's when the Cretaceous ended.
And anything that would have experienced
that day would have
had probably the worst day that it ever, ever experienced.
That is, of course, the Teacher of Impact event.
And that event is what set in motion
a series of events that really changed
the topography of life on Earth as we know it.
And it set the stage for what we have today.
The important thing to remember, though,
is that the teaching of events and understanding the teaching
of event in every detail possible is literally our window
into the past.
To understand how Biota is going to respond to impact events,
how biota is going to respond to global scale hazards
, and in turn, how can we possibly deal with that today?
So it directly relates to what's going on today,
and that's where Earth and space science really meet.
And a little bit about the future of impact.
We're talking about an asteroid that was relatively
ten kilometers in diameter
and that's going to come in roughly 20 kilometers a second.
It's going to lose enormous amounts of energy.
You're going to have seismicity,
possibly magnitude 11 to a magnitude 12
at the impact site,
and that's greater than you're going to see
in the Earth normally.
And what that did is that set in motion
a cascade effect of ecological collapse.
You're going to block out the sun.
You're going to have
this injection of a massive amount
of contamination into the atmosphere.
And it's really going to set everything off kilter.
That is what set in motion the massive extinction
that basically took out 75% of species on earth.
So all of that that we know, we've got this tremendous
amount of information about the big event
and there's still questions that are unanswered.
We know all sorts of things about what happened
on these long timescales, talking in generalities.
So what happened over millions of years?
You know,
what's our percentage of species that died and what happened
on a large scale?
But what about those finer time scales?
What happened in the hour today?
Time scales.
And the fact of the matter is,
we just don't know the answers to a lot of those questions,
because the way to answer them depends on a geologic record
that is suited to answering those questions.
Most of your rock units don't preserve that sort of data.
And it takes a really special sort of a
an area special sort of a site to preserve
that kind of a snapshot.
And that's where this new site comes in.
So there's actually a new site
at the very end of the Cretaceous in North America
that preserves a snapshot of life on Earth.
And this site, it gives a very, very tight
view of what happened in the terrestrial setting.
It gives a view of what happened moments after impact.
We're able to see what happened
with the very first stages of ejecta accretion.
And we're basically able to see, well, what did happen in
that little tiny nugget of time
that really is sort of missing in the geologic record now.
How can we actually feel that
the site actually does that for us?
The study region is within the Hell Creek formation.
So that represents
roughly the last 1.3 million years of the Cretaceous.
It's a terrestrial setting,
sort of like the Gulf Coastal Plains today.
You had all these rivers that would have flowed
from the inland areas all the way out to the Seaway
that would have split the US in two.
Back then you had all these fluvial deposits.
You had lots of dinosaurs.
Life was abundant.
This was a vibrant, thriving ecosystem in the Hell Creek,
and it's a hotbed for Cape Research because it just happens
that this area is the best terrestrial succession
of Cretaceous to Paleocene rocks in the world.
And we're able to study the impact event most places
that is just preserved as a single layer of fallout.
But the new site actually
has something a little bit different in store.
Normally we see the cape do boundary, something like this.
There I am up on the the outcrop, studying the
dividing line between the Cretaceous and Paleo gene.
There's a closer view.
There's Professor Phil Manning and I digging into it.
And you can see that that layer is very, very distinct.
You've got your dark gray sediments
and this beautiful light colored,
this peach colored clay layer.
And that clay layer is 100% composed of impact
derived materials.
You've got shocked quartz, you've got ejecta, spherules,
you've got an iridium spike, you've got all this stuff
that was blasted into the air
and it came down around the entire globe
as this little layer.
And this is how it manifests in the Hell Creek formation.
We've heard about the impact event,
we've heard about the future of impact,
and we know the name Walter Alvarez.
It's associated with it.
And here we are actually digging into the layer at the site
and working through these these problems at this new site .
And it's sort of an incredible story
as it comes together with all the mines that are involved
and and piecing these little details together.
So let's get into the the site itself.
The site is known as Tanis.
And this site, the depositional setting,
is basically in a little river environment
back in the Cretaceous.
So you have point bars in the bends in the river.
And essentially what occurred is a massive surge of water left
a layer of mud as a drape over one of these point bars.
And you've got maybe ten and a half meters of elevation change.
So it's a pretty steep point bar.
And you've got this veneer of sediment
that got deposited really rapidly on the point bar.
It's actually really good for preservation.
And you can see here, it was a really turbulent deposit.
You've got all these
these chaotically deposited laminae of silt and sand
and mixed in with that,
you've got this mass death layer of mostly fish
and you've got trees, you've got other plants,
you've got other organisms all mixed in
to this really dense layer of dead creatures.
And this was all pushed in at relatively the same time.
And you can see it, right,
the chaotically oriented mud class at the bottom.
So what those are we call a rip up class.
And we have a really turbulent surge of water.
It's going to rip up whatever sediment it encounters.
It's going to trap basically. Right.
All those together,
it's going to tumble those and cause
this little layer of rip up class.
And that's what we see there.
We have our
sturgeon there and that's mostly what we see with the fish.
We have our sturgeon and paddlefish
and then mixed in with those,
we've got other terrestrial biota.
This is what the site looks like today.
It looks very, very different.
You don't have that subtropical area that we even
had the Hell Creek formation.
This is the Prairie and the the American West.
And you can actually kind of get an idea of the elevation
change there at the site.
We're about two thirds up that angled point bar.
And you can see way down there
at the vehicles is near the base of the point bar
and it even goes up from there .
We've got ten and a half meters of elevation change
continuously unbroken in that deposit.
And when we start digging up these
these remains, you can think, well, well, when are we?
You know, we're basically digging through time.
So when are we?
That's the big question we always ask.
And we have to answer that multiple different ways,
not just one.
And one of those ways is with the plants.
So the mega floor at the site
and this is one of the things
that has been independently verified by Baylor botanist
Patrick Herren.
DEAN And when we look at the flora that are present
in that that point bar deposit and the surge deposit
and compare that to the underlying sediments
that that river dug through,
the incised sediments which are obviously older,
we see a distinct difference in the flora between those
the flora there in the surge deposit
and that are in the point bar
are much younger and they constrain to the very,
very upper most Cretaceous, the terminal Cretaceous
and the uppermost hell creek formation.
Same with the pollen.
And this has been independently verified by paleontologist
Steve Bosworth.
And the pollen shows us the same thing pretty much that the
the flora show us basically the foot,
the pollen in the uppermost part of the deposit
and your point bar and in your surge deposit match
with the uppermost held creek, the terminal Cretaceous
and then the incised bedrock is a little bit older.
It's what you would expect.
So we've got these redundant ways
of basically putting a time stamp on our deposit.
And the ejected does that as well.
And here are some examples of the ejector here.
We've got this, the space component of this site, and
this is a basic stratigraphic column of the site.
And you can see the the grain size curve.
So you go from large to small green.
We've got two major pulses in the site.
They've got one major pulse
backflow and then another pulse that goes all the way up.
There's ejecta throughout this deposit.
You've got ejecta spherules like you see here
that would have come from the impact site.
You've got that impactor, it hits your target rock
and you get blobs of molten glass
and different material that shoot up into the sky,
out of the atmosphere and they come back down again.
And that is a diagnostic feature of impact, as
is your shocked quartz at right, which we find in the capping
jpg torn stein which caps the site.
So you literally have this ejecta bearing deposit,
which is capped by the very fine grained debris
from that impact event.
So that really seals it all together.
You also have micro Chris Stites.
So these are
formed as a condensate from the vaporized impactor.
So you've got that asteroid. It vaporizes on impact.
And as that condenses,
you get these forming
and you've got the
typical enrichments in chromium and nickel
and iron and so forth
that are attributed to the micro Chris sites.
Now getting into all the stuff that's buried in the deposit.
Let's get to the
coolest thing of all time, which is logs, right?
Because we all think logs are really cool, right?
Well, these logs actually happen to be cool
because in this site wrapped around the logs,
you've got all these animals and different things.
But the logs themselves,
which in some cases can be 20 to 30 feet long,
the longest ones we've dug up so far,
really well-preserved semi three dimensional,
but they also have runnels of amber on them.
So we know that resin would go down the trees
and we've got runnels of amber on the exterior of the logs .
Okay, that's great. We've all seen Jurassic Park.
We know that Amber is a great thing for paleontology.
But in this case, Amber,
when that resin is still flowing, is a way to capture
whatever is going through the air.
And on the day of the chuchu of impact,
that's the time when I really want to see what's in the amber.
So what are we finding here?
Well, we're sieving out the amber.
We're actually going through it.
There's Pym Cask is another researcher
who is doing work out there from Vue, Amsterdam.
And here are some of the pieces of amber from the site.
There's little pieces of the wood,
but here we've got pieces of amber from the site.
You can actually see
texture from the surface of that one
that that matches the bark from the tree.
So this is really well preserved.
Amber And when we look inside, we've got beautifully preserved.
Ejecta Spherules from the impact event.
These haven't been exposed yet.
They're still in the amber
and these two spherules have been exposed.
And we can see that
beautiful black glass of of the impact spiral.
That's not usually what you see what the future of impact
normally we're looking at what you see at left
a really awful crumbly clay spheroidal
because a really bad thing happens in the geologic record.
What happens is glass will then alter when it takes on water
so it hydrates and glass will then turn to clay.
In this case smectite clay
and it becomes crumbly and not too nice.
And we look at these as researchers of the
of the impact event and we think, oh, man,
what did that look like on the day of impact?
What did it look like when it was pristine?
And we have to
use our imaginations to think, what did that used to look like?
That's what it used to look like.
That's one of the only pristine
pieces of impact ejecta from the chuchu impact
and the amber there is full of it.
So that's a really good hotbed for research
and it helps us to give a fingerprint to the site.
Right.
So some of those little clay spirals didn't completely alter.
So this is a beautiful micro
CD that my colleague Lauren Gursky put together.
And the blue portion is the clay.
All right.
And the interior, the green portion
is the unaltered core of that sphere.
And looking at those and the ones from Amber,
we're able to establish a geochemical fingerprint
with the chuchu of impact
and with glass from the tree to the impact from elsewhere and
geochemical fingerprints on the crater site.
And also that glass has a temporal fingerprint.
So we're able to radiometric
date that argon argon dating
and come up with a date
that matches the CHUCHU lab event.
So able to match this of this event with the site,
with the biota, with the microorganisms,
with the geochemistry, with the radio isotopes, everything.
So we're able to come up with these reinforcing ways
of linking it with the chuchu live event.
So good.
We've got something that's linked to the day of the impact.
That's excellent.
So how can we get this timing
constrained a little bit in the ejecta sort of is our key
because that entire column of sediment.
Was getting deposited during active ejecta accretion.
Of course grained ejecta.
So basically since that site is covered
in your fine grained on stone.
That came out later.
And your column is filled with your coarse grain ejecta.
You're tied to that coarse, grain, dejected accretion
time window.
And that's within roughly the first hour,
maybe two at most after impact.
You want to be really, really generous, maybe, say an hour
and a half to 2 hours after impact.
And geologically speaking, that is the blink of an eye.
That is the sort of honey spot that we're looking for.
Because when you're looking at the impact event
in the terms of hundreds of thousands
to millions of years,
and you're able to get a site
with that sort of temporal resolution,
then you can answer all sorts of questions
if you find the right types of material there .
And that we know we're in the gold now.
Now is when we can start answering those questions.
Now, go back to the temporal resolution.
How can we possibly constrain that a little more?
The ejecta is our key.
We know that whole deposit was within the first hour
or two after impact,
but when we have lenses like that throughout the deposit,
we can work out based on their average diameter
when they would have arrived at the site.
And Walter
actually helped by doing a lot of those calculations.
And what we turned up was, is
you can get those different
lenses throughout the thing and those are basically
your little time stamps throughout the deposit.
You could further subdivide the chronology of this deposit
based on the incoming time of the ejecta spherules
and that's the beauty of the site.
So you can actually get this little
this little tidbit of a view every step up the column.
But that doesn't
actually solve the surge where the surge come from.
I'm not going to belabor that too much.
We have this big surge of water.
It happened at the same time of the impact.
Where it come from? What's the deal?
Basically, we know that the site was part
of the point guard system of a big river,
a very large river that cut deeply into the Hell
Creek landscape
and that emptied out into the Western Interior Seaway.
Okay. We already know that fact.
We know there was a big surge
that occurred in a couple of pulses.
We got bi
directional flow preserved in our sedimentary structures.
Most of our surge was going inland.
Essentially, that river was flowing backwards
during the greatest sedimentation
episodes of that event.
So we know that surge came from the direction
of the Western Interior Seaway.
It was flowing westward from an eastern direction.
And that's kind of like a tip off right there.
It's a tsunami like wave.
And it's turning out
that the seismic waves arrived
right around the time of this wave
that deposited the Tanis sediments.
So probably the seismic input was what caused it,
not a tsunami from the impact site,
but it's a seismic shaking.
We're not going to get into that too much with this one.
But basically,
this is what your cross-section would look like,
an idealized cross-section of the site.
Your white arrow out is going to give your flow.
The river easily documented all at the site.
Know you've got all your typical said structures
and then you've got your opposite flow from
the surge would have been about ten
and a half meters and it would have filled it up
like that, possibly more.
But that's what the fossil record shows us,
and it could have been even deeper than that.
We've got let's go back a little bit.
We've got CPG boundary preserved directly on top of the surge
deposit here.
We've got KPMG boundary preserved here
and the over bank deposit
and then also at the edge over at six at Brooke Butte,
which is about one, 1.1, 1.2 kilometers to the north.
So we've got KP boundary
sediments all over the place from site.
And there it is, filling up.
And we've
actually got some of our Marine fossils that show you.
Yes, this is probably a surge that originated from the seaway.
We've got freshwater organisms at. Right.
Like the sturgeon.
We've got this beautiful feather which came from
probably a bird or a man, a raptor and dinosaur.
We've got those mixed in with Ammonites.
It's a marine shelled mollusk.
We've got sharks, mosasaurs, different marine fish,
marine farming, afra, and things that just don't belong there.
These don't exist in the Hell Creek formation normally.
There are two marine tongues in the Hell Creek formation.
But the fossils, the timing
and the mode of preservation don't match with the site.
So there's no linkage there.
So we'll talk about the animals a little bit.
The biota of Tanis and the new insight into life
at the end of the Cretaceous based on that.
So we've got our connection
between the impact event and the biota,
and most of that biota turns out to be fish.
In this case, we've got a lot of
we've got sturgeon, we've got paddlefish,
we've got at least three new species of fish
that are unnamed at this point.
So we're already learning
about the types of organisms that existed back then.
But we're going to talk about a little more interesting things.
They are now the pterosaurs.
So these are winged reptiles.
There's a flying reptiles.
They existed back then.
At the end of the Cretaceous,
the Hell Creek formation had only one type
that we're aware of the as dark it's
that's the giant type
Quetzalcoatlus is one of the ones that's more
well known as the size of a small aircraft.
So these are big pterosaurs.
They're well known around the world.
This is a great example
of the basics of our knowledge of pterosaurs
from their origin all the way up to the extinction.
We know a lot about pterosaurs.
We've got plentiful remains and they are sort of like,
you know,
one of the favorite things to study,
the one thing we don't know a lot about
is what were their eggs, babies,
reproductive strategies and etc..
The embryos are practically unknown.
That is the temporal span of our knowledge
on pterosaur embryos, not that much.
We've got one Terra Astro embryo.
There are 18 embryos for the on the occurrence.
That's it.
You know,
that's all there is in the entire world
and none of them from North America.
The good part about the site is the preservation
potential is so good because that rapid deposition
that we are able to add a data point to that
and add the as darkens to the end of the Cretaceous.
So we expand this temporally and taxonomic lee which delights
us to no end.
So ahead graphically, this is where we are.
Most of our carcass tangle is going to be down here
at the upper part of the first surge pulse
and the lower part of the second pulse. That's
where most of the organisms are in this deposit.
Although, as I mentioned, some cross-cut
the entire deposit at an angle to the bedding plan.
So there's stuff throughout
that's just your main concentration.
The deposits capped by your Cape Town dean.
So you've got your pristine, uninterrupted
layer of impact debris.
And the embryo comes from right here within the upper
two thirds of the deposit.
And here it is.
So at left, you have a view.
It's about the size of a hen's egg.
This is a plain lite view of the embryo.
We can see the tangle of dark brown bones there,
which I'll show you later, are nicely
articulated in most cases
a brown halo for the shell, and it compares favorably
with the embryos that are found elsewhere.
So it right is one of the more famous embryos from Asia.
And it's a beautiful or if accurate embryo.
And the mode of preservation
and the style of folding is very, very reminiscent of the
Asian one.
When we look at the Tanis one
and here's a shot that Dave Berman
I got going with the laser stimulated fluorescence,
and you can see the
bones come out and you can actually see
some of the articulation.
So here you go.
You've got your
your upper arm bone, your humerus,
and you've got your radius and owner
and then the long wing elements that are preserved there,
they don't match anything that should be there.
They don't match the birds or the dinosaurs.
And the the structure of the bones
and the anatomy of this creature
really only compares favorably with the pterosaurs.
So we're relatively confident
and so is Davon, when our coauthor,
one of the world's experts in pterosaurs,
that this is a beautiful as dark and pterosaur embryo.
And so as scientists,
we just have to keep picking, picking,
picking away at the details
and figuring out what we could find out.
And with these samples
and with the ejecta, we ended up going
to two of the most powerful
synchrotron facilities in the world.
We went to Sorrell at Stanford University and the Diamond
Light Source in Oxford, UK, two absolutely gorgeous facilities
and I cannot say enough about
how wonderful they were during the analytical procedures.
Here we are at the beamline, scanning the specimens.
We've got the beam pipe here
coming out of the storage ring, giving us our
our lethal synchrotron radiation.
You don't want to be in there when it's when it's operating.
And we're able to find details with these methods
about the organisms and their chemical makeup
that you just can't find otherwise.
And this particular beamline
enables us to look at the chemical makeup
and the spatial distribution of those different chemicals
at a molecular scale.
And you're able to see what does that organism made of?
Is that material
organically bound or is it something
that's an artifact of the fossilization process?
We're able to take these things down
and look at all
these little things that normally you can't see.
And in this case, it's the sulfur.
So there's a blown up view of the egg blue.
You're looking at the bones of the pterosaur.
All of that yellow is sulfur.
And the sulfur follows the outline of your egg shell.
The sulfur in this case is not just sulfur.
We'd be happy if it was just sulfur.
But in this case, it's not.
Through the x ray absorption spectroscopy,
we're able to determine that
all of the sulfur you see on the screen was organically bound.
That is not sulfur.
That's a result of the Fossilization process.
It's not something that
precipitated or something
during the classification of the outcrop.
This is something that is tied to the organism itself.
Moreover, it's probably tied to the egg shell
because you would have had organic sulfur
associated with the whole organism, but
the egg shell would have been a little bit more resilient.
And we suspect that that sulfur is probably tied
to the cysteine in the the eggshell proteins.
We're going to be looking further into that,
going on to the shell.
Here's some shots of the shell.
And it turns out it's actually a dual layered shell.
This is a top down view.
And here you can actually see we're at the edge of the shell.
There was a little bit of a flake up that occurred.
And you can see there's the upper unit of the
shell and down below is revealed your lower unit of shell.
And that's basically shows
us a difference in texture, a difference in composition.
And you look a little bit closer.
You could get a closer view
of the upper unit of the shell top down.
And there it is
actually compared to a soft shell, gecko, egg, modern day.
And you can see them compared side by side,
somewhat similar to each other.
You look at them, edge on it,
can get a little bit of a better view.
This is sort of an oblique top down view.
You can see that flaked edge there.
And there's a direct cross-section
where you can see
a beautiful distinction between the upper and lower
layers, both in color and texture.
And that's even more illustrated by the ECM images,
because you can see
sort of this haphazard, grainy texture of the upper unit
and the lower unit.
You could even see little reminiscent structures of the
sort of parallel bedded
structure that would have been there,
sort of like the laminated structure.
And when you look at the seam and the elemental difference
between the upper and lower layers, the textural difference,
it actually compares very favorably
to the modern eggshell there as well.
That's a soft shelled snake egg, modern day.
And as we went through this specimen, we saw more
and more features
that signified that
this had a soft shelled egg similar to the early pterosaurs.
But now we know that that feature existed
into the latest Cretaceous, which no one knew until now.
And here we go. All right.
This is another beautiful view of the skeleton.
So this is a zoomed in view.
We can see the shell is outlined in zinc.
We've got strontium outlining the bones.
And the one thing to
remember here
is that the bones of this are really well ossified.
They're well-preserved. Well, ossified.
This was probably a late term embryo based on
how many of the bones were ossified,
based on the articulation, based on the size.
Probably was a late term embryo.
And when you see that much ossification occurring
late term,
that probably is an indication that it would have been
better able to fend for itself once it hatched.
It probably was not going to be helpless once it hatched.
And when looking at some of the dimensions
provided by other studies, this is where ours plots in
nature at all.
Did a beautiful study
on precocious reality and pterosaurs recently
and the tannis embryo.
Some of the
arm dimensions of that embryo actually plots very close
to the embryonic pterosaurs or hatchling pterosaurs, rather,
and sort of close to the trend line
for the non hatchling pterosaurs as well. So.
Long story short,
some of the preliminary data
about the wings shows us that it is at least compatible
with other pterosaur specimens
that would have been capable of flight.
This probably would have been a precocious organism,
and that's a good advantage,
especially if you're going to be
in an area where things want to eat you.
That's how big the thing would have been
when it was hatched. So this is the first reconstruction
based on the fossil.
And this shows the articulated, reconstructed skeleton.
The bones that were not present in
the original were reconstructed
based on the proportions of as dark and pterosaurs.
But we had representatives of a lot of these bones.
So it is a faithful reproduction of of how it would have looked
if it got to hatch a little bit skinnier than if it hatched.
But this is how this has been
basically the size of a bat one hatched.
So pterosaurs. Wonderful.
Dinosaurs are even better.
I think maybe.
I think they're on par with each other personally.
So let's talk about the dinosaurs.
From the deposit back to our trusty column.
We already have our our kapag boundary clay there.
We've got our main concentration of fossils down there.
Where do the dinosaurs occur in the deposit?
That's something we really haven't gotten into much yet.
Two places.
First, we've got actual dinosaur remains in the deposit
and the ones we're going to talk about here
come from right about there in upper unit one
at the very top of the very first search pulse.
And then we've got a very cool thing that occurs.
We've got trace fossils in the paleo surface right under Tanis.
So essentially when you've got this surge
that came in and covered that riverbank
and covered that point bar,
it covered the active paleo surface of the late Cretaceous,
whatever it was there got covered.
And in this case, we had footprints
in that paleo surface that got covered
by a beautiful contiguous layer of sediment.
These were not older footprints that were re-exposed.
These are not footprints that had formed any other way.
This is latest Cretaceous material.
And here's how that shakes out.
So at right, you can actually see this
beautiful angled paleo screen.
You actually see the angle of that point bar.
And this is the exposed surface because it's trampled
all over the place. It's not smooth.
It's like a game trail.
It's almost like you
go to a cow ranch or something today
and then that is directly overlain by that
veneer of the surge deposit, very different lithology
and the basil sands of that surge deposit
fill all of those cracks and then footprints
and totally different sedimentation.
And when that dries just a little bit in the sun,
it just pops right off.
And you've got all of the beautiful tracks beneath.
And here we've got some of them.
There's a three toed track from one of the dinosaurs,
and we've got the surge deposit resting right on top.
And, you know, what's the timeline of this?
You know, what we argue is this is probably not too long
before impact, not directly before impact.
If it was the same day,
it would have been a muddy deposit
and your surge would have washed that away
if it was too long before the impact
in this subtropical environment
that would have been raining all the time.
Those would not have lasted well in the record.
So basically they would have left these tracks in the mud.
The mud would have dried for long enough
that they would not have been washed away by the surge,
but it wouldn't have been too long.
So we're talking weeks to months, probably.
Near some of those beautiful tracks, theropod
dinosaur tracks.
These are the carnivorous dinosaurs.
Dave Burnham's hand for scale.
Next,
that beautiful trade, tactile print there we got on
at the moment over there.
So we've got the meat eaters represented.
These are probably from herbivorous dinosaurs,
but they're not yet determined which taxa they're from.
But, you know,
the fact of the matter is,
we've got a diverse assortment of dinosaurs,
so we don't
necessarily have to identify the specific taxa right now.
We've got to identify more fat types.
And that gives us an idea of species richness.
You know, how rich were the dinosaurs right at the end?
This gives us a very good idea.
Not only that,
we also have infant dinosaur tracks, so infant hadrosaur.
And we've got infant either
serotypes in or it could possibly be mammal,
but it's probably Sarah Thompson based on the man's prints.
And when you look at the scale, these things are about
the size of a silver dollar or a golf ball.
Very, very small.
That's from a baby that would be about that big
and that would have been from that year's breeding season.
So those are babies
from the last breeding season of the Cretaceous.
And you know that they were living there
not too long before the surge.
So about the triceratops.
Yes, they existed in the area
and yes, they died in the area as well.
So while excavating into the surge deposit,
we identified some soft tissue associated with those.
So we ordered reported a partial hip from a set of topsy
and in that deposit and some soft tissue associated.
Well we wanted to go back
and find more if there was more there and more there was.
Here's Riley.
We're one of the grad students at FSU at initial contact
with this beautiful, scaly pattern, from what we now know
is Sarah Thompson.
At that point, we knew it was from a large dinosaur.
And here we have
Lauren virtually continuing that excavation
and this protuberance on the top of the very,
very large scale
that is very similar to what you would see in triceratops.
I've not seen it in any other Sarah autopsy.
And personally, it's almost certainly from a triceratops.
Like, oh, well, how much is actually there?
We ended up getting lots of skin from this animal.
We got a selection of bones, which shows us that
we had an associated skeleton at one point in time.
And that animal probably died right there,
probably was not transported in like we originally thought
with that many bones representing
that much of the skeleton know probably not transported in
but died before the impact.
This was not something that was part of the
asteroid impact at the end.
We had a lot of decay.
The bones were disarticulated
and this animal probably died weeks, two months before impact.
Again, like with the trackways,
you're not going to have this die years before impact
because all that soft tissue would have been decayed away.
You would not have had an opportunity to rework it.
So it was not a fossil at that time and reworked.
So we're looking at probably weeks to months before impact.
So sadly,
that was not something that died in the impact search.
But we did find something that probably was.
So here's some of the new stuff.
We've got Dave Burnham's thumb
for scale next to soft tissue associated with bones
that later turned out to be from a dinosaur.
And after much digging, this is what the sediment
looks like when you start.
You know, it's really this awful mess
and you have to make sense of this
and you have to do a very detailed excavation over time.
We ended up revealing
a herbivorous dinosaur in that deposit, and here we are
delineating the block with a herbivorous dinosaur.
There's actually a palm frond over here,
and we're delineating the creature.
This is the outline of the rear leg.
So we have the thigh going to the calf.
We've got the gastrocnemius would have been there.
We've got the ankle and the toes all the way down to the claws.
And this animal was preserved in such a way
that you had these
three dimensional skin impressions
over the articulated skeleton,
meaning this was not decayed prior to impact.
It was not decayed prior to deposition.
It was beautifully preserved.
And we did not know exactly what it was we know
was a herbivorous dinosaur.
We narrowed it down.
It's probably either from a packing surplus store
or a vessel, a saw.
So those are two
herbivorous dinosaurs, sort of like a gazelle echo more
from the Hell Creek landscape.
And they would have been gorgeous little creatures,
but we weren't quite sure which type it was.
So we dug deeper,
figuratively speaking, and did some micro CT work.
These are micro TS, literally a digital dissection
of this dinosaur.
So this is like a dinosaur CSI.
This is the beautifully articulated toe of that dinosaur
inside the three dimensional fossil skin envelope.
So you've got all the digits of the toe,
you've got the claw here, you've got the ankle at right.
You can see the leg
partially flexed
and you can see some breaks in the leg
that are from Fossilization.
But there are some green stick fractures in that.
Those green stick fractures are from the time of death
before Fossilization So it actually had trauma
before Fossilization
And this
turns out to be from a dinosaur called a festival source.
That's what this thing was from.
And here we've got a compound fracture of the femur
from before death,
and we've got all these beautiful skin impressions
there.
We've got the top of the foot with these overlapping
screw scales like you'd see in a chicken
or an ostrich foot today, just like that.
And here we have it, 66 million years old,
preserved in this dinosaur that most likely experienced
the worst day that a dinosaur ever could experience.
That dinosaur probably witnessed
the impact event in its own special way.
That's also teaching us new things about this resource,
in addition to teaching us about the impact.
Because the scale patterns we're seeing on
this leg are scale patterns we've never seen before
in a herbivorous dinosaur.
So we're able to actually reconstruct better
than before the appearance of the leg of a Tesla store,
because we've got these
very elongated, tubercular scales,
which probably would have
equated to some sort of a pattern of color
or something like that in the animal.
They at least would have been a texture pattern
that would be visible on the animal,
possibly a form of camouflage.
No one knew they had that before.
So because of the preservation here,
we're actually able to determine
new things about this dinosaur.
And then we have to go through our list of our dinucci.
What caused the death of this thing?
We don't want to jump to conclusions and say, Yeah,
yeah, this is something that was brought down by the impact.
We're scientists.
We want to figure out and weed out
what is incompatible with what we're looking at.
Predation could have been preyed upon.
You know,
lots of herbivores are in this case, it's not well-supported
by the fossil.
We don't see tooth marks.
We don't see anything that indicates that it was
either partially or completely consumed.
You know,
we don't see evidence
that a predator engaged this animal or shed the teeth of
the predator. You see those sometimes two.
We don't see that.
How about disease?
Was a disease
could of died right before impact
maybe a day before a week before a disease or animal?
Well, Paul Barrett and other people
actually have examined the specimen,
and they they agree with us that there's no obvious
evidence of disease associated with the leg.
It looks like it was an animal in good health.
It looks like the animal probably,
you know, was just a normal average
sessile sort just living out its life.
We don't see any obvious signs of a bad disease,
so probably not disease.
Okay, how about trauma?
I just mentioned trauma. We do have trauma.
Yes, we've got green stick fractures.
We've got fractures that occurred at the time
or right around the time of death.
Good. Okay.
That gives us a little bit of evidence there.
And could this have been contemporaneous?
It's compatible.
Now, as a scientist, I'm not going to say yes, 100%.
We do have an animal that died in the impact search.
Is it compatible? Absolutely.
Because we've already weeded out some of the most
obvious causes of death and it's compatible
that it could possibly plausibly have been
a victim of that impact surge.
It did not decay before burial.
That's that's one good point of evidence.
So that is really kind of an exciting thing to think about.
This creature could actually have experienced that event
this rather than thinking, Oh yeah, the impact caused all
this extinction.
You're thinking, Wow, how did the impact affect
the life of this single creature?
And that brings it down to kind of like a human level.
Now back to the impact itself.
Let's talk about what the impact tells us about the impact.
The ejecta spirals, the beautiful ones
that are totally preserved in glass,
that are not altered at all into clay,
have a little bit more to tell us.
They're not just pretty.
They actually have data to provide.
This is the exterior. We actually still have
some pieces of amber adhering to those.
There's the interior with some beautiful gas bubbles
in there like we typically will see in the impact melt glass.
I'm astounded at the beauty of the interior of this thing
because when you look at that glass,
you can just
imagine the day that it was flying
through the air out of the crater,
out of the atmosphere and solidifying,
you know, as a little piece of glass.
But there's stuff in there that is really important
to us as scientists, and that's the inclusions.
We found bits of rocky debris in several of these
that we're like, okay.
Just like you see an insect, an amber.
Now we're seeing a piece of rock inside the glass.
Perfectly preserved.
What's that going to tell us about the impact?
There's a little nugget there.
There are all these little dirty nuggets in there.
Every single speck
that takes away from this beautiful
clear glass is a piece of debris.
And that's essentially the equivalent
of sending someone back in time
with a sample vial to the point of impact,
collecting a sample, bottling it up
and perfectly preserving it for scientists right now.
And that's like research gold.
So what we found
is that almost all of these little un melted
nuggets are enriched in strontium and calcium, and
they are parts of the carbonate platform of the Yucatan.
They're part of that limestone platform that got hit
and got thrown into the air.
These are pieces that didn't melt all the way.
We expect that.
It's very cool, very amazing.
For all intents and purposes, those are some of the best
preserved pieces
of the Yucatan platform that got hit
because they haven't been weathered in 66 million years.
So you've got those little bits
of evidence from the moment of impact,
and it brings you kind of closer to,
you know, feeling like you were actually there on that day.
You can picture these being encapsulated
by the molten glass.
But when we were at Diamond Lightsource in Oxfordshire,
we found a couple of
of these fragments were not quite what we expected.
Two of the spherules had fragments in them
that were wildly different in composition than those others
that were not enriched to the calcium
in the strontium like we would have expected.
These were rich in the iron.
They were enriched in chromium, the Irish nickel.
And a few other things I'm not going to mention just yet,
but these fragments matched what we would expect.
From elsewhere, not from Earth.
And as we go
through the micro analysis, we can demonstrate that further.
This is an awesome view of one of those fragments.
We actually have a control or what appears to be a control
that is preserved within this brush created matrix.
And we have the dark region around the exterior,
which is likely related to the fine grained rim of the control.
We've got a closer view.
That's a much better view of the control.
Actually.
We've got some chromite along the the edge there.
We've got beautiful view of the brush shaded matrix,
really nicely formed control and probably olivine.
Actually, it probably is.
We've got enrichments of of manganese or magnesium there.
Beautiful brush headed matrix.
We got control. Control.
And this is our view of one of those fragments.
So the micro structure is going
to tell us a lot about where it came from.
And you'll be able
to do some of your mineralogy with your EDC data and such.
And the ratios of those elements to each other
tell you a lot about what these things are made of.
And obviously we don't jump to conclusions with these.
We let the instruments tell us what they tell us
and the specimen will tell us what it is.
So far, the data is showing us that our sample falls
within this region, which is the carbonaceous chondrites.
So most likely this particular sample
is allied with the carbonaceous chondrites.
And that's good to know
because that actually falls in line
with what Frank Kight was telling us years ago.
Kate, describe this sample at right,
which was found in the Pacific in a drill core 9000 kilometers
from the site.
That's like three times farther than Tanis,
and it's a little larger than mine
fragments, about two and a half millimeters.
I don't know how two and a half millimeter fragment
would have gotten that far,
but assuming this is actually from the impactor,
there is some data we can get from it.
The problem is this carbonaceous chondrites are not resilient.
They're not nickel iron meteorites.
They fall to hell in the environment.
They hydrate, they alter.
And this piece is no different.
That particular specimen went through 66 million years
of being ravaged by the ocean waters
and the deep sea sediments.
There's no original mineralogy that exists.
There is a lot of
chemical exchange with the the exterior matrix,
and there's no way really to tell exactly what type it is
except probably carbonaceous chondrite.
And he proposed it's probably either ac0 C.R.
or c m subtype carbonaceous chondrite.
That's good.
That's good to narrow it down
a little bit further, but still, it doesn't really give us that
final oomph.
You know, do we really know what the asteroid was?
And our current specimen
falls within this region of the graph.
And this is one of the many different analysis.
I'm not going to bore you with all of them,
but ours falls within that region,
which identifies it as most probably a CM
type carbonaceous chondrite, which is excellent
because that actually falls right within Frank Kite's range.
There's Frank Kite's proposed region and we go right here.
So we probably do have a CM carbonaceous chondrite.
And in addition to that, just being a phenomenally cool
aspect of the impact story, you're able
to look at a fragment, even if you haven't identified
that fragment and say this is a of of cosmic origin.
And almost certainly this is related to the bolide
that hit at the end of the Cretaceous.
That's amazing. It's phenomenal.
Then if you're able
to actually identify it
and we're on the road to doing that,
then you can actually say, Amazing, we know what it was.
But it's not just cool that actually has some significance
because when that asteroid came in, you're looking
at a ten kilometer diameter piece of rock.
The composition of that rock is not trivial.
The composition of that rock,
when it was vaporized and went into the atmosphere,
contributed that atmospheric perturbation
that contributed to whatever happened to Earth's biota .
So knowing what that composition was, was it high in sulfur?
Was it high in something else? What actually went up?
You can combine that with what you know
about the Target Rock and have a better idea
about the dynamics of what occurred on the day of impact
and why the things happened the way they did.
So this is an important step
forward in our story of understanding
about the entire impact event.
And one thing that we do know is the impact
did not have a very good effect on Earth's biota.
It was not compatible with life.
It led to the massive extinction.
I'm going to go through these very rapidly,
a couple of high points about this pterosaur.
Again, this is the first pterosaur
embryo from North America,
the first one from the late Cretaceous Worldwide,
the first one from Nasdaq, a pterosaur.
There's a lot to learn from this.
And also we're talking about when did the impact hit?
You know, the impact occurred
sometime in the spring, the summer months.
You know, we we actually just performed
a study that determined that's the most likely range.
And there are a whole bunch of vulnerabilities
that are inherent to that time span that are going to occur.
These things are over obvious.
They do have precocious, young, probably.
How does that affect now? We can actually postulate?
Well, you know, we can figure out
different ways that could have been affected by the impact.
We look at the vessel saw, basically
we've got a dinosaur at the KPC boundary.
It closes the gap and usually you don't
find dinosaurs right at the big boundary.
You've got a significant gap.
This closes that gap completely.
In addition,
we've got
details about that particular
type of dinosaur that weren't available before
and this could have been killed.
By the impact.
That's some significance right there.
Very, very interesting.
And also, if we do histological studies on the bones,
we can work backwards
and find out what things were like
leading up to the impact in the environment,
because the growth lines
in those bones give us a record of that animal.
Then, of course, the fragment is a beautiful map
of one of the fragments inside the sphere.
And, of course, that fragment is going to tell us
more about the dynamics of the impact event.
What the asteroid was made of and possibly how it could have
affected life on earth.
And this gets us so excited
because we know the asteroid caused the extinction
at the end of the Cretaceous.
To see a piece of
the culprit is just a goosebump, bumpy experience.
And lastly,
the story that's
kind of brought forward
about this whole event in the Cretaceous
kind of comes full circle.
It's not just about the late Cretaceous.
It's not just about what happened back then.
It relates to today as well,
the mode and tempo of the extinction event.
It is very, very similar to what we see today. The.
Rapid.
Damaging effects to the ecology today mirror
to a startling extent what we see in the fossil record
for how fast
the extinction event occurred in the Cretaceous, much more
so than the other mass extinctions in Earth's history.
So that is a startling thing, and obviously it's up to us.
We have the capability of doing something
about that and learning from the fossil record.
And it is indeed the fossil record
that is our way to learn how to do something about it.
We are the only species on earth
that's ever been able to learn from this.
It's up to us to do it.
And the fossil record is our way of looking back
into that window of time
and actually seeing how to Earth's biota.
How do these animals and plants,
how do they react to a global scale hazard?
It's not a simulation.
It's not a question mark. It's not a hypothesis.
You're actually looking
through time at the fossil record to see what happens.
That's our best way of understanding
what's happening today, what could happen today,
and how could we have an effect on that.
So that's our obligation.
And with that, I will thank
the following individuals and all of you as well.
Thank you so much.
Thank you so much for your presentation.
Thank you.
I think a lot of you understand
now that a number of us had trouble sleeping last night.
These results are so exciting.
I think you can say that
these are some of the most significant results
in our century
and to to really nail down what happened on that day
when we were struck
by this tremendous now better identified asteroid.
So that was incredibly exciting.
Thank you so much for your presentation.
We will have questions, questions and answers later.
So we'll take a break now.
Thank you.
Hello and welcome to NASA's Goddard Space Flight Center.
My name is Michelle Thaler,
and I'm here to host the question and answer period
about some extraordinary findings
about the date that the asteroid hit
that made the dinosaurs go extinct.
And we have Robert DePalma here
in his team, have just had some incredible discoveries.
I'm still speechless, I have to say.
There were so many things that when you were talking,
we were just emotionally reacting to people.
I saw I saw Christa was
she was nodding and she was going, oh, my God.
There was just amazing evidence today presented
that you have captured the moment that asteroid hit.
The ejecta came, seismic waves ripped through the planet
and some of these organisms were swept together and died.
I mean, it's amazing to be
standing in front of that right here.
So this question,
the question answer period can start many different ways.
But one of the things that I wanted to begin with
is that just putting the science aside for a second.
There's
this quite interesting personal story
here for you, too,
because as you began to look into this deposit.
Well, for one thing, I understand
this deposit was thought it was kind of confusing.
People didn't know what to do with it.
And so a lot of scientists kind of
didn't want to work with it, didn't seem very clear.
You stuck with it,
but your findings were controversial
and you got some some pushback about.
Can you tell us a bit about that, that journey,
about people being skeptical and now people being
very excited about these?
Science is about being skeptical.
You really have to ask questions
and don't take anything on face value.
That's what happened with Alvarez and everybody else
when they first proposed that an impact occurred.
Nobody agreed with it.
And if everybody agreed with something,
I'd be kind of worried.
That's that's when people weren't
really thinking critically about it.
In this case, what you do and what you do
as a scientist is you find what evidence lines up.
What does it mean and what does it tell you?
You don't tell the story,
the evidence, the fossils, the data that tells the story.
And the longer you work on it and the more of all of
those items you collect and you are able to interpret,
they are actually forwarding that information forward.
And in this case, all of the data,
the information that different teams
are putting together, our team is interpreting
based on these specimens, all it's coming together
to sort of support this rich story
that is linked with the end of the Cretaceous,
the end of that time of dinosaurs.
It's a very
calm and very
measured scientific response, I have to say.
To me, it doesn't match the excitement
I feel about this.
The joy, I have to say,
a bunch of us were just jumping up and down
when we heard about this and what was going to be presented.
So there's also an emotional story about,
you know, as you began to piece these things together,
realizing what you had found.
Can you take us a little bit on that as well?
When looking at the fossil record, usually you're looking
at really long timescales, millions of years, tens
of thousands of years.
And really, as paleontologists, we are passionate
about the animals.
I am passionate about the animals
and whatever was existing at that time.
So whenever I'm able to look at something
and kind of have a fossil in front of me
and be able to tell what that animal experience,
what was its life like?
What did what happened during its life?
How did it die?
That's a special thing because it gives you a window
into that animal's life. There's one creature
experiencing what another creature did.
And in this case,
all of these animals
that are just tumbled together in this deposit
sort of had what I like to refer to as a front row seat
to one of the most magnificent events of the late Cretaceous,
the impact event and its aftermath.
And how did it affect them on an individual level?
And that's just such a personal story.
Each one of them
would have experienced it a little bit differently.
And to see that kind of develop in front of your face,
in the outcropping in the lab is a really personal experience.
You're there and you're listening to that animal story.
There's something really immediate about this.
Again, I'm looking down on a specimen of a fish,
and you pointed out to me that there are tiny
little spheres of glass stuck in its gills.
You know, that this creature died, it suffocated
because its gills were clogged
with ejecta that had to do with this
huge impact, this asteroid hitting the earth.
And there it is right there.
You know, these things had this
you know, they died, we think, because of this happening
like we were talking about today.
You're looking at this moment
and we were all just mentioning this even
while we were having lunch together today.
This was a moment our ancestors also experienced.
We we are related to things that lived through that day.
And, of course, things changed incredibly, this incredible
rich ecosystem dominated by the dinosaurs that went away
and this mammalian ecosystem begins to become more dominant.
So we're looking at an amazing change.
Maybe we wouldn't even be here talking about this
if that event hadn't happened.
If you put your finger
on a single point in time in the rock record
and say that point was absolutely pivotal to the world,
this was one of those points because you can literally
get your finger and put it on the Cape boundary grade,
the impact fallout and say, that's your dividing line,
that's your pivotal moment, because you're absolutely right,
the mammals rising up and being able to diversify that
massive shift in ecologies and ecosystems across the globe,
they're tied to that moment, to that impact, and
to see these animals
that would have experienced that event
and then to look closer, like you say,
and you can
see some of the impact debris packed in the gills of the fish
so that fish interacted with the impact debris.
The whole story is there.
You've got the impact that caused that tremendous shift.
You've got the animal that experienced it
and then you've got all of this in one layer
that gives you a moment by moment record of the aftermath.
You've got this layer cake of an incredible story.
So just kind of give people a chance
to start asking questions.
We have we got Dr.
Jim Garvin, who is the chief scientist here at NASA Goddard.
I was sitting next to you during the presentation.
You were reacting.
You were really excited. At one point.
You actually were almost like at the point of tears.
What are some of the moments
you remember that that you were looking at
the evidence thinking, wow, look what they have?
Well, I think what Robert's done with his team here is connect.
The way we looked
at the history of the rock record on Earth
as defined by life in these names of errors
we all grew up with
that became known as Cretaceous and Triassic
and all that
to the record of Impact
This Life on the Rocks cosmic collision story
that we've already used on other worlds.
How do we define the errors on the moon?
We named them for the errors of impacts
that defined different time horizons.
We've made a link now beyond our planet
through the lens of the bigger universe.
Roberts Stuff now starts to give us data
I see for that connection being expanded.
So, you know, maybe CBGBs, the wrong name, maybe
should be the big C for Jigsaw because it defined a change.
And those connections aren't only at the big animal scale
in some of your findings,
but also the microbial scale and how we read those records.
I can't wait to see what you learn, because my question is,
you found preserved elements of this micro comminuted
impactor that made this event that changed the course
of the history of life.
You played the tape backwards.
We wouldn't be here to quote a certain Yankee fan.
So what do you think about those?
I mean, that's a finding of cosmic significance.
It's Mother Nature's
best sample return to give us a little piece
of what she did to change the course of life.
I mean, why don't you tell us about that, Robert?
Well,
to find any sort of material
that's associated with the impact event and really
well preserved fragments like
the cosmic material we've got, it is like going back in time.
Getting a sample vial and getting material
from the site of impact and being able to study it
and working out the dynamics of the impact
event itself is incredibly, incredibly important.
That is paramount to understanding
how that impact affected
life on Earth and how natural hazards
are going to affect global ecosystems.
But it is a tremendously moving kind of a feeling
because you are literally connected to these moments
in time that are better understood now,
but still poorly understood in many different ways.
And they interfere
with so many different aspects of science and life.
So these questions are incredibly important to answer.
And as the answers are kind of flowing out, each one
kind of builds the excitement an
Well speaking, leading to more questions.
So there were people here that were paleontologist
Jim that were asking you about meteorites.
So so where where would this meteorite have come from?
Does anything about the
the structure,
the analysis they've done,
does that give you any clue about the history,
the structure of the meteorite, this kind of meteorite?
Well, Robert
Roberts and his team showed us that this is a carbonaceous.
We think from the preserved evidence
in those time capsules of amber within a sphere rule
that was made by the by the impact ejecta.
I love the impact ejecta personally. It's very moving.
Didn't want to experience anything
like the gills on the fish, but not monster.
So there is a little piece of those things
that we're now going to to sample what they tell us.
We just completed sampling the asteroid bennu.
Not as big
as the one that hit the earth and takes a little granted,
you know, less than a kilometer across.
And we're going to bring back those materials
to study in the way Robert is studying
the impactor that made this cosmic event.
So those connections
to that part of the inner solar system
that records that stuff,
those artifacts of the collisional history of Earth.
You know, he's got it.
So we're bringing it back.
Thanks to robotic spaceflight.
Wonderful job by osiris-rex.
And just a little deposit, a little sample of our own
for us to study and maybe other impacts.
Other ones not as consequential, but equally interesting.
Just in the last 40 years, understanding the role of impact
in the history of life, climate
and all that is a profoundly new change
that was heretical, as you said, Robert.
It was you know, you got to be skeptical
because everyone was telling you that's not the way it was.
And so I think I don't know.
Your work is showing us what could could really have been.
And that's the way science works, changing paradigms.
Also with us, we have Dr.
Krista Peters
Ledgard, who is our deputy director
of science at our science exploration director here.
And you're a hydrologist by training as well.
So so what what are some of the things that jumped out to you?
Oh, yeah.
Well, I mean, thinking about the storm surge.
Right. You know, and the power of water. Right.
Ten meter high deposit.
And just thinking about how,
you know, what the bed load was like.
I mean, there was there were logs recovered at the site.
I mean, just the power of the of the water in this event,
magnitude 11 or 12 earthquakes.
I mean, it just it's just blowing my mind.
So, you know, one of the things that occurred to me is,
you know, you have these two deposition episodes, right? So,
you know, how how did the
composition change, you know, from those two episodes?
And what what does that say about, you know,
the physics of the surge in those two episodes?
That's a phenomenal question.
And that's one thing
that we've been thinking about quite a bit.
The sedimentary record is going to give you
the details about that story
and the grain size and the bed forms
and everything else you get there.
They're going to tell you what it was like
if you know how to read it.
And in this case, we had two pulses to that surge.
There was one initial pulse, it back flowed
and then there was a second long pulse.
And we know that they occurred right after each other
because you have animals and plants
that would have been very delicate
that cross-cut all the deposit.
So you're not going to have
a long hiatus between those two pulses.
And then when you look at the pulses,
there's a little bit of a difference in composition.
So the first one was much more turbulent.
That first pulse
had a lot of rip up class, had a lot of sand content.
The grain size was a lot, a lot bigger.
So you had a much more turbulent surge,
the second surge, more mud, more clay size particles.
And it appeared to be a longer surge.
So this massive, really bad turbulent surge backflow
and then a longer, more protracted
final surge before it slowed down
and all the water's receded, leaving this veneer
of mud and animals and logs and everything on the landscape.
Really cool.
Long live the lodge. Yes.
We also have Dr.
John Mather, the other senior project
scientist for the James Webb Space Telescope
and and a physicist.
So, John, what's your take, bringing the physics into this?
Oh, my goodness.
I'm excited, extremely excited to see the evidence that we've
now got for the details of what happened on that day.
Because this is the first chance we really have to check
all the incredible calculations that people can do
with hydrodynamics and simulations
of computer versions of rock hitting the earth.
But I'm also led to think about implications for our search
for life elsewhere in the universe,
because, well, it was pretty tricky here.
How much could we forecast? How could we predict?
So if we're going to look for life on other planets,
are we going to imagine that they're just sort of
sitting there passively producing life?
Or do we imagine that they also have a chaotic history
with crashes and evolution and extinctions and disasters,
one after another of the same sort that we've had here.
We've had Snowball Earth, where Earth was frozen solid.
Apparently, we warmed up.
We've had huge changes,
catastrophic to everything that lived there at the time.
And here is one catastrophe
we can examine in detail because it happened so quickly.
But we should
we should be
picturing catastrophes everywhere
that we're looking for living things, not just here.
So look on Mars, look on on Europa, look on Titan.
And look at the other places
that are interesting as sources of life,
catastrophe everywhere.
So and you're thinking also, what does it feel like to be
there as a living, sentient creature experiencing that day,
which is something people
I don't think can fully appreciate it
because you feel it and you see it.
You think, I'm like an animal there.
I'm feeling the heat, I'm feeling the water.
And I don't think we've really been able to
picture that part in the past.
So thank you for making that so possible for us.
It's an absolutely fascinating thing.
And you mentioned life on other planets
and how a catastrophe might play a role
that could also go the other way in that
the frequency of certain levels of catastrophe
could have a positive effect in some ways,
because those could actually spark different changes
in the evolution of life on those planets.
So in the short term, meaning in the,
you know, million to 10 million years scale,
it might not be so good for those that are experiencing it.
But in the grand scheme,
that actually could bring about different changes
in the trajectory of those evolutionary schemes
and bring about different innovations.
So it's really fascinating to think how that interplay occurs.
And also just finding the evidence for it.
I mean, one of the things that really
you know, I worked on the the Spitzer Space Telescope,
which is an infrared telescope, and we would see events
where there would be this huge
blast of heat from a young planetary system .
And really,
the only explanation was that two planets had collided,
and that was something that seemed impossible.
But then when the lunar samples were brought back from Apollo,
there were possible clues of that.
Having been the origin of the moon,
we wouldn't have even known what could have happened
in an exoplanet system.
Have we not been to the moon to get that sample?
So, I mean, the tremendous cataclysms that drive
the formation of planets, the evolution of life.
Well, and Goddard thought that the small craters on
the moon were volcanoes
and described them in his is motivating some of his work,
leading to the rockets,
the early fuel rockets that led to what we have today.
Didn't realize
that the mirror were impact basins that we speak with Robert
has shown us here on earth can do to a life bearing system.
So I think that's stunning.
We're becoming aware. Yeah.
And then finally, we also have Dr. Gavin Schmidt.
He works for the Institute of Space Studies up in New York.
And the director, I should say, that is works there.
But we were
we were talking a bit
earlier in the day,
and you had all kinds of
questions that were coming into your head
about what would the atmosphere have been like,
how would the chemistry have changed,
and what are some of the things that stood out to you here?
So I'm very interested in the climatic impacts of this.
So so I mean, we've talked about the the instantaneous impacts,
you know, the fire from the sky, the impact, the the
the earthquakes, the sizes in there in the water.
But, you know,
some things will have survived that,
but they might not have survived all the
things that came afterwards.
So what happened to the carbon cycle?
What happened to
things in the stratosphere?
How long and how deep was there an impact?
Winter? Was it warm? Then it got cold.
Then it got warm again.
What happened to the carbon dioxide
that was released from all the fires?
Was that the cause of the acidification events?
And I think we haven't really been able
to kind of piece together that history
in very much detail so far, because we haven't had,
you know,
specific information from the time event itself,
which I think this is going to help with a lot.
But we also haven't had the models or the understanding
of how all those things fit together,
particularly in a Cretaceous context,
for us to be able to do that.
So really, it's only in the last five or ten years
that all kind of global scale models
have enough physics to be able to answer these questions.
And that
and then this information coming in kind of really primes
the pump for, I think, future explorations of that
of that whole series of cataclysms,
because you've got the impacts,
but then you've got the winter, then you've got the starvation,
then you've got the fires and whatever order, you know.
And maybe, you know,
there are some places that were refugia,
maybe there were some places
that were not affected by some of these things.
And maybe we can learn a little bit more about,
you know, just even the short term changes that that occurred.
And like climatically, it's the same processes
that, as you say, that we're changing now
through a different mechanism, you know, changes in carbon
dioxide, changes in ocean acidification, changes
potentially in stratospheric input if we ever decide
to to geoengineering our way out of this,
all of these things, the extinction events,
all of these things have parallels to the impact event,
but also to some of the other
kind of interesting events
that happened in the Cretaceous or or in the years.
But that, you know, it's a fascinating tableau
for us to be able to build credibility
in our understanding of what's happening now
by by explaining what happened then.
I couldn't agree more, and I couldn't
say it better than you just did.
I absolutely agree.
And and adding to that,
you know, you're talking
about all these
different processes that occurred afterward
and you're talking about injection of
of different debris into the atmosphere.
Every little tiny step forward, we're going to add more data
to that.
And by we, I mean the whole scientific community.
And that makes that a more complete picture.
And part of that is
if we do have these pieces of cosmic material
by ascertaining what they're made of,
what's the makeup,
that's what's being
injected into the atmosphere along with the target rock.
So that's
helping us to better constrain what was being put up there.
And by studying other things at the site, including the PGE
boundary, that's that's capping the deposit.
We're working on kind of constraining
how long that impact winter would have been,
how long would the blockage of sunlight occurred.
And we're actually kind of fine tuning the previous data
that's been collected on that.
So hopefully that gives us some really interesting numbers.
But obviously
all these factors come into play of how these poor things
had to weather those first years, ten years, you know,
100.000 years. whatever it was.
And that applies exactly like you said to today.
Yeah. Yeah.
I mean, you mentioned earlier
that there's some evidence that this happened
in the Northern Hemisphere spring. Right.
That's that's kind of interesting, right.
Because the impact itself is quite close to the equator,
but in the northern hemisphere.
And so what does that mean
for how much this debris spread across the hemispheres?
You know,
maybe in the southern hemisphere,
you know, things were a little bit
different and maybe not so dramatic.
I mean, there's a
there's a lot of things to explore by looking at
the details of what's coming out of these new studies.
Think as well
about the trajectory
of the impact and the angle of impact of this bolide.
There are some impact angles that are incompatible
with any fragment surviving the impact event,
and there are some that are somewhat compatible
and there are some impact
angles that would lead to a much better,
you know, likelihood that you would find a fragment.
So the fact that we do have a couple of fragments
kind of helps us to constrain that a little bit better.
I know there have been a bunch
of different ideas put forward in the past.
This might help us to kind of weed through those
a little bit better and have an idea of what
that impact angle would have been.
And of course, in turn, the angle of impact has its own
set of implications in itself.
I think one of the sidebars of what Gavin and he was saying is
so we think by theoretical physics
that this scale of impact 10 to 20 million megatons
of TNT equivalent
would have mostly blown off the Earth's atmosphere
as it existed at the time.
It's all gone.
What happened?
It obviously didn't do that
completely because life persisted.
You have the most record in your stuff.
So what was the early time like?
Because, you know, we're also dumping gigatons of stuff
into the stratosphere, mostly from the target,
which was the carbonate bank with ocean waters and all that.
So that's the primary load, not the impact.
That's a little thing.
It's excavating to 30 kilometers in the quasi oceanic crust,
only grabbing at 30 kilometers down,
probably the transient greater.
Absolutely.
So on. My God.
I mean, now
we're through the skin of I mean,
like the continental crust by the oceanic crust.
Be right through it.
So, you know, God forbid, what does that all mean?
You know,
and these are the implications of that early time life record
and the chemical record you were getting to.
Any of that's preserved,
those are going to be
those model constraints that we can use for models that,
you know, that can produce where everything's going.
But what else is going on?
You know, they got down that deep.
I mean, did it actually like
was that like a volcano that hit magma or something?
Well, it would have hit whatever's at the 30 kilometer
depth in the transient cavity propagation, like Robert said.
But then the excavation stage moved this massive stuff out
and rippled it through over a period of a few hours.
And the resonant thermal pulse
was probably,
you know, thousands of years in that region, in that area.
So that Relic's scar is going to be part
of the Earth's history in that region.
You're 3000 kilometers away.
So that's a great place to look at the consequences
without having been,
you know, eradicated quickly or more quickly than you'd like.
Probably didn't feel a thing.
Well, I don't know if anybody likes to be eradicated, right?
No, no. Eradication
eradication is not.
Yeah, there's no that's not a good thing.
Well, actually and Christo,
as the hydrologist, we were talking about how
they were fresh water animals and saltwater animals
all mixed together. Yeah.
So so this really was a catastrophic flow
of a saltwater body into a river system.
Yes, exactly.
So, I mean, that that's
that was such a compelling piece of evidence here.
Right, that,
you know, that
you see these species together that shouldn't be together.
And, you know, again.
I like it. It made me.
You know, curious about how I mean, it is
it was sort of a jumble of of lots of things together. So.
I mean, as you approach this jumble and you started to say,
wait a minute, that shouldn't be here.
Like, how did you approach?
You know,
going forward, once you started to realize like, wait a minute,
this is different, this should not be here.
Well, before there was anything involving the impact,
even in our brains, the two real red flags are okay.
You've got a river that would normally run somewhat
east and it's running westward now
based on the flow direction that that doesn't make any sense.
And you couple that with the fact
that you've got Marine fossils there, microfossils, you've got
dinoflagellates, you've got form and infra,
and then you've got Ammonites and other things,
mosasaur pieces and and marine fish and sharks teeth.
You've got all those marine fossils mixed in this deposit
that was created by a westward flowing surge.
And obviously, it's not supposed to be that way, right?
That's not the way rivers usually behave.
So it's an exceptional event that got us thinking,
what the heck went on over here?
Why did the surge occur?
And then we were finding ejecta
and different things that connected it to the impact.
And then there was the cap of the big clay, like, oh.
Oh, what's that? Yeah. Yeah.
I bet you reacted more dramatically than that.
I mean, you're talking about
wanting to be in the minds of these creatures.
I want to be in your mind as you started
piecing this together and like, oh, my gosh, that's
that was a wild place.
Yeah, I can see the part.
So did you find this site or was that was it found in Matt?
But people didn't really know what it was.
The site is actually
a really incredible story and it's actually
a beautiful situation of how things really should work
of people working together.
I worked on a site for my master's
thesis that dealt with really fine time
scales in the fossil record,
and we wanted to find one closer to the boundary.
And there was a group of of avocation
or fossil hunters who have a company that
digs up and sells fossils of paleo prospectors
Steve Nicholas and Rob Silva.
They originally set foot on the site
and they saw all these fish poking out of the site,
which was a big red flag for them.
You don't see fish
in the Hell Creek formation before that site.
There were, I think, three or four articulated fish.
It doesn't happen.
The preservation bias is against
the preservation of fish like that.
So that was exceptional.
Oh, my God, we've got fish at the site.
And little did we know that we'd be,
you know, wowing over everything else later.
But that point, it was the fish and they thought it was a lake
at first because of the striations.
And that was interesting to me.
And they facilitated the work to move forward to
my research group.
And that's the best thing that could ever have happened
because we were able to piece together
everything that occurred thus far in our research
and we were able to get all of these specimens, preserve them,
because the environment out
there is not conducive to the preservation of fossils.
They're imperiled every moment they're in the outcrop,
they will get washed away. The winter is bad on them.
So that whole situation ended up
culminating in a tremendous research project
and an amazing interpretation of the site and data
that is now able to be used by God knows how many people
to try to put the story together.
So yeah, that one group actually first set foot on the site,
and if they hadn't done that,
who knows if it ever would have been found?
Because there were other people, researchers
working in that area for decades and they never saw the site.
They never even found it.
No, they knew you like fish.
And so they were like, Hey, there's something cool.
Just look at this fish and and look what history made for us.
You know, it goes from fish to putting together little, tiny
details of this massive story of the end of the Cretaceous.
Who would guess you're talking about the data and all that?
I mean I mean, you guys are all here also.
I mean, collaborate.
I mean,
what would you like to get from this group
and what would you like to get from NASA
that will make, you know, things even better?
The story even more interesting,
making you guys think here at NASA,
the stuff you really like to get a hold of the years.
I mean, not, not physically, but I mean, we, we just.
We discussed, um, just earlier, you know,
what else is in those? Right.
I mean, if there are air inclusions
that can give us hints of what that paleo atmosphere
was like in terms of carbon dioxide levels, methane levels.
I, you know, it it's I mean, like, just like in
an ice core, you know, we preserve these bubbles,
you know, that go back a million years.
Okay.
This is this is another this is another level, of course.
But but if if there if there is air that can be analyzed,
that's that would be that would be a huge a huge
input into what we're doing,
because we know that, you know, at that period.
Right.
You know, the kind of end Cretaceous time
climate was changing even before the impact happened,
that there were there were climate changes. And
and, you know, this is a long period.
There's lots of other things that happened in the Cretaceous,
the ocean, anoxic events and,
you know, the peak Cretaceous times.
But there were things happening
right then that that we don't really understand.
You know, it was it was it related to tectonic changes,
you know, closures of various seaways, the sea in Europe?
You know, it's very it's unclear.
And so there's a lot of focus on
what was happening immediately before the impact.
But then to have, you know, like examples
that could really kind of ground
truth, some of those speculations
would be of enormous interest.
And then you have the the things that could evaluate
how well our simulations are working, right?
So, you know, so we put in these assumptions,
we run
these models of various kinds, and you'd have to string them
all together, you know, kind of one after the other.
And then, you know, okay, well, we predict
this may have happened
all this tell us from the data which one it was.
Right. And then we can kind of constrain things coming back.
And so so those kinds of things like,
you know, things like temperature is things like
know water isotopes or you know, all sorts of,
you know, the,
you know, how much burning there was, how much
how much charcoal you find.
Those are the kinds of things that are
that are really key for evaluating
our kind of suppositions of more than that.
Right?
I mean, you don't have all of the little bits of amber
that you're going to find these things that that site has.
We've only seen the tip of the iceberg,
only the tip of the iceberg every single season
that we go out there and that the other research
groups from other universities join us out there.
Something is found that we've never seen before
and it carries the research forward.
And we were just having a conversation
before about nondestructive analysis.
I can think of a whole host of things that would be amazing
for collaborative work, on the nondestructive analysis,
on the ejecta and the other items here.
That would be they would offer volumes of data.
And with the hydro modeling in terms of of better
modeling of the of the dynamics of the surge wave,
that's something that is an amazing project
that could probably lead to multiple papers,
you know, down the road.
And I think there's another aspect,
which is Roberts already talked about it,
which is,
you know, this is one cosmic event recorded in Earth history
with all the climate and other implications.
But there's others.
I mean, recently the Hiawatha structure in Greenland was
identified as being relevant to this
transitional period of time,
you know, into the PG, the paleo gene.
We have others where there were mass
extinctions observed of different magnitude.
The Oligocene that puppy guy the promote Triassic further back.
These are the Earth record as the chronology
of the solar system that we use relative to the moon
and other chronometers.
This is critical for planetary sciences.
So I think Robert's
data and materials
can be analyzed through some of those techniques
he mentioned,
which we're now using on lunar rocks,
some of which have been, you know, stored away for 50 years.
So we have the better tools so that cross,
you know, cross-disciplinary
collaboration, I think would be very fertile.
And I have a question for you which relates to that,
which is so what about the pollen?
You've now got Amber, you've got zeros,
you've got pieces of the impacting object.
Then there's pollen,
which is a very good indicator of many aspects of environment
and really robust one in the earth history
you've talked about a little bit,
but maybe that's an area of very exciting
sample analysis and it's underexplored right now
too, because the pollen so far,
yes, it exists at the site, beautifully preserved.
And thus far it has been explored
mainly as a bio stratigraphic marker.
So we're establishing where we are in time.
But in terms of working out the biota back then
and the the turnover of the ecological turnover
and what happened
right at that moment and then up into the lower
paleo gene that has been done over
there yet and it is ripe for the study.
So I was going to ask before, when
do you want to get started? But.
You know, with the pollen, too, I think
we're already in the danger.
So I'm ruminating on
this is like the archetype of hands on research.
Quack, quack, quack
with your tools and dig
in a little bit into the rock and see what you find.
And then
if you're lucky,
you notice that there's
this little brown layer and you realize it's
a dinosaur skin and you're really super careful.
But I keep thinking,
isn't there something high tech engineering could give you?
And I don't know what you need, but I sure think
it's worth finding it, whatever it is,
because this is so important and it's so precious
and there's no other site like this
in the entire planet that we know of.
So we need to get everything we can.
And so before it all washes away,
let's find it and
let's give you all the help we can possibly imagine.
I'll never try to turn away any
really, really, really good recommendations on that end.
And putting
on the thinking caps, because you're absolutely right,
with the fossils and their mode of preservation, they're there.
They're very fragile.
They're they're almost impossible to prepare
and to stabilize.
We have had to develop
new techniques and excavation and stabilization for these
that are different than what you normally use.
And they'll creek formation.
They dictate that we have to do that.
And basically through that process
we have developed incredibly,
painfully detailed excavation practices
going centimeter by centimeter and then stabilizing as we go
to accomplish this.
But we're
always trying to up our game
and we are always trying
to refine these methods and find better methods
and really think outside the box.
We recently
got some of the specimens that were almost impossible to move
because you put plaster jackets on the matrix.
But if that is saturated with moisture, you can't move it.
It's going to be basically the consistency of peanut butter.
It'll it'll get destroyed. So what do we do?
You can't put glue on that because the glue is not going
to go. It's already saturated with something else.
So we decided, okay, we'll use whatever it's saturated in,
which is water to then stabilize it.
So we flash froze this block with liquid nitrogen,
turned it into a solid block,
stabilized it that way, moved it out.
And then we thought it in a controlled environment
before research
and we determined via SDM analysis and the
thin sections that that was not harmful to the fossil.
So we need a lot more,
a lot more thinking outside the box like that
and it's not just going to come from us.
So you are liquid nitrogen factory on site.
I was thinking about you and I get liquid nitrogen.
We got liquid nitrogen.
We know how to do that.
I was actually thinking about
I can work on stabilizing organic compounds,
which is useful in the Mars analysis.
I mean, in that case, you're basically going
molecule by molecule to stabilize the sample.
That's something people do here
that would be absolutely useful.
Absolutely.
Also, the new classes of topographic
imaging at outcrop scale that are now being used
in certain sectors,
including in geophysical exploration,
could image at centimeter scale in a three dimensional volume
into a target depending on wavelength.
So that could characterize
your site before you've actually dug into it.
The biology group, I think, needs to be very helpful.
Yeah, absolutely.
It was speaking of astrobiology and stuff
in the search for life outside.
So I mean,
understanding impacts like this here,
how does that help us understand other planets better?
I know that's something you think a lot about.
Well, I'm just struck because on Mars and Venus, we have two
excellent class impacts in the more and more recent
eras of their record.
And we use those on the moon to characterize all time blocks.
We see them on Mars.
We wonder about them in this, you know, more recent history,
historical period of Mars
as not something from Gale
Crater three and a half billion years ago,
but something from the last billion.
And then there's Venus, where there's only one in this size
class, maybe two if you get sketchy.
So, wow, what did Venus did, as some climate models suggest
done, in fact, at Gavin's group have persistent surface
waters for billions of years
and that suppressed the record of impact.
And the only ones we see
are those that happened later that are more recent,
that are the sixth lives of Venus or other worlds.
And I just thinking of Mars and Venus
because they're climate relevant objects nearby and exoplanets
where John's telescope and others will be able to start
ferreting out those classes of objects.
You know, they might have reflected
an impact preserved aspect of atmospheric change.
Unbelievable the connections.
And so we need Earth Ground Truth
to apply that message forward.
And you've done that.
And I think we can learn from you
and we can continue doing it forward. Right?
Right, right.
Yeah. Not just me.
It's a massive, massive collaboration.
Lots of women, men working on this is all good.
I think we've got a plan going forward and I guess emails
want to say thing before we wrap up our discussion.
When can we visit?
One incredible day. That's right.
Well, we'll start making plans.
It's mushy right now.
And that's the technical term. Right.
But. But.
The sky's the limit.
Let me know when that will wrap it up.
Thank you so much for joining
this exciting day here at NASA's Goddard Space Flight Center.
Thank you very much. Thank you.