Tanis: 'First dinosaur fossil linked to asteroid strike'
April 6, 2022 6:29 PM   Subscribe

Scientists have presented a stunningly preserved leg of a dinosaur. The limb, complete with skin, is just one of a series of remarkable finds emerging from the Tanis fossil site in the US State of North Dakota. But it's not just their exquisite condition that's turning heads - it's what these ancient specimens purport to represent. The claim is the Tanis creatures were killed and entombed on the actual day a giant asteroid struck Earth.
posted by Etrigan (29 comments total) 43 users marked this as a favorite
 
Exciting! It's remarkable how recently the asteroid impact theory became settled science. (T. Rex and the Crater of Doom was a great read.)
posted by Monochrome at 6:32 PM on April 6, 2022 [3 favorites]


Um wow!
posted by supermedusa at 6:53 PM on April 6, 2022 [2 favorites]


The Tanis site sounds f#$%in wild! I remember hearing about it a couple years ago, maybe on a Radiolab episode? The idea of finding fossils and stuff from the very moment of the Chicxulub impact is so cool. I vaguely recall there was some skepticism about stuff being published in the popular press ahead of peer reviewed research, so I'm glad that more thorough work appears to be ongoing.
posted by Wretch729 at 7:00 PM on April 6, 2022 [4 favorites]


Thanks very much for this, Etrigan: I've been going back and forth on posting about this since I first heard related news on an episode of Paleocast.

To me, the most surprising and fascinating fact to come out of the most recent digs at Tanis is that the impact, some 66 million years ago, likely occurred during the spring, as detailed in the article. How? Some of the fishes at Tanis have tiny spheres of molten rock trapped in their gills. These spheres were some of the first ejecta from the impact: landing in water after being thrown north, they were inhaled by paddlefish that inhabited the area before a slower-moving lahar from the asteroid impact entombed them forever. By looking at the growth rings in the fish's tiny fossilised bones using a particle accelerator, they found that the animals had just started their spring growth stage.

(Nature paper by Melanie During and her co-authors on the finding.)

Ironically, this doesn't increase the accuracy of the impact’s date, which remains approximately 66,036,000 BCE ± 11,000 years, due to current limitations in argon-argon dating. But there are a bunch of really interesting suppositions that lead from it, including the possibility that species recovery radiated from the southern part of the Earth: animals in the wintery south were more probably hibernating, and thus more likely to survive the immediate effects of the impact.
posted by Bora Horza Gobuchul at 7:19 PM on April 6, 2022 [29 favorites]


It’s like a Gary Larson cartoon made (fossilized) flesh.
posted by ricochet biscuit at 7:52 PM on April 6, 2022 [4 favorites]


Here's a recent episode of SciShow talking about the evidence for a northern-hemisphere Spring impact.

It is utterly astounding to think that we can identify from fossils of animals that they died on a specific day 66 million years ago. It's a hell of a thing.
posted by biogeo at 8:29 PM on April 6, 2022 [5 favorites]


This is so interesting! Fossils with inhaled spherules from the Chixiculub impact!
posted by Oyéah at 9:21 PM on April 6, 2022 [1 favorite]


It's fascinating but it's hard not to feel pity for those terrible choking deaths. Or the ones who starved after. Dinosaurs were here such an incredibly long time, so much longer than we've been around. And then one giant space rock later, poof.
posted by emjaybee at 9:58 PM on April 6, 2022 [9 favorites]


To me, the most surprising and fascinating fact to come out of the most recent digs at Tanis is that the impact, some 66 million years ago, likely occurred during the spring, as detailed in the article ...

April could indeed be the cruelest month.

Of the last 66 million years.
posted by jamjam at 10:12 PM on April 6, 2022 [5 favorites]


Without any basis for evaluating the science whatsoever, I'm wary of the "we found fossils from this exact day 66 million years ago," even if it was a day of such epochal significance. People love to find a tomb and decide it's Jesus's tomb, find an inscription referencing a Roman army officer in Dalmatia named Arthur and decide it's King Arthur, find a portrait of an Elizabethan dude with a high forehead and decide it's Shakespeare, etc.
posted by sy at 12:05 AM on April 7, 2022 [2 favorites]


Tanis, you say? Maybe they'll find the ark of the covenant, too.
posted by dowcrag at 12:25 AM on April 7, 2022 [7 favorites]


...find a grave in a car park and decide it's Richard III...

Sure, skepticism is good and necessary, but sometimes the thing is the thing. If you find fossils of fish that had inhaled tiny glass spherules containing bits of asteroid, that's some pretty powerful evidence. The fossil turtle skewered by a wooden stake, too (alternative hypothesis: evidence of Cretaceous vampire-turtle hunters).
posted by rory at 1:02 AM on April 7, 2022 [19 favorites]


My skepticism comes from De Palma's involvement in this. Read the New Yorker article. Excerpts include:
One prominent West Coast paleontologist who is an authority on the KT event told me, “I’m suspicious of the findings. They’ve been presented at meetings in various ways with various associated extraordinary claims. He could have stumbled on something amazing, but he has a reputation for making a lot out of a little.” As an example, he brought up DePalma’s paper on Dakotaraptor, which he described as “bones he basically collected, all in one area, some of which were part of a dinosaur, some of which were part of a turtle, and he put it all together as a skeleton of one animal.” He also objected to what he felt was excessive secrecy surrounding the Tanis site, which has made it hard for outside scientists to evaluate DePalma’s claims.
And now with an upcoming BBC special? Thats definitely an arena where Science succumbs to showmanship.

The Nature article by Melanie During et al. is the real deal but thats not what this is about. This is about a dinosaur leg not some boring fish spherules. In any case, why isn't De Palma a co-author on the fish spherules paper? The only mention he gets is a very curt sentence in the acknowledgements "We thank R. DePalma for providing guidance in the field and access to the specimens. "
posted by vacapinta at 1:38 AM on April 7, 2022 [8 favorites]


+1 t-rex and the crater of doom. authored by the younger alvarez, the geologist and originator of the theory. for popular readership.

i think with plate tectonics, this is the largest scientific revolution in my lifetime.

uncanny how shoemaker-levy 9 set the stage for wider acceptance of the theory.

plus you learn about spherules.

the k/t boundary sample (under glass) is my favorite exhibit at the denver museum of nature and science. i think i have never not run my hand over it awe and wonder.
posted by j_curiouser at 3:55 AM on April 7, 2022 [4 favorites]


the New Yorker article

Previously.
posted by zamboni at 5:27 AM on April 7, 2022 [1 favorite]


It was in the spring
I think the month of May
When The Big Rock hit
And blew them all away.

Now they're gone
And I don't worry
The Rock put me
In charge of the World.

--Doc Feelgood & his short-string band
posted by mule98J at 7:49 AM on April 7, 2022 [1 favorite]


I'd assume the reason DePalma wasn't an author on the paper about the spherules in the fish gills is that he wasn't involved in the work beyond what they acknowledged him for. And an acknowledgement of that sort is pretty typical for someone's who's provided valuable assistance but didn't contribute as an author (i.e., providing intellectual input). I wouldn't really make anything of it at all.

All scientific knowledge is provisional, and it's quite right to approach a claim like this with skepticism. For a long time, the idea that the K-Pg extinction event was caused by an asteroid impact was also regarded as an extraordinary claim meriting a lot of skepticism, and rightly so. Scientific knowledge, provisional as it is, requires multiple lines of evidence from multiple independent researchers to be accepted. But it does seem that there is a community of researchers who are convinced by at least the basic claims that this fossil deposit includes specimens that were deposited on the day of the Chicxulub impact, and some of that evidence seems to be independent of DePalma's work. I certainly wouldn't rule out that there is overenthusiastic interpretation, overselling, or outright fraud involved here, but the body of evidence laid forth so far seems reasonably compelling to a nonspecialist like myself, and has apparently been convincing to at least a reasonable fraction of their scientific peers so far. Time will tell if the story holds up to further evidence. For now, I'm prepared to provisionally accept it.
posted by biogeo at 10:04 AM on April 7, 2022 [3 favorites]


I want to believe. I do have some questions about a person who has been working a gold mine of a site like this for at least a decade but has been a graduate student the whole time, and is conducting publication by press release. But the New Yorker article suggests that De Palma’s advisor at Kansas died, and the BBC article gives him a UK academic affiliation. The timing is right for the New Yorker article to have attracted healthy academic supervision from U.Manchester, but with funding from the BBC’s documentary arm.

Tons of these BBC nature documentaries have lines like “this next phenomenon has never before been captured on film,” which suggests to me that they have not just a research staff but connections with working, creative academics. If I were in an academic discipline that got clarity from high-quality photography, an arrangement where I could direct professional cinematographers at my research subject, funded by them eventually selling a documentary about my work — there are a lot of ways an arrangement like that could go right.
posted by fantabulous timewaster at 10:26 AM on April 7, 2022 [1 favorite]


evidence of Cretaceous vampire-turtle hunters

And maybe some sort of turtle-android Highlander-like scenario might be involved. We will never know until nexflix buys the first season.
posted by NoThisIsPatrick at 10:47 AM on April 7, 2022 [2 favorites]


And now with an upcoming BBC special? Thats definitely an arena where Science succumbs to showmanship.

Did anyone else clock the hat DePalma was wearing? That's a guy cultivating an image as a Dinosaur Hunter™.

Which I love for him, by the way. I also hope this is true and if a person dressed like Indiana Jones made the discovery, all the better.
posted by GalaxieFiveHundred at 12:25 PM on April 7, 2022


It implies the direction of the asteroid impact, or could. If enough fossils were blown in one direction, and the spherules were largely one sided, even in a small area.

If you came this way, starting from any route, at any time or season...
posted by Oyéah at 12:34 PM on April 7, 2022


When you get up in the mornin' and you see that crazy sun
Keep me in your heart for a while
There's a train leavin' nightly called "When All is Said and Done"
Keep me in your heart for a while
- Warren Zevon
posted by thecincinnatikid at 12:35 PM on April 7, 2022 [2 favorites]




It implies the direction of the asteroid impact, or could.
Actually, not really. The debris cloud has the same momentum as the ejected material. For impacts above a certain size, most of the ejecta comes from the planet, rather than from the impactor. Consider that the Chicxulub impactor was about six miles across, but the crater is a hundred miles across and between ten and twenty miles deep. Nearly all of the ejecta are released from the rest frame of the planet's surface.

For other examples, look at craters on the Moon and on Mars. There are essentially no vertical impacts, but essentially all of the craters are circular. If you dig hard enough through your astronomy textbook you can find a very few examples of asymmetric craters caused by grazing collisions.
posted by fantabulous timewaster at 1:56 PM on April 7, 2022 [4 favorites]


I missed this post somehow! Had to come across one of the articles elsewhere and then come to see if I needed to post. I'm really looking forward to seeing the special.
posted by tavella at 9:11 AM on April 12, 2022 [1 favorite]


Just watched the special. It's very compelling. Lots of scenes where we get to watch them unearthing fossils, spherules, the lot. If Tanis isn't a site from the last day of the Cretaceous then it needs a lot more explanation of what else it could be than "Depalma hasn't finished his PhD yet". If I were excavating the most exciting paleontological site imaginable, I'd find it hard to tear myself away to finish the thing too.
posted by rory at 4:03 PM on April 20, 2022 [1 favorite]


Yeah, they literally dig a fish out of the mudstone and crack the head open and show the spherules. They filmed them digging the dinosaur leg out. It's really hard to see how it can be anything but exactly what it appears. I can understand other scientists being driven mad by only a handful of papers having been published, and unthrilled by the fact that everything is in private control rather than a public museum, but most of the criticism seems very personal and petty.

Also what the hell was it with the "location closely guarded" and then all the drone landscapes zooming in on the site? I'm pretty sure the geolocators of the world had it identified within half a minute. Hope they don't turn up next digging season and find it bulldozed.
posted by tavella at 4:47 PM on April 20, 2022 [1 favorite]


I guess the one thing that isn't settled is that I don't think the chemical match for the tektites has been verified by an independent group, since the blocks the Field Museum had from the original excavation didn't have any. But they have the fossil of a Thescelosaurus, which only appears at the very end of the Cretaceous, so you'd have to have had a previously undetected meteor strike that was big enough to leave huge numbers of tektites within a couple of million years of the K-Pg boundary. And they actually show the K-Pg boundary stripe in the documentary, I believe, as at the top of their site. Parsimony suggests it is what it looks like.

I do hope they start publishing more. There's all sorts of fascinating mentions, such as the famous mammal burrow that actually goes across the KT boundary, feathers, ant nests filled with tektites, I certainly sympathize with the exasperation of many scientists. But not the "well, he misidentified a turtle bone once, so DePalma must be a bad scientist." I've seen enough embarrassed re-writing of scientific literature where a skull got put on the wrong way or a species didn't actually exist, it was a bad reconstruction of an already identified one, etc, to know he's hardly the only one that happens to.
posted by tavella at 2:51 PM on April 21, 2022 [1 favorite]


I'm also wondering about the claim that the sun was blocked out for a decade. I'm having trouble believing any larger land animals would have survived that, and apparently some up to 25kg did. There would have been seeds, and a lot of insects the first year or so from all the corpses, but surely that wouldn't have lasted 10 years?
posted by tavella at 9:55 AM on April 22, 2022


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