# The KT impact: deaths on the day found in Dakota **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [March 30, 2019, 9:47am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757 "2019-03-30T09:47:37Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 1, 2019, 5:07pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/61 "2019-04-01T17:07:50Z")
> [@Colibri](#): > > Any scientist I know would be ecstatic to have a paper accepted by PNAS. To be fair, yelling out that you have been accepted by _Science_ or _Nature_ is much less likely to lead to an embarrising misunderstanding. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 1, 2019, 5:20pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/62 "2019-04-01T17:20:01Z")
> [@wolfpup](#): > > The irony of it all is that both articles that **Darren Garrison** cited are breathlessly sensational and completely uncritical endorsements of the paper, gushing about what a fantastic discovery this is, while the _New Yorker_ article is the only one that quotes independent researchers calling for more study and healthy skepticism, along with providing a lot more scientifically pertinent background. Here’s[_National Geographic’s_ article on it](https://www.nationalgeographic.com/science/2019/03/fossils-found-from-day-dinosaurs-died-chicxulub-tanis-cretaceous-extinction/), which also mentions criticism. However, the criticism seems to come mostly from people who have not seen the site or the article, rather than those who have. ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [April 1, 2019, 5:46pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/63 "2019-04-01T17:46:44Z")
> [@Colibri](#): > > You really, really, really, really should just stop digging. But it’s about palaeontology ! Digging is _de rigeur_! ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 1, 2019, 5:48pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/64 "2019-04-01T17:48:35Z")
> [@Darren\_Garrison](#): > > That is [the second comment](http://www.thefossilforum.com/index.php?/topic/93793-dinosaur-killing-asteroid-mark-on-north-dakota/&do=findComment&comment=1034342) I’ve seen saying that the paper is only about the triceratops bone. Certainly, that comment is wrong. It says: > [@](#): > > Obviously, this will change shortly but my understanding is that the upcoming paper only really covers the Triceratops ilium. The misconception seems to be based on the fact that only one dinosaur bone is cited in the PNAS article. From National Geographic: > [@](#): > > According to the New Yorker, Tanis abounds with fossils, including teeth, bones, and hatchling remains of almost every dinosaur group known from the Hell Creek Formation. The story also reports the presence of foot-long feathers possibly from dinosaurs, pterosaur remains, and an unhatched egg of some kind with a preserved embryo inside. > > None of these details are in the study, however. No dinosaur bones are mentioned in the main study, and the supplement highlights only one hip-bone fragment from a horned dinosaur like Triceratops, found with “associated impressions of tissue.” (The New Yorker claims that a suitcase-size piece of fossilized skin is attached to the bone fragment.) On the other hand, if that is correct, then UC Berkeley and the Science Daily article based on it also include details not found in the PNAS article: > [@](#): > > This is the richest K-T boundary site ever found, incorporating insects, fish, mammals, dinosaurs and plants living at the end of the Cretaceous, mixed with tektites and rock created and scattered by the impact. The find shows that dinosaurs survived until the impact. Note “dinosaurs” is plural. > [@](#): > > Smit [one of the co-authors] also noted that the buried body of a Triceratops and a duck-billed hadrosaur proves beyond a doubt that dinosaurs were still alive at the time of the impact. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 1, 2019, 5:49pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/65 "2019-04-01T17:49:34Z")
> [@Northern\_Piper](#): > > But it’s about palaeontology ! Digging is _de rigeur_! He hit bedrock quite a while back. 🙂 ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [April 1, 2019, 6:02pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/66 "2019-04-01T18:02:42Z")
> [@Colibri](#): > > He hit bedrock quite a while back. 🙂 No need to stop there: 🙂 “Keep straight on… give my regards to the earth’s core!” \*-- Basil Fawlty, “Communication Problems”, \*Fawlty Towers ---
**Author:** ![GargoyleWB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gargoylewb/32/199_2.png) [@GargoyleWB](https://boards.straightdope.com/u/GargoyleWB)\ **Post date:** [April 1, 2019, 6:54pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/67 "2019-04-01T18:54:31Z")
> [@Kimstu](#): > > … > Calling the non-technical parts of the article “fluff” just comes across as a form of bragging that you are already familiar with some of the technical background… I disliked the New Yorker ‘fluff’ also, but for more of an editorial reason. The content was in depth and superb, so kudos are warranted especially to the author for communicating so much dense info to a general reader was well done. What I disliked was the constant hopscotching all over in time between present, past, data, past, data, present…it felt more to me, as a reader, like essay padding to reach a word count rather than substance. For fascinating bits, I loved the description of the fragility of the specimens and the careful steps needed to try and preserve them for removal. It makes me wonder how many great discoveries simply crumble to dust unawares. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 1, 2019, 7:33pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/68 "2019-04-01T19:33:51Z")
[The full paper is now available](https://www.pnas.org/content/early/2019/03/27/1817407116). ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [April 1, 2019, 7:46pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/69 "2019-04-01T19:46:30Z")
> [@Darren\_Garrison](#): > > [The full paper is now available](https://www.pnas.org/content/early/2019/03/27/1817407116). Thank you. It must have been released just minutes ago. I had been checking all day and had that exact link to the paper on the PNAS site, but was getting “access denied” all day until just now. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 1, 2019, 8:24pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/70 "2019-04-01T20:24:52Z")
> [@Darren\_Garrison](#): > > To me, the most interesting thing in the _New Yorker_ article is [this photo](https://media.newyorker.com/photos/5c9d2658dec8304049bc4de1/master/w_1548,c_limit/190408_r34054.jpg)–the tektite at the bottom (too big to be a “micro” tektite) has punched through a number of [varves](https://en.wikipedia.org/wiki/Varve), distorting the edges, and left a conical crater at the surface (with the “surface” halfway down the specimen) that was infilled with light colored sediment. Below the tektite the sediment is compressed downwards in a lens shape, and the fact that the tektite is off-center of the area of damage _may_ indicate the angle that it was traveling as it fell. There is a clearer photo of this specimen in the full paper that is even more suggestive of an angled trajectory for the tektite. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 1, 2019, 8:53pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/71 "2019-04-01T20:53:32Z")
> [@Darren\_Garrison](#): > > [The full paper is now available](https://www.pnas.org/content/early/2019/03/27/1817407116). > [@wolfpup](#): > > Thank you. It must have been released just minutes ago. I had been checking all day and had that exact link to the paper on the PNAS site, but was getting “access denied” all day until just now. I just finished reading it. It’s clear that this paper is focused on documenting the most significant aspect of the site, that it was a deposit laid down within minutes or hours of the asteroid impact. There’s no attempt to analyze the fauna or flora in detail, except to document that it includes both marine and terrestrial species. The mention of the dinosaur bone in the appendix is in the context of saying it was not killed in the event but was from a dead individual and floated there. There is no mention of mammal burrows or other dinosaurs. But that’s fine, because that’s not the focus of this paper. Now the fact that the deposit may contain dinosaur remains and mammal burrows is cool, but it’s not the outstanding scientific finding of the paper. People who are complaining that it’s just about “a bunch of fish,” and doesn’t describe heaps of dead dinosaurs are idiots. ---
**Author:** ![asahi](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asahi/32/8693_2.png) [@asahi](https://boards.straightdope.com/u/asahi)\ **Post date:** [April 1, 2019, 9:06pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/72 "2019-04-01T21:06:50Z")
It’s indeed a fascinating find, though I don’t know if the title of the New Yorker’s article is quite accurate. The meteor impact in the Gulf of Mexico almost certainly contributed to the demise of dinosaurs, but I’ve read that there’s a growing body of evidence suggesting that volcanic activity - from where else, the Deccan Traps - probably contributed as well. [https://www.nationalgeographic.com/science/2019/02/what-actually-killed-dinosaurs-volcanoes-heat-up-debate/](https://www.nationalgeographic.com/science/2019/02/what-actually-killed-dinosaurs-volcanoes-heat-up-debate/) ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 1, 2019, 10:01pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/73 "2019-04-01T22:01:18Z")
> [@asahi](#): > > It’s indeed a fascinating find, though I don’t know if the title of the New Yorker’s article is quite accurate. The meteor impact in the Gulf of Mexico almost certainly contributed to the demise of dinosaurs, but I’ve read that there’s a growing body of evidence suggesting that volcanic activity - from where else, the Deccan Traps - probably contributed as well. > > [Volcanoes probably helped kill the dinosaurs. But scientists don’t agree how.](https://www.nationalgeographic.com/science/2019/02/what-actually-killed-dinosaurs-volcanoes-heat-up-debate/) That controversy has been running for decades. As the article says, the eruptions are thought to have played a supporting role, but not to have been decisive in the extinctions. And even those two studies cited differ in their conclusions, with one dating the peak eruptions to after the KT event. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 1, 2019, 11:29pm UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/74 "2019-04-01T23:29:58Z")
Something that has been bugging me about this is the terminal velocity of the microtektites–it seemed odd that they could be travelling fast enough to penetrate the mud like that. I did a quick and dirty [calculation](http://www.calctool.org/CALC/eng/aerospace/terminal) using 3 mm for the diameter of the penetrator (per the article) and the [density of window glass](https://www.aqua-calc.com/page/density-table) (good enough for a rough figure) and I get a 3 mm spherical tektite with a terminal velocity of around 60 miles per hour. So, 1/10th or less the muzzle velocity of a bullet, 1/4 the muzzle velocity of a slow BB (or about 3x the speed of a fast raindrop.) ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 3, 2019, 2:29am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/75 "2019-04-03T02:29:49Z")
[A new article](https://www.news.com.au/technology/science/archaeology/something-is-weird-the-incredible-dinosaur-graveyard-that-is-raising-eyebrows-in-the-palaeontology-world/news-story/52555bb53223cc14435f1bf3c178a83f). ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 3, 2019, 3:07am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/76 "2019-04-03T03:07:01Z")
> [@Darren\_Garrison](#): > > [A new article](https://www.news.com.au/technology/science/archaeology/something-is-weird-the-incredible-dinosaur-graveyard-that-is-raising-eyebrows-in-the-palaeontology-world/news-story/52555bb53223cc14435f1bf3c178a83f). Another idiot take on the paper. As I said, the point of the PNAS paper was to document that the site was from immediately after the asteroid impact. Complaining how the paper doesn’t contain everything mentioned in the New Yorker article is moronic. The New Yorker article makes a big deal of the “3 meter gap” of dinosaur remains below the KT boundary, but [some scientists question such a gap occurs at all.](https://ecee.colorado.edu/~ecen5009/Resources/Dinosaur/Sheehan2000.pdf) And in 2011, [a ceratopsian horn was found with 13 cm of the boundary.](https://earthsky.org/earth/scientists-find-evidence-of-dinosaurs-just-before-extinction) Aside from a few advocates of the volcanism hypothesis who have a special case to plead, most paleontologists believe dinosaurs were present up to the KT event. While the fact that there were a variety of dinosaur remains found at Tanis is cool, it is not nearly the most significant aspect of the site. In any case, it was necessary to establish that Tanis actually represents the KT boundary _before_ the fact that dinosaur remains were found there take on significance. ---
**Author:** ![GreenWyvern](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/greenwyvern/32/2834_2.png) [@GreenWyvern](https://boards.straightdope.com/u/GreenWyvern)\ **Post date:** [April 3, 2019, 7:23am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/77 "2019-04-03T07:23:35Z")
Note that this is just the initial paper. It was received for review in October 2018, and was probably being written for a couple of months before that. In due course we will get feedback from the experts about it. A lot more work has been done since then, and there will be many more papers to come. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [April 3, 2019, 9:40am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/78 "2019-04-03T09:40:04Z")
[Link to DePalma’s actual paper, “A seismically induced onshore surge deposit at the KPg boundary, North Dakota”](https://www.pnas.org/content/early/2019/03/27/1817407116) ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [April 3, 2019, 11:20am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/79 "2019-04-03T11:20:50Z")
> [@Darren\_Garrison](#): > > [The full paper is now available](https://www.pnas.org/content/early/2019/03/27/1817407116). Thank you; commence the big PNAS jokes. But always DOI please so we have a permalink: 10.1073/pnas.1817407116 I wish their embargo rules were stronger so we didn’t have to suffer so much fluff “science journalism” prior to the paper coming out. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 3, 2019, 11:30am UTC](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757/80 "2019-04-03T11:30:12Z")
(Damnit, Jim) I’m a physicist, not a paleontologist, but I’d expect a find of this magnitude to generate many papers for its discoverers, even before we get into the flurry of refutations, counter-refutations, verifications, and re-interpretations. Probably something like one paper for the site in general (what we’re getting now), and then a separate one for each individual relic. And it’s a touch hyperbolic to call this “the single most important day in the history of the Earth”. There have been other mass extinctions, some of them larger, and some of them also caused by asteroid impacts. [Previous page](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757.md?page=3) [Next page](https://boards.straightdope.com/t/the-kt-impact-deaths-on-the-day-found-in-dakota/831757.md?page=5)