Mass Extinction Causes that Nobody Talks About! (& Addressing Comments ;) | GEO GIRL

[@GEOGIRL]

Hey y'all! The first half of this video largely consists of me responding to comments from the first mass extinction causes video (kzbin.info/www/bejne/jaTWeJqImaZ7qMk) so I hope that I answered all your questions and queries from that video. If you do still have questions, though, please comment them below! I would love to continue our conversations from that video. You guys always bring such interesting ideas to the table, so thank you for that!! ;D

[@TheNativeTwo]

Why is global warming in the top 3 but global cooling / blocked sunlight is not? It is my understanding that more mass extinctions have happened due to global cooling and blocked sunlight than from global warming. Maybe global warming is more frequent cause for the largest of mass extinctions? Because for the smaller mass extinction events, the global cooling is the more likely mechanism, is it not?

[@albertvanlingen7590]

Next one will be a lack of C02

[@TheTumblingDice]

I agree with all this but the one thing that no one talks about is the repeating cataclysms that happen to our planet which appear in cycles on a distinct timeline which brings about the vapor canopy and then the collapse of that vapor canopy - this is talked about in 'myths'. I just wonder why these are not mentioned but yet we see evidence of this in older books. Everything makes sense and it all comes together when you factor this in.

[@Be_Harris]

Hello! I'm a old amatuer-level geology nut, and, on behalf of all we KZbinrs, thank you for promoting the academic perspective this subject deserves.

[@ramlan725]

Me too

[@MaryAnnNytowl]

You're one of the top science channels in quality, because you do the important work of leaving links to relevant studies, etc., in your description. Some of the "big guys" don't, and that's disappointing. You don't disappoint! ❤️❤️

[@Hellbender8574]

One of my favorite aspects of your channel is that you take the time to interact and respond to questions. Thank you for another great video.

[@barbaradurfee645]

I also love how so many of the viewers are willing to respectfully share their own scientific experieinces/ideas and engage in healthy back and forth. So much of Rachel's positive scientific etiquette reflects some remarkable mentors/professors at UT Arlington, UT El Paso, NASA, WHOI, and USGS (Golden/Denver) who set good examples. She's also just a super kid!!

[@GEOGIRL]

Thank you so much! I am so glad you notice and appreciate that ;D It's a lot of work but it is actually one of my favorite things about youtube is getting to interact with the viewers so much! I think it is so interesting to hear so many different perpectives that I don't ever hear from my in person students hahaha because they never speak up in class lol

[@GEOGIRL]

Oh stop @barbaradurfee, you're making it too obvious that you're my mom lol ;)

[@Hellbender8574]

​@@barbaradurfee645 Indeed, GeoGirl's must be one of the most civilized comment sections on KZbin.

[@josemariatrueba4568]

I wish she had the time, and the nerve, to answer why rapid changes in temperature from summer to winter or even faster from day to night that will go anywhere from very hit to very cold in a matter of six months or only 12 hours. Very much the same about the changes in co2 levels in a green forest or a small bedroom after two people slept with the window and the door closed that is not infamous 350 or 400 ppm growing in a matter of a few years, but from 100 to 1000 or even 10,000 ppm in a matter of 8 hours. Will she answer why rapid changes are The Problem? I don't think so.

[@oxon8871]

Just discovered your channel, and had an outsized emotional response to it. You see, I have just taken late (72) retirement, given my last exam, and am staring into a future unstructured by academia. Then I sit this lecture. In short, the future is, despite the grumblings you hear, in good hands; intelligence, diligence, imagination, discipline and curiosity are NOT in short supply. Thank you.

[@barbaradurfee645]

You are an inspiration 😊

[@GEOGIRL]

Thank you so much! I hope you are right about the future :)

[@GrannySmith]

I just love your videos Rachel, I’ve watched almost all of them, and a couple more than once. I think mass extinction events are crazy cool too. Would love a video on the Younger-Dryas & an explanation of the index proxy’s found in ice core samples, & the black matte layer..

[@GEOGIRL]

Thanks for the suggestion! I have a video about the holocene in general and in that I discuss the Younger Dryas a little bit, but I agree I definitely need to make a whole video just about the Younger Dryas! I will work on that! ;D

[@RobRoss]

Your videos have a level of detail that’s often over my head, not being a geologist. But still, I find them informative, fascinating, and entertaining. You have a great speaking style. Keep up the good work!!

[@GEOGIRL]

Thank you so much! I am so glad you still find them fascinating :D

[@Alberad08]

Thank you for providing another well understandable and vividly presented video about extinction causes - highly appreciated!

[@GEOGIRL]

Thanks! So glad you enjoyed it ;)

[@deepquake9]

You are really rocking it Geo Girl.

[@noitalfed]

Thanks! My graduate emphasis was biomedical imaging so I need two viewings to absorb even some of the information you put out there . Still as you say knowing the history of our planet is so cool and vital.

[@rabidwasp]

Thank you for an interesting, well presented and well researched presentation!

[@satoryvivseeker]

Interesting..

[@GEOGIRL]

Thank you! ;)

[@JCurcio]

Happy to find some videos that aren't at the like elementary school level of most climate videos/content for non-specialists, that is still fairly accessible to people with other academic backgrounds. Good stuff.

[@williamhastie2772]

Rachel supplying my weekly fix. 😬

[@GEOGIRL]

Thank you so much!! I am so glad you enjoy watching my videos ;D

[@reardensteele7841]

Only part way into this video - really good presentation. Lots of reference to animals. Any references to plants? Maybe I'm commenting too soon.

[@GEOGIRL]

Great point. Again, like I mentioned at the beginning of the video, we can only recognize official 'extinction events' in the fossil record when there are fossils in that record haha. So for species that do not preserve well (like soft-bodied animals or plants for example), the fossil record is very sparse making it difficult to determine degree of extinctions during these events for these species. Whereas, animals that have 'hard parts' (skeletons, shells, etc.) are preserved in the rocks much more often and thus provide us a more complete record, and that's why I talk more about them, there's just more information available on these types of organisms :)

[@matthewmorgan9269]

Excellent lecture ! Beautiful illustrations too

[@cavetroll666]

Just found the channel and love the content while working 🙃

[@GEOGIRL]

So glad you enjoy it! ;D

[@andresm.8838]

Fantastic explanation! Really like that you went back and clarified those details.

[@GEOGIRL]

Thanks so much! I am glad that I was behind in filming haha because it gave me a chance to go back and incorporate the response to those comments, which was super helpful for me as well because sometimes I forget to explain certain things or clarify things while lecturing :)

[@Geologize]

Wow, that was an awesome video! I just subscribed to your channel. By the way, as a geochemical paleoceanographer, I wanted to share with you that CO2 did indeed contribute heavily to mass extinctions, it was mainly through carbonic acid dissolution of carbonate skeletons (shells and coral). It's highly unlikely that animals were directly poisoned by CO2 entering their bloodstream. Anoxic conditions in the photic zone were rare. They mostly occurred in the ocean's oxygen minimum zone (OMZ), which expanded due to increased primary productivity from organic matter loading on the sea floor. This often disturbed the ocean's nutrient cycling, resulting in a positive feedback loop and runaway anoxia. However, it's important to note that the lack of oxygen, not excess CO2, caused many species to perish due to respiration failure. Hope this information helps!

[@GEOGIRL]

Oh my gosh! I am a geochemical paleoceanographer as well! What a small world! I am still a phd student, but my research is focused on refining paleoredox proxies, specifically molybdenum and thallium proxies. I specifically focus on reconstructions of ocean anoxic (and euxinic) events, so all this stuff you talk about in your comment I discussed in my "top 3 mass extinction causes" video (kzbin.info/www/bejne/jaTWeJqImaZ7qMk), which I would absolutely love to get your feedback on! Also, if there is anything else I missed or should look into, please let me know because it may make for a great future video, thanks! Also, I would love to hear about your research if you're willing to share :) Thanks again!

[@barbaradurfee645]

Great input thanks!!

[@williamhastie2772]

Mother earth is doing its best to kick us off the planet. Quite amazing that we’re around to discuss this between events. Great production Rachel.

[@GEOGIRL]

Thanks! I am quite glad we are still around to discuss these things as well ;) I think it's so cool that we can even learn so much about the past and how climates and environments have evolved through time! :D

[@NelsonDiscovery]

Keep trying, mother earth. I'm rooting for you lol

[@RonPaulgirls]

WHAT DO YOU THINK OF THE MASS INVASIONS INTO THE USA: 1. THE USA HIT BIO CAPACITY BY 1970 AT 200 MILLION 2. SINCE THEN WE'VE ADDED ANOTHER 150 MILLION OR WHATEVER 3 ALL MAINLY CAUSED FROM ILLEGAL AND LEGAL IMMIGRATION. 4. WHICH IS CAUSING A MASS DEGRADATION. 5. DISCUSSIONS OF OVERPOPULATION HAVE BEEN SUPPRESSED, CANCELED AND BOUGHT OFF, LITERALLLY. 6. POLITICAL MANUVERING TO ACCOMDATE THIS NIGHT MARE HAS BEEN FINANCED BY VARIOUS SPECIAL INTERESTS...THE PRIMARY MOTIVATIONS BEING, CHEAP LABOR, CHEAP VOTES...

[@brentwilbur]

"Mother Earth" is doing no such thing. Earth is a giant rock. A spectacularly beautiful, wet rock, but a rock nonetheless. It does not care about its lithospheric or atmospheric makeup, or the constitution or behavior of its surface dwellers. The idea that nature takes or should take revenge is just thinly-disguised misanthropy. _You_ do not like humanity so _you_ want to feel justified by saying Earth hates the same beings you do. That is sick.

[@Anuchan]

I wish we were a species that didn't work so hard to destroy our environment.

[@jessewilliams102]

I like how you’re using the earth to determine patterns of extinction level events. I don’t know if you’ve heard about it the ARCHAIX channel but he covers a lot of similar topics. I like his research because he doesn’t use any Internet sources. He just went through and data mined a bunch of old books that are no longer in circulation, except for the prison libraries where he found them. He talks a lot about cyclical cataclysms. I just came across your channel today and subscribed. Thanks for doing all that work.

[@nickbuffa1814]

It seems like you know everything to me! I’m amazed at how much you know and understand the things you talk about in your videos. I watch so many that someday I hope to understand like you do. It is all so interesting. Thank you 😊

[@JamesFitzgerald]

Yeah, she is all knowing. Amazing!

[@charlesjmouse]

As always, very good. Thank you. 'Cooling' vs 'warming' as a driver of mass extinction, thoughts to chew on for any interested: Techonomic - Maybe there is 'no' difference in severity or frequency, it's just an artefact of preservation? (is there any evidence?) Lethality - Maybe 'warming' and the associated mechanisms is worse for ecosystems than those for cooling? (my primary pick) Frequency - Maybe catastrophic warming has been far more common, especially in the Phanerozoic? Let's discuss as this doesn't come up much: If one considers the totality of life on this planet, it's pretty well founded that for most if not all of Earth's history this system has contained feedback mechanisms that act to keep temperatures in a comfortable range for the life present - let's be spooky and call that 'Ghia' for short. Over the roughly 4bn years 'Ghia' has existed the Sun has been slowly warning, I believe by about 20%. So much of a difference that if we consider today's environment to be pleasant science has been left with a bit of a conundrum as to exactly how the early Earth managed not to be a ball of ice. Horribly simplistically I would suggest beyond the early Earth's atmosphere being choc-full of greenhouse gasses it is 'Ghia' that has been moderating the temperature. In a little more detail: Early on 'Ghia' will have been 'adjusting' the global temperature up to 'compensate' for a cooler Sun - it's interesting that the 'snowball' events we know of are all to be found in the Precambrian. At some point as the Sun warmed an equilibrium point will have been reached, followed by a world where 'Ghia' has to increasingly act the 'adjust' the global temperature down - I would suggest this has been the case for most of the Phanerozoic and it's equally interesting that increasing temperature has been in some way associated with most of the known mass extinctions. What are we to make of this? If one considers the feedback mechanisms 'Ghia' has available either to adjust the global temperature up or down, all have their limits and most have a 'built in' inflection point where said mechanism starts to act against bringing temperature back to 'comfortable' there is a conclusion to be drawn when considering a warming Sun - one will find 'breakages' of moderating feedback by 'Ghia' will inevitably result in catastrophic cooling when the Sun is 'too cold' while catastrophic heating will be the result when the Sun becomes 'too hot'. This is pretty well the situation we seem to see in the geologic record. Predictions: -One might expect a trend catastrophic cooling events of becoming less common with time while catastrophic heating events increase in regularity - do we? -The point will come where the Sun becomes 'too hot' for 'Ghia' to cope with, I believe the current estimate is in about another 500million years, and our wet world will boil away. One would expect rather than witnessing a slowly heating world any descendants we my have will continue to enjoy much the same paradise as us but with an ever increasing frequency of mass extinctions associated with sudden global heating until a final episode arrives that doesn't end. Then our goose-descendant will be truly cooked.

[@nicholasmaude6906]

With the KT extinction event, Rachel, it was bad enough that the Chixulub impactor struck the sea (What was to become the Gulf of Mexico) as striking land would've done a LOT less global damage. But what made it worse is the geology of the impact site as it had a LOT of carbonate and sulphate bearing rocks so when the impact vaporised those rocks it pumped hundreds of billions of tons of carbon-dioxide and sulphur-dioxide into the atmosphere with the SO2 reacting with water-vapour in the air to form sulphuric-acid aerosols (In the areas around the impact site it was basically raining battery-acid). So initially it got very cold and after the sulphate aerosols had rained out it got very hot from the excess CO2.

[@nyoodmono4681]

It also alines with the 'indian traps' (In half of India the floor was lava), maybe even triggered by the impact itself. Btw did you see the huge amounts of SO2 that the Kamtchatka Shieveluch volcanoe released? The cloud is still there, moving around the whole planet.. quite impressive and way larger then from the recent canarian island eruption.

[@nicholasmaude6906]

@@nyoodmono4681 From what I understand the Deccan Trapps were already erupting when the Chixulub bolide smashed into the Earth so I suspect that the resulting seismic shock aggravated the eruptions.

[@jamesharmer9293]

A nearby gamma ray burst could really ruin your day. But what I've been wondering for the past year or so is, what's behind those two doors ?

[@GEOGIRL]

Hahaha the one on the right (my left) is the door to my room, so it's just a hallway behind there, and the one on the left (my right) is my bathroom ;)

[@jamesharmer9293]

@@GEOGIRL Thank you. Now I can sleep easy at night.

[@klauskarpfen9039]

07:45 So the end Cretaceous extinction event did not entail a cooling event? I was under the impression that the dinosaurs went extinct because of a global winter following the meteorite strike. I'd guess that global cooling is at least as much a major cause of mass extinction events as global warming

[@GEOGIRL]

There was an impact winter after the impact but the greater cause of extinctions over a longer time range was the warming that continued after the winter subsided from the dust settling. :) I have a video about the sequence of events following the KPg impact if you want to check it out! -> kzbin.info/www/bejne/q2OahJSErN2XZtk

[@christopherpett3264]

I believe you missed a major culprit for mass extinctions. That would be the depletion of ozone from sulfur dioxide from large igneous provinces in particular the Permian Triassic and the KT. Looking through numerous papers most overlook the effect sulfur dioxide has on the ozone layer. Peter Ward geologist and Professor Beers et al point this out in their research.

[@JSmith-ob6gh]

Hi- Dr. G.G, great job again. Thanks for the knowledge =) Dr. J

[@GEOGIRL]

Thanks! So glad you liked it ;)

[@JSmith-ob6gh]

Also, i was interested in that comet that hit the indian ocean approximately 5000 yrs ago I read about. The tsunami that followed really changed the global landscape in the surrounding areas with 100 plus meter waves i guess. Boy it makes you think of the Floods and story of Noah esp w the rain that followed. More of a cross thought lol. The sand chevrons that were formed are cool and interesting. So question...? The Sahara desert- how was that formed? Was it from a tsunami, wind, or something else?? Would you happen to know?

[@winycentaur2540]

Lovely video as always :), thank you!

[@tchahin]

I live precisely in Guarapuava, on top of Parana-Etendeka traps who had 9 of the largest volcanic eruptions according to scientific sources in Wikipedia list of largest volcanic eruptions.

[@Beastclub679]

Very nice video geo girl..✨✨... always love your videos 💖

[@vernowen2083]

Since retirement, I've done lots of research on major volcanic events, which I got interested in after surviving the Mount Saint Helens eruption. I have been surprised by the lack of research done on how volcanism affects our climate. I'm not talking about super volcanoes but the everyday major eruptions, such as Saint Helens. This led me to the impact, which supposedly wiped out the dinosaurs. I now say I have to agree with those that say the asteroid impact was not enough, but the concurrent basalt eruptions in India that tipped the scale, since the effects lasted for decades. I also believe the eruptions were triggered by the impact. Tell me what you think.

[@barbaradurfee645]

I had to pause and go off on a tangent to learn about fluorine fractionation in soil/ground water because you got me wondering about acid rain patterns showing up in the clays/soil etc, etc, anyway fun video, thanks!!

[@barbaradurfee645]

Also, look at you 29,000 subscribers 🎉🥳

[@barbaradurfee645]

If let that chubby cat share the screen you might get more viewers…..just sayin. Hugs to you both ❤ ❤

[@dweldredge]

Some cool scientific terms in this episode: "Kill Mechanism," "Death by Cooling," etc. :)

[@GEOGIRL]

Yea! I never thought about extinctions causes being categorized into 'kill mechanisms' vs 'triggers' until researching for this and the previous video on this topic. The papers I found used these terms and I found them incredibly useful and descriptive, they are also just cool as you said haha ;)

[@paul.a.clayton6640]

It seems that another factor would be long term environmental stability. Stability would encourage specialization and interdependence - which would tend to increase vulnerability to change, especially rapid change. I would guess that land mass elevation - particularly proximate to oceans? - could contribute to how much acidic rain increases nutrient delivery leading to algal bloom anoxia. Continental configuration - beyond correlations with vulcanism, orogeny, and weather/climate - might also affect the impact of extinction causes. A supercontinent might affect diversity, ability to escape by migration, range of similar niches (so localized accidental reductions in extinction cause impacts might be more likely to allow species/genera to survive), etc. The area of shallow ocean water (which might be related to continental configuration/elevations, ice coverage, or even, I seem to recall reading, sea floor spreading rate) might also - I am guessing - influence vulnerability to extinction, particularly when the impact is disproportionate for land and aquatic life. I appreciated how the video both brought out common threads and noted that simple single cause is not a good model for mass extinctions. Thinking casually and more abstractly about such can be fun, but I appreciate those that do actual research - the hard persistent work with the skill of asking effective questions - and those who make knowledge accessible to non-experts.

[@marksherry6589]

Thank you on your time and research. As your videos show science is usually not settled and your research is judged by the quality of enquiry and question put to you. Good job. I have no question as such but do suggest most of the information discussed can be identified in the past 200,000 years of solar and planetary behaviours in extensive documentation and observation,yes, even cave art as a human observation and much more. I look forward to any future advice.

[@mspicer3262]

Just a thought from a layman about why warming-events seem to cause more significant extinction events than cooling-events... chemistry. A lot of chemistry seems to work best when it's warm, than when it's cold. That should include harmful chemistry, as well as biochemistry, or other chemistry positive to life. I seem to recall, in the dustier parts of my brain, that quite a few reactions require quite specific temperature ranges, and they were always well above freezing.

[@juanmigueloctaviano6736]

it's crazy to think about all the different causes of mass extinctions, especially the lesser-known ones like the impact of nearby supernovae or gamma ray bursts

[@thhseeking]

Another great video, thanks :) When you mentioned Fluorine, that reminded me of Iceland. Laki caused a lot of deaths in 1783 from fluorosis. The 1783 eruption lasted about 7 months and killed some 20% of the human population and 80% of sheep & 50% of cattle & horses each from the fluorosis. The Siberian traps eruptions (and the later Deccan Traps eruptions) would have been far larger in extent and duration. Either way, let's hope that we don't have any more :P

[@barbaradurfee645]

Wow! I want to learn more about this. Thanks for sharing.

[@barbaradurfee645]

Are all volcanic eruptions rich in fluorine or are the ones in Iceland enriched?

[@barbaradurfee645]

Yikes!! In 1784, an eruption started in Lakagígar, which made the 2010 Eyjafjallajökull eruption look like a friendly campfire. It lasted for eight months with around 120 million tons of sulphur dioxide released into the atmosphere along with an estimated 8 million tons of hydrogen fluoride

[@thhseeking]

@@barbaradurfee645 Good question. I haven't seen any mention of Flourine in what I've read, but maybe it was only noticed in Iceland because of the people there and the nature of the eruption. Iceland is special because it's pretty much all volcanic as far as I know, whereas other volcanoes punch through sedimentary rocks mainly. Maybe the Flourine gets absorbed more in those cases?

[@SubtleForces]

While I understand the convenience of choosing "causes" and "triggers" as descriptors, I prefer when appropriate to use proximate cause and ultimate cause. They make the causal chain explicit. In this case, it highlights that the causes are "only" proximate causes and the ultimate cause must be examined to understand all the possible positive and negative feedback mechanisms. Of course, direct and indrect causes can not be equated to proximate and ultimate causes and I fully agree with how you use them in the video.

[@sanderspruit993]

Hi Geo Girl, I like your videos. Very factually rich and pleasantly presented. explaining the science behind the mass extinctions. Looking at events from the perspective of the survivors, what would this mean for us?

[@carcaperu4041]

As I understand the enormous damage done by the asteroid that hit the Earth at the end of the Cretaceous was due to the composition of the place were it hit. That if it had hit 15 minutes before or 15 minutes after, giving the planet time to rotate a little more or a little less, the damage to life would have been significantly less. I wonder if you, a geologist, could think of places were the hit would have been even worst. Places like a deposit of oil, or of lithium, or an igneous hot spot, or the Deccan Traps. And also think of which would have been the safest places to hit. the one causing the less damage to life.

[@nicholasmaude6906]

In regards to HF, Rachel, in the 1783 Laki eruptions ( en.wikipedia.org/wiki/Laki ) in Iceland about 20-25% of the population died mostly due to fluoride-poisoning.

[@Nick_BRZ]

GEO girl, you rock! 🪨 Keep up the great content. Educational but accessible with no ego. I hope you go far and inspire many to learn about the sciences and move our society forward for all. 🎉 👍

[@stevedrane2364]

Brilliant. . Thank you for your useful information. . Fascinating. . Oh we walk a very thin line on space ship Earth . . 👍

[@petermiesler9452]

2:00 ~ We need to be careful when labeling Precambrian Oxidation event, an extinction event. Anaerobic kingdom didn't go extinct, they went into hiding, but continued to thrive within their particular environmental niches. It was a rearrangement. In the long run, the rise of oxygen and the complex life that oxygen enabled, created ever more environments for Anaerobic organisms to find new niche far beyond what their pre-oxygen world promised. The Anaerobic kingdom has flourished within the oxidized world. (PS - Thanks for your interesting constructive videos!) 👍

[@GEOGIRL]

That's actually a great point! They greatly diminished in numbers and coverage, but many species survived. I am sure some anaerobic species went extinct, but knowing how resilient microbes are, I would assume that most survived then diversified in anoxic regions of the world thereafter. I mean heck, they even inhabit our guts now, so clearly they are innovative little guys! Thanks for pointing this out, it's important that we remember this event as a shift in dominant environmental niches and eventually dominant biota, but it wasn't necessarily a mass extinction event. :)

[@marcuspradas1037]

There's a recent paper saying that CH4 also has a cooling effect. But this cooling effect is more than countered by its warming effect. Another beautiful video once again, Rachel. You've got talent and most importantly, contagious passion.

[@الحمدلله-ع1ب3ث]

Hello,you should translate this video to arbic ,too. because we study this information in our school 🏫 and our university ❤. I'm new follower from "Egypt". Thanks for this information

[@GEOGIRL]

Done! Thanks for the feedback! I will try to make sure all my videos from now on are also translated to arabic :)

[@aresaurelian]

Artistic AI models can take snapshots of known earth historical states and interpolate, imagine, and project ideas and link these states coherently and in a compelling manner. If our snapshots are of enough fidelity and large enough dataset, the simulated artistic expression of the in between eras could provide new insights and even reveal hints of possible unknown injections that we still are missing.

[@secularsunshine9036]

I'm interested in the younger dryas, the black matt and the extinction of the megafauna. Thank you.

[@texelmicrorc]

Thank you for your videos which quench my thirst for geology and early life. Do you think you could make one sometime on fractal lifeforms? Thank you

[@teefkay2]

Something I’ve always wondered about, regarding the Cambrian extinction of 65 million years ago (due to the chixculub asteroid impact, which took out the dinosaurs) is simply the amount of dust & debris that was lofted into the upper atmosphere. I’ve read that amount of dust turned the day into night for an extended period. I’ve often wondered if that alone might have been a significant contributor. I think that predators which have evolved to hunt by eyesight during the day may make very poor predators if suddenly forced to hunt at “night”, and might just starve in a matter of weeks.

[@danwylie-sears1134]

After hearing the introductory statement, I'll guess pH changes, sea-level changes, rearrangement of ocean current patterns, and cascading effects of ecosystem disruption. I have the feeling I should be able to think of a few more. Ok, now to watch, and find out what extinction causes are actually in the video.

[@danwylie-sears1134]

Ok, I didn't do all that well at guessing. Next question that gets mentioned is why warming is involved in extinction events more than cooling. My guess for that is that warming can happen quickly, as long-sequestered greenhouse gases are suddenly released, but cooling happens slowly enough for life to adapt because there's no mechanism for sudden removal of those gases.

[@jensphiliphohmann1876]

About 19:00 f: In the graphic bottom left, 'D' seems to refer to diameter but what does 'Val' mean?

[@donaldbrizzolara7720]

Certainly not a main cause for mass extinction but I wonder if disease itself could be a contributing factor in the destruction of biological communities. Could, for example, certain viral entities arise that might negatively effect a broad spectrum of organisms? Any thoughts?

[@GEOGIRL]

I was JUST wondering this myself after making these two videos! I tried to search for "pandemic-caused extinction events" but I couldn't find anything because all the results are about the covid pandemic unfortunately lol. I will try some other search terms and see if I can find something. My guess is it likely contributed in some events, but we cannot necessarily see evidence of this in the fossil record, or maybe we don't know what to look for. But that is just my guess, I am not sure, maybe we do know what to look for and we've seen this in specific events. I will let you know if I find anything ;D

[@donaldbrizzolara7720]

An interesting modern example is the amphibian fungal killer that has caused the extinction of 90 frog species world wide and the decline of 491 other species. Imagine a worldwide fungal infection spreading during the Carboniferous, the heyday of amphibians. Yikes!

[@Strider_Bvlbaha]

Cultural anecdotes do not a scientific argument make, however, my people (Chahta, originally from the Southeastern corner of Turtle Island/N. America) maintain the reason the wooly mammoth and mastodon went extinct at the end of the last ice age is disease. I figure in any event where the climate is changing rapidly (but especially one where it is warming), disease is going to proliferate-- especially for social animals. I've thought before mammoth and mastodon should have survived into the present age; there are still places that feature plant communities similar to their preferred environments from their own time present today. There isn't any reason they could not have adapted to warmer climates, either--unless they were killed off before they had the chance. The whole thing about them being hunted into extinction is not particularly well founded, multiple Indigenous nations' oral traditions tell otherwise. However, rapid spread of disease among highly gregarious animals who conducted large migrations each year is reasonable apart from being attested to through oral histories. If it happened once, it probably happened more than once!

[@donaldbrizzolara7720]

Mason, that’s very interesting. Thanks so much for sharing.

[@dforrest4503]

Diseases are usually specific to certain species, so it seems unlikely they would cause a mass extinction, as you noted. However disease affecting a few keystone species could certainly trigger other effects.

[@a.randomjack6661]

Bonjour Geo Girl 🖖Love your videos, and Geology. I have 2 sorta questions. a) Are there acidification markers, and if so, what are they: shells, or is there a direct isotopic evidence or something? b) Isn't stratification of water (hot on top impairing vertical circulation of gases like O2 and nutrients in the waster column one of the important causes of de-oxygenation? I learned that warm water absorbs less O2 and, that all O2 used by life in the oceans comes from the the contact between water and the atmosphere. Which surprised me a bit I must say, but fish can't separate the O2 from water, they don't do electrolysis... yet. Thanks for making my Sunday mornings enjoyable 😃

[@nyoodmono4681]

When it comes to our interglacials, warming happens very rapidly due to probably drastic ice albedo reduction. Maybe this is a general rule and this could be a reason why warming would be the more severe extincton factor? Maybe also we have a too negative view on extincton events and underestimate the rate of changes, so the flourishing life just means that obsolete species go extinct quick. But then again we sometimes have these thick layers of missing fossils, which does not look very good at all for life..

[@unclewerner]

21:58 Hi, GG, someone below probably posted that already, but just in case I repeat that question here. Polar researches in the recent years got ever finer resolution of the sediment cores and there is now talk about the end of the last ice age being damn fast (within a year). I heard a public talk from a senior researcher of the Alfred Wegner Institute a few years ago at University Constanz, which hinted at the same order of events. That said, the well know geologist Robert Schoch put forth in his book "Forgotten Civilization" the theory of a solar outburst causing the sudden warming at the end of the last ice age. I'm not so into what civilization tend to record (mostly all rubbish anyways), but I lived a good decade near a glacial lake, which was said to be under 1km ice not so long ago. That landscape is so stunning and I'm wondering what today's geologist think about that particular latest extinction event. I know that ESA had studies in the 90-ies to classify the period of star explosions of different types of stars. Sadly not much is publicly available in a digestible form. Robert Schoch in his book on page 128 suggest nitrate spikes could be used as indicators for solar outburst events. And hence I wonder what you think about his theory of world wide plasma impacts causing mass extinctions and in particular triggering the rapid warming and loss of the Northern ice sheets during the Younger Dryas.

[@Tengooda]

" there is now talk about the end of the last ice age being damn fast (within a year)" Do you have any source for that claim? It certainly isn't what global temperature reconstructions show, nor does it seem at all physically possible. Here is Stefan Rahmstorf in 2022 discussing the Osman et al, 2021 graph of global temperatures over the last 24,000 years, which, of course, includes the end of the last glaciation: kzbin.info/www/bejne/pqW7pmaNp6iLoLM

[@IA52342]

"That's why warming is included and cooling is not" Hi Geo Girl, I am really enjoying all the FACTS you present here. As a fellow scientists (BS, MS, MIT, EE 71/73 & MS U Denver, Geographic Information Science, 2008) I would like to do some peer reviewing to assist you in upleveling your presentation. Logic is the key. Rock evidence does not prove that snowball earth should be included - correct. And at the same time, lack of rock evidence is NOT a valid basis for excluding snowball earth. It does not apply, therefore it does not apply in either direction. To accurately evaluate whether to include snowball earth as a cause of mass extinction, you are therefore thrown into the land of theoretical probabilities. Can you logically assign a probability to the theory that if a new snowball earth cycle hit us tomorrow, would any people die off as a result? And how many would die? Would it be 50% of the human population? 80%? Would Vladimir Putin stop selling natural gas to European nations? Thousands are already dying from freezing temperatures as his plans for total world domination move forward, both from energy shortages in winter in Europe, and from direct war crimes killing over 17,000 innocent people with his bombs and his tanks and his guns. Science is in a large part about making predictions. What do you PREDICT global cooling would produce in the form of a mass extinction event, if it were to start today?

[@mikehenry7056]

I remember a theory from a few years back that large-scale impacts could actually trigger volcanism from seismic waves coming together on the opposite side of the planet - for instance, the Chicxulub impact triggering the Deccan Traps eruptions.

[@quantumcat7673]

As always, very interesting piece for a geology enthusiast like me. I think that the Huronian glaciation and the Cryogenian have probably caused an extinction globally. What do you think?

[@GEOGIRL]

I completely agree, but again it is just impossible to say much directly about the fossil record of that time because there just isn't much of one haha. I wish the tiny soft life that was around back then was better preserved! I can only imagine what we could figure out with a more complete fossil record from the Precambrian!

[@artificercreator]

Thanks for the info!

[@NelsonDiscovery]

I just realized I don't really know what a gamma ray is. So I'm off to wikipedia. Thank you for the video and see you in the next one.

[@rogerdudra178]

Greetings from the BIG SKY. I agree with your perspective that a period of time with little evidence should be ignored.

[@robbabcock_]

Fascinating stuff!

[@AchanhiArusa]

What about the Manicouagan impact that occurred during the late Triassic? The impact event appears to have occurred with a spike in extinction rate at that time.

[@Giavani-t4k]

A great presentation. Lots to ponder. If I had to conjure a scenario of mass extinction and keep it real, the ultimate would be the state of volcanism on earth and an iron/nickel meteorite about two miles wide impacting the planet. The resulting cataclysmic destruction would light up a rather static volcanic state to full blown eruptions worldwide. Given the extremes environmentally, human kind would be hard pressed to survive in the coming decade. There is enough magma within earth to cover the surface perhaps a mile deep or far more. It seems the planet is poised for a calamity, and has been for a long time.

[@shadeen3604]

Thanks geo girl excellent

[@amirshay]

That was fascinating, thanks 🙌🏻

[@GEOGIRL]

Thanks! So glad you enjoyed it ;)

[@billrasmussen4716]

With the kt event, how much do you think ecosystem changes development of angiosperm plants have on the dinosaur, were they in decline before the meteor?

[@rogercroft3218]

How about muons? Some people have suggested that they might have played a role in some megafaunal extinctions.

[@GEOGIRL]

Oh wow, that's so interesting! I hadn't heard about that, but I'll look into it! Thanks for sharing ;)

[@jan_kisan]

two related points: 1. are there ways to tell apart falls in biodiversity versus biomass/number of individuals? 2. could you do a dedicated video on the biological factors in the history of biosphere - such as invasive species, especially in times of land bridges appearing; the resulting chemical changes (like the GOE); and so on? like, i understand that the current consensus emphasizes the volcanoes and asteroids and other non-biological factors and triggers, but i'm very much interested in how the biosphere develops itself, if you will. the major inner laws. there must be some. there always are, in whatever we study.

[@kerwinbrown4180]

Thank you for the information. Unfortunately I will need to hear it multiple times before it sticks.

[@GEOGIRL]

Don't worry, you are not alone. I will sometimes forget topics I've lectured about and have to rewatch my videos and I too have to watch 3 to 4 times hahaha ;)

[@marble296]

Rapid change is the killer?

[@GEOGIRL]

Yep pretty much :)

[@peterdore2572]

I love the CUTE giggle after you say: "Being hit by a Large Rock" 😂🤭

[@pjmoran42]

And yet with all these extinctions the earth comes back to a stable operating condition for life. I'm confident that it will continue once we're all gone. In the mean time have fun and enjoy the garden we've been gifted!

[@JSmith-ob6gh]

Happy Sunday!

[@estherclawson6876]

Geologic scale entropy is really cool.

[@danielchefkoch5582]

What about the connection between asteroid-impacts and the large magmatic provinces. From my experience as an engineer I know that every force needs an counterforce. So the energy of the asteroid impact has to go somewhere. Some is thrown up and some creates this nice craters, but the most force must go inside earth. So the magma inside earth must get a huge "push" causing waves that travel thru earth and become focused again on the opposite side, where they create an pressure pike. What I think is that these pressure pikes look for the most easiest way out and if there are already some minor cracks in the crust they will widen these massive and probably cause a new magmatic province. Is there any evidence for this theory?

[@billhollinshead]

Red tides on an oceanic or global scale?

[@brianstevens3858]

I'm going to recommend this channel to some other science and information based Yt'ers, If you get requests to talk or input from people you have never heard from don't be surprised.

[@GEOGIRL]

That is awesome! I would love to be in touch with other science youtubers! Thank you :D

[@wendydelisse9778]

With both a large scale volcanism and a large scale meteorite strike often comes widespread overly high concentrations of particulates. Vertebrates can experience respiratory distress from excess amounts of airborne particulates, particularly "warm-blooded" vertebrates that have higher metabolic rates per square meter of body surface area. At sea, a different problem can occur for one-celled organisms, having to do with density and size. Many species of one-celled foramifera just before the K-T boundary were much larger than any surviving modern species. Large and small, foramifera would have been weighed down by particulates. With two equally dense microscopic objects, the large microscopic object will sink much faster than a considerably smaller microscopic object, so larger species of foramifera were at a conderable disadvantage in an ocean with an overabundance of particulates on a time frame lasting for about a thousand years after the dinosaur killer meteorite. A 19th Century particulate experiment of French scientist Louis Pasteur demonstrated that point in a number of ways. Pasteur chemically created a suspension of tiny particles of gold in an aqueous solution. Gold is more than 10 times as dense as water, but a hundred years later, because the gold particles were so small, Pasteur's experiment was sitting in a French museum, with the particles of gold in still in suspension even though a hundred years had passed. Short version: An overabundance of particulates can cause respiratory problems in air breathing vertebrates, and at sea can create a whole host of problems on a century plus time scale, including the weighing down of larger-sized species of one-celled organisms. Overabundances of particulates should thus be looked at as a 4th main cause of extinction, alongside of rapidly lowered O2, rapidly raised CO2, and rapid global temperature fluctuation.

[@Deepintent]

What about the effects of solar aspects?

[@brentwilbur]

I walked away for a minute to flip my French toast and didn't feel like rewinding. Did you mention gamma ray bursts at all?

[@GEOGIRL]

Yep! That was the last slide in the video, but I didn't go into too much detail because I am no expect haha :)

[@brentwilbur]

@@GEOGIRL - Alright then, Angel. I will dutifully rewind it.

[@DenilsonBaiensedeLima-to1fy]

Wonderful!

[@GEOGIRL]

Thank you! ;)

[@markusgorelli5278]

Maybe with cooling events, animals would be likely to die on top a layer of snow or at least not buried in dirt. And so when the snow and ice eventually melts, those bodies would be exposed and decay rapidly.

[@oker59]

They've found the impact that caused the traps during the Permian extinction; it's under a bunch of Antarctic ice. In fact, they've come to see that each traps/Large Ignious provinces occur opposite an impact. They see an example on the planet Mercury There's a huge impact on one side, and volcanic ridges on the other side.

[@stevenbaumann8692]

You have to remember, unlike my channel, yours attracts a lot of non geo ppl. You'll get use to it.

[@HisameArtwork]

interesting, thanks for sharing!

[@tomhite3510]

One of my favorite channels to watch with my daughter. It is fun to learn from someone that is also learning. One observation is that influencers can be overly reliant on current ideological fashion. At times it seems the presenter is retrofitting observations to avoid cognitive dissonance with very recent passions on climate. For example, the presenter says that it is "hard to know how much damage" snowball Earth did to life on Earth (7min 5sec). Aaah, not really. The damage should qualify as an extinction event. It seems to me the influencer here wants to keep-with-the-program about global warming.

[@GEOGIRL]

No I meant it’s hard to know how much damage snowball earth did to life because of the lack of fossil record from that time, not because it was a cooling event. I think cooling events can be just as harmful as warming events, especially snowball earth, but we just don’t have the stats to really discuss the damage that snowball earth did. I just like to discuss the events that we have actual numbers for is all :)

[@tomhite3510]

I believe that I saw a video that snowball earth removed all mountains. Yikes! That doesn't sound good. Well, ah, that was 700mya. I understand there was no life on land at that time. On the other hand scraping all the mountains into the sea should be an event that would be the talk of the town.

[@FrancisFjordCupola]

Chicxulub and Deccan always sounded to me like "the whole is more than a sum of its parts". Same way that warmth is not as much an issue as not being evolved to deal with rapid warming; the combination of the impact plus the traps might just have been too pushy.

[@ianhorsham7751]

Yay! Even the UN are watching your videos!

[@ggtgp]

Chixilube was actually 100,000 years before the extinction and the Deccan traps was caused by three impactors that straddle the extinction. We got hit by a shotgun blast from a supernova.

[@basilbrushbooshieboosh5302]

Love your shows. Thanks

[@Stars4Hearts]

New sub! Nice channel!

[@jamesstaplesv]

what about when earths orbit move away from the sun too far as it has done cyclically ???

[@GEOGIRL]

Absolutely! That is something that can trigger or exacerbate climate trends, but it is more of a trigger for climate change than a cause of extinctions. In other words, it is not a direct 'kill mechanism' for life during extinciton events, but it may trigger climate change events that lead to extinction events. It is kind of similar to the role volcanism and impacts play in that sense :)

[@RobertPearsonJr]

I don't see any mention of pole shifts during these events or the earth magnetic field strength changes that happen during those periods. That can also cause ozone distruction and increased radiation hiting the Earth. A lot of current animals also rely on the magnetic field for migration and other biological functions. Also we've recently seen stars smaller/cooler than our sun have recurring nova events so it's no longer safe for us to say our sun 'can't do that'. The occurrence of such an event would explain cave drawings from civilizations across the globe that depict our sun doing odd things and the 'changes in the stars'. The fact that the stories and cave drawings exist all over the earth before people were able to spread a message from one side of the earth to another makes you think there are some things about our sun we don't yet understand. There are some really good research papers out there that talk about the magnetic pole shifts/magnetic field strengths in relation to extinctions and that evidence you can certainly find on the rocks. Just something to think about.

[@RavenRains]

Really like this one

[@2RANbit]

I am sorry to say this, but what impact do past extincion events have to do with the present day to day survival of the majority of human denizens on earth? I know, quite a lot of people might be offended by this view, but is the only thing they can think of doing is what authorities say they can? It is not like it feels like that is really safe environment... It doesn't really feel like what is generally deemed as a secure existence is actually a good enough basis factor for a content life, to be honest. There will always be factors that exceed what our species can possibly can control.

[@shdwbnndbyyt]

There was also a mass extinction event affecting the northern latitiudes of the Northern hemipshere about 536 AD, caused (per the survivng and recently translated Javanese royal chronicles). The volcano that most recently exploded in the 1800's known as Krakatoa had an even larger explosion, causing a tsunami so severe that it created a channel between Java & Sumatra, destroying the isthmus connecting them and the large metropolitian area located at the locarion. For the next several years, the sky was darkened and the crops failed. This effect was worse in the Northern Hemisphere where there was more land, where it cause the large scale abandonment of many cities due to lack of food. The darkening of the sky lasted longest in the areas of Northern portions of Europe, Asia and North America, and caused many forms of animal life to die out due to lack of food and increased hunting by humans and predators as alternative food sources failed. And this is the event from which we get the term... the Dark Ages.

[@caddothegreat]

A Byzantine Empire historian wrote of this event too. At least pointing out the dark skies and cold summers. Disease also came from Africa.

[@wendydelisse9778]

About 4 years later, another large volcanic eruption happened elsewhere. 4 years was not a sufficient amount of time for a full recovery in many locations, so the result was an extension of the time frame of disaster.

[@caddothegreat]

@@wendydelisse9778 Yes 541 AD in Central America. El Salvador area as I recall. The one that is active today. End of the Mayans ?