Search the Community

I'm wondering if anyone has any knowledge of what I should look for when determining the obvious signs of the O-S boundary. If there is a general strata or formation I should keep my eyes open for when looking for it? I keep seeing a reddish boundary when I search for it online. However, I can't find any pictures from anywhere within 1000 miles of where I am, so am a bit skeptical. Any help would be great! A clear picture would be better! This image is from Manitoba, Canada. It's description is a bit vague.

Found in Silver City New Mexico Greetings, I was looking to get an I D or more specifically a species. The entire specimen measures 10.71 cm x7.62 . It's the first find of it's kind for me.

I spent two days observing the coast of half moon bay along a 2 mile stretch of land. I made this because if it is true, it would place an extinction event between 2 recorded ones.

Many Newly Discovered Species Are Already Gone Scientists are uncovering previously unknown species preserved in museum and botanical garden collections, only to find that they no longer exist in the wild. Katarina Zimmer, Wired, June 10, 2023 Undark version of above article. The paywalled paper is: Solórzano-Kraemer, M.M., Kunz, R., Hammel, J.U., Peñalver, E., Delclòs, X. and Engel, M.S., 2022. Stingless bees (Hymenoptera: Apidae) in Holocene copal and Defaunation resin from Eastern Africa indicate Recent biodiversity change. The Holocene, 32(5), pp.414-432. PDF of preprint of Solórzano-Kraemer et al. (2022) Yours, Paul H.

I am a new member of this forum, and I hope some of you will enjoy a somewhat different approach to the topic of dinosaur extinction. As a philosopher and a computer software architect for over 50 years, I dig things a different way. Of course I have always been interested in dinosaurs. What got me really excited about the problem of dinosaur extinction a few decades ago, was learning that there are two families of birds. Birds with teeth all died out with the dinosaurs. Birds without teeth lived on to be the ancestors of the birds we have today. Thinking about this led me to develop "The Last Gasp Theory" of dinosaur extinction. I wrote a book about it and self-published on Amazon in 2008. (I am not trying to sell a book here, I'm going to give a quick synopsis of the ideas here.) We know that dinosaurs and mammals lived at the same time. How could it be that all the dinosaurs (except birds without teeth) died, while the mammals lived on? One way to describe this would be to say that the environment the dinosaurs were adapted to rapidly disappeared all over the world at once, while the environment that the mammals were adapted to, continued on to the present day. But how can there have been two separate environments at once, that extended around the world? The answer that comes to my mind immediately, is the atmosphere. If we assume for this argument that the atmosphere of the Earth at the time of the dinosaurs contained a much greater amount and percentage of oxygen, several things could also be true. Dinosaurs could be a special adaptation to a higher oxygen environment, with special lungs, stronger muscles, and perhaps stronger bones than other animals including mammals. These of course are things that might not be obvious from first examination of their fossils, but might be inferred from the support of the larger specimens, the depth and inclination of footprints, and other things you will think of. Looking at mammals from this perspective, you might notice that the major traits of mammals all point to an adaptation for living in cold weather at least part of the time. Hair, constant body temperature, live birth, suckling the young. Now lets add one more trait that is not obvious to us today: they were and are adapted to thin air, which the dinosaurs were not adapted to (except perhaps the birds without teeth.) In a thicker, denser atmosphere, the environment near sea level would have been warm. A thicker atmosphere also leads to a faster decrease in air density with an increase in altitude. Assuming the dinosaurs were adapted to the environment of the lowlands, and mammals were adapted to the only place it could be cold, at higher altitudes, perhaps they lived separate lives, almost as if they lived on different planets.. (by the way, Hal Clement's science fiction classic "A Mission of Gravity" offers a perspective on this idea.) The mechanism of the extinction is simple. A large asteroid hits Earth and scrapes a 60 mile (100 km) trough thru the outer crust. This releases a humongous amount of abiotic hydrocarbons. These hydrocarbons are eaten by bacteria, who convert them to CO2 and water. Very rapidly, the environment that favors the dinosaurs and their cousins in the air and the oceans, can no longer breathe. Birds with teeth go along with them. Birds without teeth, who have perhaps adapted to thinner air, live on and we get to call them "dinosaurs". Many mammals move downhill to expand their territory. One thing this suggests is that we might want to expand the label of dinosaurs to other animals that did not share their common pelvic structures. Another is that this could happen again, to us, with another large Earth impact. Of course, we will have more to worry about than thin air if that happens. As an aside to this theory, I'd like to offer a conjecture. I think that one of the influences that has driven evolution on a larger scale, is both decreases and increases in oxygen. Of cou8rse the development of plants has increased the free oxygen or elemental oxygen in the air, making oxygen-breathing animal life possible. I also think the total amount of oxygen in the air goes up and down over millions of years. The mechanism as I imagine it, is that meteors, asteroids, and perhaps microcoments containing water rain down on the earth constantly. Then H2O disassociates into hydrogen and oxygen atoms in the upper atmosphere. The action of the solar wind strips off the lighter hydrogen ions which are lost to space. The far heavier oxygen atoms fall back, and increase the concentration in the atmosphere, which at one point benefitted ceolophysis . becoming the grandaddy to the dinosaurs. At other times, abiotic hydrocarbons are released and thin the air again. I hope some of you have enjoyed my introduction. Even though it is not based on fossils except in an indirect way, I hope some of you can use these ideas. You should have seen me at 12 years old encountering dinosaur fossils at a museum in Albany NY in the mid 1960s! -Brad Jensen

Some hints on the extinction of our cherished Meg: Trophic position of Otodus megalodon and great white sharks through time revealed by zinc isotopes (link to nature communications) Great white sharks may have contributed to megalodon extinction (link to science daily) Franz Bernhard

Mammoths and other large animals survived in the north much longer than previously believed. New DNA research indicates that the climate, not humans, led to the demise of these large creatures, Norway Science, January, 2022 The open access paper is: Wang, Y., Pedersen, M.W., Alsos, I.G., De Sanctis, B., Racimo, F., Prohaska, A., Coissac, E., Owens, H.L., Merkel, M.K.F., Fernandez-Guerra, A. and Rouillard, A.,2021. Late Quaternary dynamics of Arctic biota from ancient environmental genomics. Nature, 600(7887), pp.86-92. It concludes that mammoths survived in continental northeast Siberia until 7,300 BP; North America until 8,600 BP; and the Taimyr Peninsula as late as 3,900 BP. Yours, Paul H.

At Tanis, scientists studied the remains of three sturgeons and three paddlefish, using in particular high-resolution X-ray tomographic analysis from the Grenoble European Synchrotron (ESRF). They first established that the fish had indeed perished in the seiche episode, which was accompanied by a rain of glass spherules... https://www.cnn.com/2022/02/23/world/asteroid-dinosaur-extinction-spring-scn/index.html The research is described in a paper published Wednesday (Dec. 8) in the journal Scientific Reports.

https://www.sciencedaily.com/releases/2021/08/210811113120.htm "over the last 20,000-50,000 years birds have undergone a major extinction event, inflicted chiefly by humans, which caused the disappearance of about 10%-20% of all avian species" "68% of the flightless bird species known to science became extinct"

Mysterious event nearly wiped out sharks 19 million years ago By Yasemin Saplakoglu, Live Science, June 3, 2021 "It's unknown whether the ancient sharks died off in a single day, weeks, years or even thousands of years." The paper is: Elizabeth C. Sibert and Leah D. Rubin, 2021 An early Miocene extinction in pelagic sharks Science 04 Jun 2021: Vol. 372, Issue 6546, pp. 1105-1107 DOI: 10.1126/science.aaz3549 Yours, Paul H.

Ancient kauri trees capture last collapse of Earth’s magnetic field By Paul Voosen, Science, February 18, 2021 Ancient Trees Show When The Earth's Magnetic Field Last Flipped Out By Nell Greenfield-Boyce, Short Wave, NPR, February 18, 2021 Buried treasure - subfossil swamp kauri By Kate Evans, New Zealand Geographic Voosen, P., 2021, Kauri trees mark magnetic flip 42,000 years ago Science. vol. 371, Issue 6531, pp. 766 DOI: 10.1126/science.371.6531.766 The paper is: Cooper, A., Turney, C.S.M., Palmer, J. and others, 2021, Global environmental crisis 42,000 years ago Science. Vol. 371, Issue 6531, pp. 811-818 Related paper Staff, R.A., Hardiman, M., Ramsey, C.B., Adolphi, F., Hare, V.J., Koutsodendris, A. and Pross, J., 2019. Reconciling the Greenland ice-core and radiocarbon timescales through the Laschamp geomagnetic excursion. Earth and Planetary Science Letters, 520, pp.1-9. Yours, Paul H.

Why did trilobites go extinct? By Donavyn Coffey, Live Science, November 2020 https://www.livescience.com/why-trilobites-went-extinct.html The open access paper is: Jonathan L. Payne, Alexandra V. Turchyn, Adina Paytan, Donald J. DePaolo, Daniel J. Lehrmann, Meiyi Yu, and Wei, Calcium isotope constraints on the end-Permian mass extinction. PNAS May 11, 2010 107 (19) 8543-8548 https://www.pnas.org/content/107/19/8543 A totally unrelated article is: The role of cat eye narrowing in cat-human communication by Ellie Bennett, Snippet Science, November 2020 https://www.snippetscience.com/the-role-of-cat-eye-narrowing-in-cat-human-communication The open access paper is: Humphrey T, Proops L, Forman J, Spooner R and McComb K. The role of cat eye narrowing movements in cat-human communication. Sci Rep. 2020 Oct. 10, 16503 https://doi.org/10.1038/s41598-020-73426-0 Yours, Paul H.

Burning Fossil Fuels Helped Drive Earth’s Most Massive Extinction https://www.nytimes.com/2020/11/18/science/extinction-global-warming.html?surface=home-discovery-vi-prg&fellback=false&req_id=829253552&algo=identity&imp_id=724592622&action=click&module=Science Technology&pgtype=Homepage

Thought this fit better here than general fossil discussion but I thought it would be fun if we talked about what it was like on that day 66 million years ago. You know it has to be a great day. What was the weather like? The day of the year? The time of day? What the dinos were doing? What on Earth was going on?

Hi everyone, Last year we visited a dinosaur show (I believe something like "DinoExpo") in our area in the Alsace (France), where they screened a film about the meteor-strike that killed the dinosaurs. It was spoken in French (though could of course have been voiced-over) and I hadn't seen it before. However, my wife, who normally isn't overly interested in anything dinosaur liked it a lot, to the extent of asking me afterwards whether I could find it so she could finish watching it. As I don't know where to start on it, I thought I'd ask here... So, the documentary's most defining features I remember: 1. It's a 3D animation 2. The topic is the timeline of the impact of the meteor that killed the dinosaurs 3. This timeline is used to explain events that occurred around the world immediately prior and immediately following the impact on an hour by hour pace 4. There seemed to be a greater emphasis on Mongolian dinosaurs than most documentaries I've seen Any pointers in the right direction would be greatly appreciated!

For ancient deep-sea plankton, a long decline before extinction University of Buffalo, Press release by Charlotte Hsu Sheets, H.D., Mitchell, C.E., Melchin, M.J., Loxton, J., Štorch, P., Carlucci, K.L. and Hawkins, A.D., 2016. Graptolite community responses to global climate change and the Late Ordovician mass extinction. Proceedings of the National Academy of Sciences, 113(30), pp.8380-8385. Researchgate PDF for above paper Related publications Yours, Paul H.

Exploding stars may have caused mass extinction on Earth, study shows, University of Illinois at Urbana-Champaign, August 18, 2020 "Killer cosmic rays from nearby supernovae could be the culprit behind at least one mass extinction event, researchers said, and finding certain radioactive isotopes in Earth's rock record could confirm this scenario." The open access paper is: Brian D. Fields, Adrian L. Melott, John Ellis, Adrienne F. Ertel, Brian J. Fry, Bruce S. Lieberman, Zhenghai Liu, Jesse A. Miller, Brian C. Thomas. Supernova triggers for end-Devonian extinctions. Proceedings of the National Academy of Sciences, 2020; 202013774 Yours Paul H.

They sequenced 14 woolly rhino genomes and found that they co-existed with humans for thousands of years with stable population sizes. They then conclude that humans did not cause the extinction, but warming of the climate did. What if wooly rhino just tasted bad? Then humans wouldn't hunt them until the other megafauna were extinct. Or we invented barbeque sauce. Then they would disappear in a blink of an eye. Anyway here's the news article: https://phys.org/news/2020-08-ancient-genomes-woolly-rhinos-extinct.html

Asteroid shower rained space rocks on Earth and the moon 800 million years ago By Charles Q. Choi, SpaceCom, July 21, 2020 Asteroid shower on the Earth-Moon system 800 million years ago revealed by lunar craters by Osaka University, PhysOrg, July 21, 2020 The open access paper is: Terada, K., Morota, T. & Kato, M. Asteroid shower on the Earth-Moon system immediately before the Cryogenian period revealed by KAGUYA. Nature Communications (2020). DOI: 10.1038/s41467-020-17115-6 Yours, Paul H.

Just found this about the Permian extinction/the great dying, earths greatest mass extinction. https://www.artsci.utoronto.ca/news/geochronologists-shed-light-earths-greatest-mass-extinction

News article: https://www.miragenews.com/fossil-discoveries-reveal-cause-of-megafauna-extinction/ Open access article: https://www.nature.com/articles/s41467-020-15785-w

Racki, G., 2020, Volcanism as a prime cause of mass extinctions: Retrospectives and perspectives, in Adatte, T., Bond, D.P.G., and Keller, G., eds., Mass Extinctions, Volcanism, and Impacts: New Developments: Geological Society of America Special Paper 544, p. 1–34 https://www.researchgate.net/publication/337951571_Volcanism_as_a_prime_cause_of_mass_extinctions_Retrospectives_and_perspectives https://www.researchgate.net/profile/Grzegorz_Racki Racki, G., Rakociński, M., Marynowski, L. and Wignall, P.B., 2018. Mercury enrichments and the Frasnian-Famennian biotic crisis: A volcanic trigger proved?. Geology, 46(6), pp.543-546. https://www.researchgate.net/publication/326031821_Mercury_enrichments_and_the_Frasnian-Famennian_biotic_crisis_A_volcanic_trigger_proved Let's be careful out there, Paul H.

I read "The Story of the Dinosaurs in 25 Discoveries" by Donald R. Prothero. The author states that paleontologists now mostly do not think that the Chicxulub metor impact killed off the non-avian dinosaurs, and that other explainations are preferred. He did not really explain this statement. That certainly was news to me! I am no professional though. What's the truth?

One of World's Largest Freshwater Fish May Be First Official Extinction of 2020 By Stephanie Pappas, Live Science, January 07, 2020 https://www.livescience.com/chinese-paddlefish-extinct.html This enormous ancient fish is officially extinct By Eva Frederick, Science, Jan. 7, 2020 https://www.sciencemag.org/news/2020/01/enormous-ancient-fish-officially-extinct The paper is: Zhang, H., Jarić, I., Roberts, D.L., He, Y., Du, H., Wu, J., Wang, C. and Wei, Q., 2020. Extinction of one of the world's largest freshwater fishes: Lessons for conserving the endangered Yangtze fauna. Science of The Total Environment, 710, p.136242. https://www.sciencedirect.com/science/article/pii/S0048969719362382 Yours, Paul H.

Human impact on nature 'dates back millions of years' By Helen Briggs, BBC News, January 20, 2020 https://www.bbc.com/news/science-environment-51068816 The open access paper is: Faurby, S., Silvestro, D., Werdelin, L. and Antonelli, A., Brain expansion in early hominins predicts carnivore extinctions in East Africa. Ecology Letters. https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13451 https://www.ncbi.nlm.nih.gov/pubmed/31943670 Yours, Paul H.