What Caused The Younger Dryas Cooling, Megafauna Extinctions, & Clovis Disappearance? GEO GIRL

If a mass extinction-causing asteroid or comet impact happened in the last 15,000 years, we would know about it, right? Not quite... There is still major controversy about an impact that may or may not have occurred around 12,900 years ago. In this video, we discuss the hypothesis that an impact caused major climate change and extinctions around 12,000 years ago, which is called the Younger Dryas Impact Hypothesis (YDIH). In a recent video (   • How Did Pleistocene Megafauna Go Extinct? ...  , I covered the Pleistocene megafauna (e.g., mammoths, mastodons, giant ground sloths, etc) that lived from about 2.6 million years ago until around 11,000 years ago. Many species of megafauna went extinct around the same time during a rapid cooling event called the Younger Dryas. However, what caused the Younger Dryas cooling remains debated, which is the topic of this video. Some hypothesize it was an extraterrestrial impact (i.e., the YDIH), some hypothesize a super volcano erupted releasing massive amounts of ash that blocked sunlight and caused cooling, and some hypothesize that a change in ocean circulation (shut down of the AMOC) due to the preceding warming trend was the cause for the switch to global cooling. In this video, I cover these possibilities (mainly the impact & ocean circulation possibilities), the evidence behind them, and their likelihood based on current data. Hope you enjoy! ;D 0:00 What was the Younger Dryas? 1:11 When was the Younger Dryas? 2:55 Unknown cause of Younger Dryas? 3:58 YD Impact Hypothesis 4:55 Impact evidence 7:20 Missing evidence 10:21 Extinction of Clovis people? 11:31Extinction of megafauna? 13:02 Is there a crater? 14:21 Other causes of the YD cooling 15:04 Ocean circulation cause 18:43 Similar ocean circulation changes today 21:03 Summary of YD Impact Hypothesis References: Rethinking megafauna: https://royalsocietypublishing.org/do... Late survival of megafauna refuted for Cloggs Cave, SE Australia: Implications for the Australian Late Pleistocene megafauna extinction debate: https://www.sciencedirect.com/science... Relationships between climate change, human environmental impact, and megafaunal extinction inferred from a 4000-year multi-proxy record from a stalagmite from northwestern Madagascar: https://www.sciencedirect.com/science... Environmental drivers of megafauna and hominin extinction in Southeast Asia: https://www.nature.com/articles/s4158... YDIH specific refs: Holliday et al., 2023: https://doi.org/10.1016/j.earscirev.2... Powell, 2022: https://doi.org/10.1177/0036850421106... Sweatman, 2021: https://doi.org/10.1016/j.earscirev.2... GEO GIRL Website: https://www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, & donate to support the channel if you'd like!) Hey there, Earth enthusiast! Check my favorite Earth-friendly products: Bamboo toilet paper: https://shrsl.com/3cvku Bamboo paper towels: https://shrsl.com/3cvkw Compostable tableware: https://shrsl.com/3cvkz Compostable trash bags: https://shrsl.com/3cvl0 Bamboo cutlery + straw! : https://shrsl.com/3cwfl Eco-Friendly Tote (great for grocery shopping!): https://shrsl.com/3cwfp Reusable straws + cleaning brushes (my fav!): https://shrsl.com/3cwft Eco-friendly laundry detergent: https://shrsl.com/3cwgo Directly offset your carbon footprint with Wren: https://shrsl.com/3d0t2 (Just click link, press get started, take the free C footprint quiz, then choose how much you want to reduce your footprint by donating to the C sequestration projects they're funding!) Non-textbook books I recommend: Oxygen by D. Canfield: https://amzn.to/3gffbCL Brief history of Earth by A. Knoll: https://amzn.to/3w3hC1I Life on young planet by A. Knoll: https://amzn.to/2RBMpny Some assembly required by N. Shubin: https://amzn.to/3w1Ezm2 Your inner fish by N. Shubin: https://amzn.to/3cpw3Wb Oxygen by N. Lane: https://amzn.to/3z4FgwZ Alien Oceans by K. Hand: https://amzn.to/3clMx1l Life's Engines: https://amzn.to/3w1Nhke Tools I use as a geologist/teacher/student: Geology field notebook: https://amzn.to/3lb6dJf Geology rock hammer: https://amzn.to/3DZw8MA Geological compass: https://amzn.to/3hfbdLu Geological hand lens: https://amzn.to/3jXysM5 Camera: https://amzn.to/3l6fGRT Carbon-neutral pencil bag: https://shrsl.com/3cvjv Carbon-neutral backpack: https://shrsl.com/3cvkc Disclaimer: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission, but there is no additional charge to you! Thank you for supporting my channel so I can continue to provide you with free content each week! And as always, let me know your topic suggestions in the comments down below!