What Caused The Younger Dryas Cooling, Megafauna Extinctions, & Clovis Disappearance? GEO GIRL
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Published 2024-07-07
In a recent video ( • How Did Pleistocene Megafauna Go Exti... , 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: royalsocietypublishing.org/doi/full/10.1098/rspb.2…
Late survival of megafauna refuted for Cloggs Cave, SE Australia: Implications for the Australian Late Pleistocene megafauna extinction debate: www.sciencedirect.com/science/article/abs/pii/S027…
Relationships between climate change, human environmental impact, and megafaunal extinction inferred from a 4000-year multi-proxy record from a stalagmite from northwestern Madagascar: www.sciencedirect.com/science/article/abs/pii/S027…
Environmental drivers of megafauna and hominin extinction in Southeast Asia: www.nature.com/articles/s41586-020-2810-y
YDIH specific refs:
Holliday et al., 2023: doi.org/10.1016/j.earscirev.2023.104502
Powell, 2022: doi.org/10.1177/00368504211064272
Sweatman, 2021: doi.org/10.1016/j.earscirev.2021.103677
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All Comments (21)
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I watch a lot of geology, anthropology, archeaology, history, and science channels on YouTube. I enjoy your channel, it’s one of my favorites. Thank you.
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Younger Dryas sounds like it could be a Jethro Tull song title.
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Thanks for your videos! I was able to get my professional geology license in no small part to watching all your videos on repeat. Such good content and your presentation is great!
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Super nice summary of the YD cooling event. One puzzling thing about the YD, that has been the focus of my research and others who work in Chukotka, NE Siberia and parts of Alaska, is the apparent absence of a YD cooling in quite a few lacustrine and terrestrial depositional records.
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I really appreciate all those clarifications. Excellent research .You rock Dr. 👍
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Your presentation only seems to get better with each video. Love your content and I learn so much with each video. It's so easily digestible as a layman. Also great bedtime/sleep video as well. Looking forward to the next one!
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Yes! One of my favorite topics!!! Thank you for another great video!
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Thanks - very cool and objective coverage of the YD. I read somewhere that the YD also caused arid conditions in the fertile crescent that led to, or at least coincided with, the origin of agriculture.
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Thank you, Doc, -- another fascinating presentation -- my side focus in grad school was the old KT impact -- and all the subsequent impact events -- I look forward to all your ideas.
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Thanks for speaking theoretically and indicating more study and data is needed. It’s so refreshing. Belief in Science has been damaged over the years by claims that theories are facts.
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The cat: "Dont Youtube. PET ME NEOW" 😸
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You're the 4th or 5th YT paleontology channel (Eons, Raptorchatter, North02, et al) I've seen having to debunk the YDIH; and have done the best job explaining it. The visuals help a lot!
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You continue to amaze me given your busy busy life. I loved this video & I also loved your strategic call today, the reaction here was actually acceptance 😊😉 and acknowledgement of your good judgement. ❤️
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This has always been one of my favorite topics that I could never fully keep up with—great overview! If you're interested, we looked in detail at the precise timing of Younger Dryas cooling and its synchroneity with Asian Monsoon weakening, using speleothems from W. Europe, China, and Brazil. We concluded that the inception of cooling predated the impact, which had minimal effect: Cheng et al., 2020, PNAS, doi:10.1073/pnas.2007869117
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I think the Carolina bays geological features are some evidence of an impact event.
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As an avid Native American projectile point collector, I can assure you the Clovis never went anywhere. We can see a direct progression in lithic types spanning thousands of years without interruption. First Clovis, then Redstone, Folsom, Cumberland, Beaver lake, Dalton, etc, etc.. All very closely related. In fact, they're still here.
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Tell your cat I said hi. 👋
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Your cat is always welcome to make an appearance.
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Wonderful discussion Rachel. Absolutely fascinating. Thank you for all your good works. You have such a great gift and I truly appreciate it.
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Thank you for the clarity and references!!
