The 'Big 5' Mass Extinctions of the Phanerozoic Eon (within the last 540 million years) get the most attention due to the more complete fossil record of this time. However, there were mass extinction events long before 540 million years ago; they are just harder to quantify due to the lack of preservation of the microbial life that lived during that time. In this video, I talk about a mass extinction event that occurred over 700 million years ago and was potentially larger than all the of Big 5 mass extinction events since! This mass extinction event was caused by the Cryogenian Snowball Earth event, during which Earth's oceans were nearly completely covered in ice, leading to extremely limited photosynthesis, a rapid global increase in seawater salinity and viscosity, major ocean stagnation due to lack of circulation and mixing under the ice, and thus, major biological devastation and extinctions. Hope you enjoy! ;)

0:00 Rise of Oxygen on Earth
3:04 Snowball Earth
5:15 Snowball Earth & Explosions of Life
6:49 Snowball Earth & Extinctions of Life
8:00 Argument for “Slush Ball” over “Snowball”
11:06 Where & How Life Survived
11:29 Other Extinction Causes
14:40 2nd Mass Extinction?
15:33 Explosions of Life after Snowball Earth
16:33 Was this the Largest Extinction of All Time?

References:
Halling et al., 2024: Snowball Earth viscosity drives multicellular evolution- https://doi.org/10.1101/2024.02.06.57...
Hoffman et al., 2017: Snowball Earth climate dynamics and Cryogenian geology-geobiology- https://doi.org/10.1126/sciadv.1600983
Griffiths et al., 2022: Animal survival strategies in Neoproterozoic ice worlds- https://doi.org/10.1111/gcb.16393
Casado, 2021: Review of the Neoproterozoic Global Glaciations and a Biotic Cause of Them- https://doi.org/10.1007/s41748-021-00...
Gan et al., 2022: Earliest Ediacaran speleothems and their implications for terrestrial life after the Marinoan snowball Earth- https://doi.org/10.1016/j.precamres.2...
Earth System History: https://amzn.to/3v1Iy0G
Geomicrobiology: https://amzn.to/2WAloTR
Ediacaran Extinction & Cambrian Explosion- https://doi.org/10.1016/j.tree.2018.0...
Anoxia during Ediacaran- https://doi.org/10.1126/sciadv.aan8983
Ediacaran Mass Extinction- https://doi.org/10.1098/rspb.2015.1003
Hydrogen sulfide increase in ocean during Ediacaran-Cambrian transition- https://doi.org/10.1038%2Fnature07072

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!)

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Bamboo toilet paper: https://shrsl.com/3cvku
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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!