700 Million Years Ago, Our Planet’s Coldest Ocean Temperatures Arrived During A Mysterious Era: Snowball Earth
IFLScience • • science
Key Points:
- Snowball Earth refers to at least two periods when the planet was almost entirely frozen, significantly colder than the ice age 12,000 years ago, and is thought to have influenced the emergence of complex life by releasing nutrients into the oceans.
- Banded iron formations (BIF), which require low dissolved oxygen to form, reappeared during Snowball Earth as ice blocked atmospheric oxygen from reaching the oceans, contrasting with earlier BIFs formed before the Great Oxygenation Event.
- A recent study found differences in iron isotope ratios in BIFs from before the GOE and Snowball Earth, potentially explained by temperature fractionation occurring in extremely cold, salty ocean brines around -15°C, suggesting highly saline pockets of liquid water despite widespread
