Eoarchean Era

Biological

• Earth's magnetic field is not present until 3.5 Ga, thus not available to protect life from cosmic radiation

  • Early prokaryotes would have been able to survive due to protection by using polyphosphate manganese, to protect against oxidative stress (Dai et al., 2023)

  • The living bacterium Deinococcus radiodurans uses a similar mechanism to protect against radiation.

• Graphite, found in the 3.95-billion-year-old rocks, shows the geochemical signature of having come from the decomposition of living organisms (Tashiro et al., 2017)

• Evidence suggests prokaryotes may have evolved during this time

  • Early life probably used methane as an energy source 

  • Possible evidence of stromatolites from Greenland sediments at 3.7 Ga (Nutman et al., 2016)

• Microscopic filaments and tubes, which appeared to have been made by iron-loving bacteria, in rocks from the Nuvvuagittuq Supracrustal Belt in Québec, Canada (Papineau et al., 2022)

  • In 2017, Tiny filaments and tubes were discovered and attributed to bacteria that lived on iron, and now found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB), Quebec, Canada (Dodd et al., 2017)

  • Further examination reveals structures such as a "stem" with parallel branches on one side that is nearly 1 cm long — as well as hundreds of distorted spheres, or ellipsoids, alongside the tubes and filaments

  • These structures date to 3.75 - 4.28 Ga and suggest that a variety of microbial life may have existed on primordial Earth, potentially as little as 300 million years after Earth's formation

• The conditions needed to create the first protocell for life were probably alkaline hydrothermal conditions which "...not only permit protocell formation at the origin of life but actively favour it” (Jordan et al., 2019)

• Another hypothesis states that the origin of life started in "fluctuating volcanic hot spring pools" (Damer & Deamer, 2020)