Around 650 million years ago, the Earth entered into the Marinoan glaciation where the entire planet froze. The “Snowball Earth” restricted the evolution of life. But when it warmed, biotic life began to flourish. A research team from Tohoku University has studied rock samples from China to tell us more about this transition.
Some researchers believe that ice sheets covered the earth during the Marinoan glaciation (650 – 535 million years ago) in what is referred to as “Snowball Earth.” The glaciation also affected the climate and chemical compositions of the oceans, restricting the evolution of early life. Yet, as the earth warmed, and the Ediacaran period began, biotic life began to evolve.
Using biomarker evidence, the team revealed possible photosynthetic activity during the Marinoan glaciation which was followed by photosynthetic organisms and bacteria entering a period of low productivity. As the eukaryotes expanded during the early Ediacaran period, they blossomed.
During The late Neoproterozoic era (650 – 530 million years ago) the Earth experienced one of the most severe ice ages in its 4.6 billion year history. Researchers believe that ice sheets covered the entire earth. Overlaying these glaciers are cap carbonates which precipitate under warm conditions and suggest that the glacial environment changed rapidly into a greenhouse environment.
The snowball Earth hypothesis suggests the atmospheric carbon dioxide concentration controlled the change from a frozen state to an ice-free state. Ice sheet-covered oceans prevented carbon dioxide from dissolving into seawater during the Marinoan ice age, meaning greenhouse gas concentration, emitted by volcanic activity, increased gradually. Once the greenhouse gas effect kicked in, glaciers melted and excess carbon dioxide precipitated on glacier sediments as cap carbonates.