Prekambrisillä

Prekambrisillä refers to the geological eon that predates the Cambrian period. It encompasses the vast majority of Earth's history, stretching from the formation of the planet approximately 4.6 billion years ago to the beginning of the Cambrian explosion, about 541 million years ago. This immense span of time is often divided into several eras: the Hadean, the Archean, and the Proterozoic.

During the Prekambrisillä, fundamental geological and biological processes occurred. The Earth's crust solidified, the atmosphere and oceans formed, and the earliest forms of life, primarily simple single-celled organisms like bacteria and archaea, emerged. The development of photosynthesis by some of these early life forms led to a significant change in the atmosphere, causing the Great Oxygenation Event and paving the way for more complex life forms to evolve later.

Fossil evidence from the Prekambrisillä is relatively scarce, often consisting of stromatolites (layered structures formed by microbial mats) and microfossils. Much of our understanding of this eon comes from studying ancient rock formations, isotopic dating, and the geological record of planetary formation. The Prekambrisillä laid the groundwork for the diversification of life that characterized subsequent geological periods.