Tectonics are the large scale geological processes that alter the structure of the Earth's crust.
The rigid outermost shell of the planet, called the lithosphere, consists of the crust and upper mantle. It is fractured into a number of plates that slide across the lower mantle, forming cratons and oceanic trenches.
The lithosphere formed approximately 4 billion years ago, following the cooling that occurred after the Hadean eon. This cooling allowed a crust to form on Earth’s surface, and since then, continents have continually built up, broken apart, and shifted across the planet.
Fissures at the base of oceanic trenches are caused by plate tectonics and are now being investigated as a possible source or location for the origin of life. Many astrobiologists suggest that tectonic activity on other planetary bodies may indicate the potential for life.
It has been hypothesised that tectonic activity not only contributed to the emergence of life but also acts as a primary engine driving subsequent evolutionary processes. Genetic variation underpins biological evolution; similarly, environmental variation influences extinction and repopulation rates. Tectonic activity has been the dominant force behind long-term environmental change, shaping continents, oceans, mountain formation, and global temperature variation.
While tectonic activity is not the sole driver of environmental processes—particularly after life emerges and biological feedback loops develop—it may be the single most significant factor influencing the origin and evolution of life on the planet.
