Piezonuclear reactions, which occur in inert and nonradioactive elements, are induced by high pressure and, in particular, by brittle fracture phenomena in solids under compression. These low energy reactions generally take place in nuclei with an atomic weight that is lower or equal to that of iron (Fe). The experimental evidence, obtained from repeatable measurements of neutron emissions, can be also recognized considering the anomalous chemical balances of the major events that have affected the Earth's crust, oceans and atmosphere, over the last four billion years. These anomalies include: (i) the abrupt variations in the most abundant elements in correspondence to the formation of tectonic plates; (ii) the Great Oxidation Event (2.7 to 2.4 billion years ago), with a sharp increase in atmospheric oxygen and the subsequent origin of life; (iii) the increase of carbon and nytrogen concentrations in the primordial atmosphere.

Natural piezonuclear reactions are induced by fault sliding and plate subduction phenomena.

A. Carpinteri, A. Manuello  An indirect evidence of piezonuclear fission reactions: Geomechanical and geochemical evolution in the Earth's crust // Физ. мезомех. - 2012. - Т. 15. - № 2. - С. 51-60