Affiliations: Politecnico di Torino, Department of Structural Engineering and Geotechnics, Torino, Italy | Istituto Nazionale di Fisica Nucleare, Torino, Italy
Note:  Address for correspondence: A. Carpinteri, Politecnico di Torino, Department of Structural Engineering and Geotechnics, Corso Duca degli Abruzzi 24, 10129 Torino, Italy. E-mail: [email protected]
Abstract: Neutron emission measurements, by means of 3He devices and neutron bubble detectors, were performed during three different kinds of compression tests on brittle rocks: (i) under displacement control, (ii) under cyclic loading and (iii) by ultrasonic vibration. The material used for the tests was Green Luserna Granite. Since the analyzed material contains iron, our conjecture is that piezonuclear fission reactions involving fission of iron into aluminum, or into magnesium and silicon, should have occurred during compression damage and failure. This hypothesis is confirmed by Energy Dispersive X-ray Spectroscopy (EDS) tests conducted on Luserna Granite specimens. It is also interesting to emphasize that the present natural abundances of aluminum (≈8%), and silicon (28%) and scarcity of iron (≈4%) in the continental Earth's crust should be possibly due to the piezonuclear fission reactions considered above.
Keywords: Neutron emission, piezonuclear reactions, rocks crushing failure, energy dispersive X-ray spectroscopy, plate tectonics, element evolution