Electric charge carriers in crustal rocks and what they may tell us about the Solid Earth
published: Jan 1, 2003
Open Access (paper can be downloaded for free)
There is strong evidence that igneous and high-grade metamorphic rocks contain relatively highly densities (- 10 20 per cubic centimeter) of dormant electronic charge carriers in form of positive hole pairs (PHP). A positive hole is a defect electron residing in the O 2p-dominated valence band of (otherwise insulating) silicate minerals. Therefore, a positive hole is an O- in a matrix of O2-. In the language of chemistry a PHP is a peroxy bond, -OO-, probably linking two adjacent SiO4 tetrahedra.