Original paper
Nanoscale phase equilibrium in a triggered lightning-strike experiment
Rietmeijer, Frans J.M.; Karner, Jim M.; Nuth, Joseph A.; Wasilewski, Peter J.
European Journal of Mineralogy Volume 11 Number 1 (1999), p. 181 - 186
23 references
published: Feb 11, 1999
manuscript accepted: Aug 19, 1998
manuscript received: Apr 3, 1998
Abstract
Abstract We describe the nanometer-sized phases in millimeter-sized spheres produced in a triggered lightning-strike experiment characterized by ultra-high heating of ~ 108 degrees s-1 followed by similarly rapid quenching. The compositions of the aluminosilica glass spheres define a metastable Al2O3-SiO2 eutectic at ~ 40 wt. % A1203. The other phases are defined by the liquidus in the SiO2-Al2O3-Fe3O4 (wt %) phase diagram whereby hercynite formed at ~ 1750°C and domains of Fe3+-rich cordierite glass that represent a ternary minimum melt at ~ 1400°C with cotectic glasses linking this glass and spinel. Metastable eutectics are potentially important to understand the phase relationships due to flash heating events.
Keywords
pyrometamorphism • fulgurites • triggered lightning experiment • experimental petrology • metastable equilibrium • mineralogy • analytical electron microscopy