Paper No. 1
Presentation Time: 8:00 AM-5:00 PM
DISEQUILIBRIA, SOLUTIONS, CHEMICAL EVOLUTION OF EARTH: ENRICHMENT OF CRUST IN RHYOLITIC AND GRANITIC COMPONENTS
Large volumes of rhyolite and granites in continents can not be derived by Bowen-style differentiation. Earth is an open system in which Prigogine's disequilibria prevail. Magmas are chemical solutions (Dickson and Hsu). Solubilities of phases are functions of Gibbs' chemical potentials, which depend on temperature (T), pressure (P), and concentration (X), TPX. Reactions with finite rates are time (t) dependent and are functions of (TPXt), as confirmed by Prigogine's experiments. Granites do not occur in ocean basins. Local, relatively rapid, near-surface processes account for small volumes of rhyolitic magma at Hawaiian basaltic volcanoes. Lengthy, regional, deep-seated processes generate rhyolites and granites. Rocks liquefy when energies exceed equilibrium, as at leading edges of descending slabs. Liquid coatings preferentially absorb fugitive (granitic) components. Magmas expend excess energy of liquefaction in solidification. Deep bodies do not loose much heat. They respond to gradients in TPX and gravity and move as diapirs and chemically by reaction cells (Dickson). Granitic components are preferentially absorbed. Energies cycle in endothermic dissolution of cover rocks and exothermic crystallization at bases. Energy moves up by convection in central liquids. Disequilibrium partial dissolution reactions differentiate the earth and generate rhyolitic-granitic compositions. Prigogine, 1997; Dickson and Hsu, 2000; Dickson, 2000..