2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 18
Presentation Time: 8:00 AM-4:45 PM

Do Crooked Crystals of Orthoclase from Papoose Flat Pluton Tell Truth about Replacement by Cycling Excess Energies in Coupled Dissolution and Precipitation?

DICKSON, F.W., Department of Geological Sciences, University of Nevada, Reno, NV 89557, 110 East Sky Ranch Blvd, Sparks, 89441, fdickson@mines.unr.edu

Replacement products range from local mineral assemblages to massive granitic bodies. Replacement under stress occurred in Papoose Flat pluton, California, near close of emplacement. Excess energy of stress perturbed minerals at surfaces and induced growth of crystals of orthoclase and quartz by simultaneous dissolution and precipitation, under metamorphic conditions akin to those of augen gneiss (Dickson, 1996, 2000). Internal textures of whole crystals viewed in chosen orientations were correlated Shapes of crystals depart from monoclinic and are crooked to the eye, some are rounded. Concentric layers oscillating in Ba/K ratios are parallel to outer shapes from centers to margins, showing they grew during stress (Ortoleva, 1994). Shapes and charge distributions of atoms differ for each face of sector volumes, in which are preferentially concentrated tiny oriented minerals (hour glasses)that occur as larger grains in pluton. Reactions with finite rates require departure from equilibrium, close to which is treated by Onsager (1931,1932); and far from which by experiments and theories of Prigogine (1997). Excess energy drives reactions that follow paths chosen by nature. Reaction cells transport mass and energy in earth by cycling excess energies of liquefaction between endothermic and exothermic reactions (Dickson, 2000, 2005). Country rocks dissolve at tops, minerals precipitate at bases. Released energy migrates upward by convective overturn. Volcanoes and intrusive bodies are emplaced. Granites contain as much as 50% crustal constituents. Volcanoes differ in compositions in successive eruptions. Variations in compositions result from reactions of liquids with surroundings.