Role of liquids in disequilibrium processes of earth and replacement in Papoose Flat pluton, California


Liquids play important roles in chemical and physical processes in earth. Natural
liquids are solutions from which phases separate by solubilities as functions of temperature,
pressure and concentrations. Liquid bodies with excess energy react with
enclosing rocks. Solubilities of minerals in magmas are functions of T and P. Reactions
in liquid columns adjust to pressure gradients. Mass and energy migrate in open
systems of earth by disequilibrium processes fluxed by liquids. Processes driven by
energy in excess along gradients of temperature (T) pressure (P) are affected by
electromagnetic and gravitational fields. Interstitial fluids increase ductility of rocks,
making possible convective overturn in vertical thermal gradients. Excess energies of
liquefaction move in floating diapirs and in reaction cells that replace country rocks.
Rocks liquefy where input of excess energy exceeds diffusive heat loss, as along
descending plates. Grains coat with fluids of most soluble components and build into
magma bodies with excess energies of liquefaction, which must be expended in solidifying.
On and near surface diapirs loose excess energy from reactions with adjacent
rocks and heat loss. Deep magma bodies near local TPX conditions can not quench.
They float as diapirs along tectonic paths or migrate chemically in reaction cells, which
endothermically dissolve cover rocks and exothermically crystallize minerals at bases.
Energies released at bases of cells rise by convective overturn in central liquids. Chemical
compositions of reaction cells drive toward granitic. Repeated transit of reaction
cells play roles in converting the original crust to the present granitic crust.
Volcanoes eject materials of differing compositions during and between eruptions.
Magmatic liquids react with container rocks and mix with newly arrived liquids.
Openings to surface, along paths of dissolution and fractures, are facilitated by
increased vapor pressures.
Liquids are important in replacement, which operates at all scales, under wide
TPX conditions in diverse geologic environments. Replacement results from disequilibrium
reactions in open systems of earth, with rates increased by liquids. Reactions
that form ore deposits depart from equilibrium and commonly involve replacement.
At Papoose Flat, California, megacrysts of orthoclase and quartz replaced igneous
minerals coated by fluids in a newly crystallized pluton. Excess energies of stress
cycled between dissolving host minerals and crystallizing new phases. Interstitial
liquids were paths for diffusion of components.
Origin of granite by replacement satisfies energy and room requirements and
accounts for major contents of granites of crustal constituents, their transgressive,
crosscutting contacts with country rocks, and passivity.

SKU: 2005-12 Category:

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Primary Author

F.W. Dickson