Oxygen isotopic transport and exchange during fluid flow: One-dimensional models and applications

Journal Article · Sat Jan 01 00:00:00 EST 1994 · American Journal of Science; (United States)

DOI:https://doi.org/10.2475/ajs.294.1.1· OSTI ID:6924604

Bowman, J R ^[1]; Willett, S D ^[2]; Cook, S J ^[3]

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1. Univ. of Utah, Salt Lake City, UT (United States)
2. Dalhousie Univ., Halifax, Nova Scotia (Canada)
3. Univ. of Utah, Salt Lake City, UT (United States) Environ Corp., Houston, TX (United States)

In this work the authors investigate the consequences of fluid flow and fluid-rock interaction to the isotopic evolution of fluids and rock with one-dimensional transport models of fluid flow and oxygen isotope exchange. Transport models dealing with stable isotopes are well established in recent geochemical literature. The authors extend previous treatments by presenting the derivation of both analytical and numerical solutions to the transport equations incorporating simultaneously advection, diffusion and hydrodynamic dispersion, and kinetics of isotopic exchange. The increased generality of numerical solutions allows the incorporation of other effects which control the spatial patterns of [delta][sup 18]O values developed in rocks and fluids including multiple reactive species and temperature gradients. The authors discuss the effects of flow parameters, conditions of isotopic exchange, and temperature gradients on the spatial patterns of isotopic shifts produced in rock sequences subjected to fluid flow, and on conventionally calculated W/R ratios for these rock sequences. Finally, the authors examine the implications of oxygen isotope transport for two natural systems where isotopic shifts or gradients could be interpreted in terms of unidirectional fluid infiltration. Solutions of one-dimensional transport equations including the mechanisms of advection, diffusion, hydrodynamic dispersion, and non-equilibrium exchange between water and rock indicate that the time-space evolution of oxygen isotopic compositions of rock and infiltrating fluid is dependent on (1) the rate of fluid infiltration, (2) the diffusive and dispersive properties of the rock matrix, (3) the rate of isotopic exchange, and (4) the rock-water mass oxygen ratio in a unit volume of water-saturated, porous rock. 56 refs., 18 figs., 2 tabs.

• OSTI ID: 6924604
• Journal Information: American Journal of Science; (United States), Vol. 294:1; ISSN 0002-9599
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
15 GEOTHERMAL ENERGY
EARTH CRUST
FLUID FLOW
ONE-DIMENSIONAL CALCULATIONS
ISOTOPIC EXCHANGE
GEOLOGY
HYDRODYNAMICS
OXYGEN 18
PERMEABILITY
TRANSPORT THEORY
EVEN-EVEN NUCLEI
FLUID MECHANICS
ISOTOPES
LIGHT NUCLEI
MECHANICS
NUCLEI
OXYGEN ISOTOPES
STABLE ISOTOPES
580000* - Geosciences
150200 - Geology & Hydrology of Geothermal Systems