NETPATH

An interactive program for calculating NET geochemical reactions and radiocarbon dating along a flow PATH

NETPATH is an interactive program for modeling net geochemical mass-balance reactions between an initial and final water along a hydrologic flow path. Alternatively, NETPATH computes the mixing proportion of two initial waters and net geochemical reactions that can account for the observed composition of a final water. The program utilizes previously defined chemical and isotopic data for waters from a hydrochemical system. The calculations are of use in interpreting geochemical reactions, mixing proportions, evaporation and (or) dilution of waters, and mineral mass transfer in the chemical and isotopic evolution of natural and environmental waters.

A mass-balance model is defined as the masses (per kilogram H2O) of a set of plausible minerals and gases that must enter or leave the initial solution in order to define exactly a set of selected elemental, electron transfer, and isotopic constraints observed in a final (evolutionary) water. In hydrochemical systems the number of reacting phases is often larger than the number of constraints necessary to define their composition. The processes of dissolution, precipitation, ion exchange, oxidation/reduction, degradation of organic compounds, incongruent reaction, gas exchange, mixing, evaporation, dilution, isotope fractionation, and isotope exchange can be considered. Geochemical mass-balance reaction models are examined between selected evolutionary waters for every possible combination of the plausible phases that account for the composition of a selected set of chemical and isotopic constraints in the system.

NETPATH solves a set of linear equations that account for conservation of mass, and (optionally) conservation of electrons and selected isotopes to find every subset of the selected phases (every model) that satisfies the chosen constraints. Each mass balance model can be treated as an isotope evolution problem solving isotope mass balance and Rayleigh distillation problems to predict the isotopic composition at the final point on the flow path.

SYSTEM REQUIREMENTS Intel 80i86 based computer, 640 Kb RAM, DOS 3.0 or higher; math coprocessor optional.

CLICK HERE TO DOWNLOAD - as DOS files

Developers: L.N. Plummer, E.C. Prestemon, and D.L. Parkhurst (U.S. Geological Survey)