Modeling Tools for Geochemistry

Interactive calculators for carbonate chemistry, charge-balance checking, and mineral-oxide conversions. Everything runs locally in your browser.

Open Carbonate System

Equilibrium speciation in fresh waters. Two views: a 3-input graph view (T, pCO₂, TA) and the full 11-input table view that takes major ion compositions and returns species, saturation indices, and bulk parameters.

Seawater Carbonate System

Solve the open seawater carbonate system from any two parameters of {TA, DIC, pH, pCO₂}. Returns full speciation plus saturation states for calcite and aragonite.

Charge Balance

Verify a major-ion analysis for electrical neutrality and flag errors outside ±5 %.

XRF Oxide Simulator

Convert any mineral formula into theoretical XRF oxide weight fractions. Includes a searchable index of ~5700 RRUFF minerals.

Mineral Dissolution (Lasaga)

Lifetime of a spherical crystal at pH 5, 25 °C, using the Lasaga (1994) dissolution rate compilation.

Forsterite Dissolution f(pH, T, r)

Dissolution lifetime of a forsterite crystal as a function of pH, temperature and initial radius (Rimstidt et al. 2012).

Bjerrum Plot Explorer

Speciation fractions vs pH for carbonic acid and several organic acids.

DIC vs pCO₂

DIC as a function of atmospheric pCO₂ for total alkalinities from 0 to 50 mmol / kg.