Geochemical indicators of subsurface temperature: Part 1, basic assumptions

R.O. Fournier; D. E. White; A. H. Truesdell

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Geochemical indicators of subsurface temperature: Part 1, basic assumptions

R.O. Fournier·D. E. White·A. H. Truesdell

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Abstract

The chemical and isotopic compositions of hot-spring water and gas are used to estimate subsurface temperatures. The basic assumptions inherent in the methods are seldom stipulated. These assumptions include (1) a temperature-dependent reaction at depth, (2) a supply of the solid phase involved in the reaction to permit saturation of the constituent used for geothermometry, (3) water-rock equilibrium at depth, (4) negligible re-equilibration as the water flows to the surface, and (5) no dilution or mixing of hot and cold water. The first three assumptions are probably good for a few reactions that occur in many places. The last two assumptions probably are not valid for many hot-spring systems; information obtained is therefore for the shallower parts of those systems, or a limiting temperature (generally a minimum) is indicated.

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R.O. Fournier, D. E. White, A. H. Truesdell. 1974. Geochemical indicators of subsurface temperature: Part 1, basic assumptions. https://pubs.usgs.gov/publication/70232438

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