WATER-ROCK INTERACTION Technique

The water-rock experimental laboratory employs inert gold reaction cells to study complex highly corrosive liquid-vapor-solid systems at extremes of redox and pH, and from sedimentary to metamorphic conditions. The lab was originally designed to study seawater-basalt interaction, which takes place deep within seafloor geothermal systems and gives rise to Black Smokers. The technique has been applied to a range of systems, including: Scaling processes in waste water injection wells The physical chemistry of simple systems such as NaCl-H2O The study of aqueous organic reactions The equipment was designed for serial on-line sampling of complex liquid-vapor-solid systems under any conditions of temperature and pressure up to 500° and 500 bars pressure without disturbing temperature or pressure. This eliminates time delays and other problems associated with quenching. Samples are taken in gas-tight syringes from the sample valve, filtered (0.2 micrometers) and divided into several aliquots for complete major/minor component analyses as follows: pH and total dissolved sulfide (sum of H2S) are analyzed by electrode, total dissolved CO2 is measured by infrared analyzer H2 and CH3 by gas chromatograph Cl by titration-chloridometer SO4 by ion chromatograph Si, Na, K, Mg, Ca, Fe, Mn, Ni, Cu, Mo, B, Ba, Ti, P, and Zn by inductively-coupled plasma spectroscopy

| Capabilities | | Chemical Analyses  |

URL http://geology.cr.usgs.gov/capabilities/chema/watrock/tech.html