Open-system exchange isotopic ratios

In conclusion, fluid-rock ratios should be used for a rough calculation to demonstrate open or closed system behavior. These ratios can yield qualitative information on stable isotope fluid-rock exchange. Their use should be limited to cases where continuum mechanics approaches to stable isotope transport are not applicable. This is often the case when field relations do not provide evidence of the geometry of the flow system. But one should keep in mind while interpreting the data, that the values do not correspond to actual, physical fluid amounts, but just represent a measurement of exchange (reaction) progress. 

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