Tests of isotopic equilibrium

Tats of isotopic One of the merits of oxygen isotope thermometry is that there are potentially a equilibrium large number of thermometers available in a single rock, a situation which rarely arises with cation-exchange thermometers. This allows the assumption of isotopic equilibrium to be tested. 

It should be noted, however, that the difference in temperatures of equilibration is only one reason for isotopic disequilibrium and isotopic exchange with an externally derived fluid is an equally possible explanation. This may be assessed on a plot of 5-values for two coexisting minerals. Equilibrium is measured relative to a straight line with a slope of 45 which represents a A value for the mineral-pair 

Applications There are both low-temperature and high-temperature applications of oxygen isotope thermometry. 

The method assumes that the mq gen isotopic composition of seawater was the same in the past as today, an assumption which has frequently been challenged and which does not hold for at least parts of the Pleistocene when glaciation removed / 0-depleted water from the oceans. This has the effect of amplifying the temperature variations (Clayton, 1981). The method also assumes that the isotopic 

Low-temperature isotopic thermometry is also applicable to ascertaining the temperatures of diagenesis and low-grade metamorphism, and estimating the temperatures of active geothermal systems, both in the condnental crust and on the ocean floor. 

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