THE SYSTEM CO2-N-2 AT HIGH-PRESSURE AND APPLICATIONS TO FLUID INCLUSIONS

Postulated fluid-fluid immiscibility of 50-50% CO2-N-2 mixtures has be en checked by high-pressure experiments (<5 GPa; <400 K) and could be rejected. The implications for the interpretation of high-density flui d inclusions (<42 cm(3)/mole) in eclogite and granulite-facies rocks a re discussed: only models based on LG-immiscibility are applicable for molar volume calculations also in the very-high-pressure range. The p osition of the critical curve for CO2-N-2 could be more accurately det ermined with the help of experimental and fluid inclusion data. The S- 2-F isopleth and the three-phase (S1S2F) line have been established fo r 50.6% N-2 composition. Copyright (C) 1998 Elsevier Science Ltd.