二氧化钛-水体系氧同位素分馏系数的实验研究

对TiO2的两种常见同质多像变体金红石和锐钛矿与水之间的氧同位素分馈系数的实验研究进行了系统的总结和评述。水热品化法（575～775℃）和水热氧化法（300～700℃）以及低温水解（22～50℃）获得的实验金红石－水体系分馏系数与增量方法理论计算结果相一致。低温水对法获得的锐钛矿－水体系分馏可能是一种不平衡分馏，其分馏系数的大小决定于锐钛矿的形成机制。同时，低温水解实验还揭示．在低温矿物形成和同质多像转变过程中可能存在氧同位素继承性，这对解释低温环境氧同位素数据具有重要的地球化学意义。

EXPERIMENTAL STUDIES OF OXYGEN ISOTOPE FRACTIONATION FACTOR BETWEEN TITANIUM DIOXIDE AND WATER

The experimental studies of oxygen isotope fractionation between rutile or anatase, which are the two common polymorphs of TiO2, and water are systematically reviewed. The results for the rutile water system derived from the hydrothermal crystallization (575 ~ 775℃), hydrothermal oxidization (300~700℃ ) and low-temperature hydrolysis (22 ~ 50℃ ) methods are in good agreement with the　theoretical calculations obtained by means of the increment method. The oxygen isotope fractionations between anatase and water obtained by the fow-temperature hydrolysis method are in diequilibrium,and the variation of fractionation values depends on the formation mechanisms of anatase. The lowtemperature hydrolysis experimental results revealed that there would be an oxygen isotope inheritance in mineral formation and polymorphism. The studies are of gaxhemical sboificance in interpreting the oxygen data for low-temperature geological environments.