Li-F花岗岩液态分离的稀土地球化学标志

The geochemical indicatrixes of the REE in Li F granite liquid segregation.

华南和其他国家典型Ｌｉ－Ｆ花岗岩的１１８个稀土分析研究表明，随Ｌｉ－Ｆ花岗岩由早至晚阶段或自下而上不同岩相演化，稀土模式曲线有三种变化类型：①降低变化，②升高变化，③突然变化等类型。①称为正向演化类型，是结晶分异结果；②称为反向演化类型，代表气液分馏为主的液态分离；③称为演化突变类型，是不混溶为主的液态分离形成。因此，不混溶为主的液态分离标志是稀土模式演化突变类型和Ｌｉ－Ｆ花岗岩在ＲＥＥ－（Ｌａ／Ｙｂ）ｎ、Ｌａ／Ｓｍ－Ｌａ（μｇ／ｇ）图解中主演化方向线与次演化方向线或与成分点呈分离特点。气液分馏为主的液态分离标志是稀土模式反向演化类型和Ｌｉ－Ｆ花岗岩在ＲＥＥ－（Ｌａ／Ｙｂ）ｎ、Ｌａ／Ｓｍ－Ｌａ（μｇ／ｇ）图解中主演化方向线。

The results of 118 REE analyses of Li F granites from South China and other countries indicate that there are three variation types of REE model curves with the different evolution from early to late stages of Li F grantie complex or from lower to upper petrofacies of the Li F granite body, which are (1) decreasing,(2) increasing and (3) saltatory variation types The first variation type is called positive evolution type, which is the production of crystallization differentiation The second variation type is called reversion evolution type, which represents the liquid segregation mainly with vapour liquid fractional distillation The third variation type is called saltatory variation type, which is formed from the liquid segregation mainly with immiscibility Therefore, the indicatrixes of the liquid segregation mainly with immiscibility are the saltatory variation type of REE model evolution and the separative feature of main evolution trend line either with sub evolution trend line or with composition point of Li F granites in the diagrams of REE (La/Yb) n and La/Sm La The indicatrixes of the liquid segregation with vapour liquid fractional distillation are the reversion evolution type of REE model curves and the main evolution trend line of Li F granites is directional to the right upper part of the diagrams of REE (La/Yb) n and La/Sm La