The Mushgai-Khudag complex is part of the Late Mesozoic Central Asian carbonatite province. Fluorite mineralization is manifested throughout the province, including the Mushgai-Khudag complex. We have investigated the geochemical features and fluid inclusions of fluorites from different types of fluorite-bearing rocks. Fluorite from quartz-fluorite rocks has rare earth element (REE) concentrations in the range of 10500−144300 ppm and the highest light REE contents, with (La/Yb)_N = 56−960. Fluorite from the fluorite-apatite-celestine rocks has slightly lower REE enrichment, especially light REE content, with concentrations of 200−5900 ppm and (La/Yb)_N = 18−204. Fluorite from the fluorite-calcite rocks is characterized by REE contents of 22−1100 ppm and a variable (La/Yb)_N of 0.6−59. These variations in the fluorite REE composition from different types of rocks were probably caused by the fact that at elevated temperatures, fluorine-containing light REE complexes are more stable than fluorine-containing heavy REE complexes. The progressive enrichment of medium and heavy REEs in the latter fluorite is related to fluid evolution. The homogenization temperature and salinity values of fluid inclusions in the Mushgai-Khudag fluorites vary between 550 and 185 °C and from rather high to 2 wt.%, respectively. The parental fluids of the fluorite-bearing rocks evolved from quartz-fluorite rocks to fluorite-apatite-celestine rocks to fluorite-calcite rocks. The key component was changed from sulfate to carbonate-chloride along with the high to medium temperature decrease (∼500−245 °C).

Mushgai-Khudag复合体是中生代晚期中亚碳酸盐岩省的一部分。萤石矿化在全省都有体现，包括Mushgai-Khudag复合体。我们研究了不同类型的含萤石的岩石的萤石的地球化学特征和流体包裹体。来自石英萤石岩的萤石的稀土元素（REE）浓度在10500-144300 ppm范围内，并且轻稀土元素含量最高，（La / Yb）_N = 56-960。萤石-磷灰石-天青石岩石中的萤石具有较低的稀土元素富集，特别是轻稀土元素含量，浓度为200-5900 ppm，（La / Yb）_N = 18-204。萤石-方解石岩石中的萤石的特征是REE含量为22-1100 ppm，_N（La / Yb）可变为0.6-59。来自不同类型岩石的萤石REE组成的这些变化可能是由于以下事实造成的：在高温下，含氟轻REE配合物比含氟重REE配合物更稳定。后者萤石中中等和重稀土元素的逐步富集与流体演化有关。Mushgai-Khudag萤石中流体夹杂物的均质温度和盐度值在550至185°C之间变化，并且分别从相当高到2 wt。％。含萤石的母体流体从石英萤石到萤石-磷灰石-天青石到萤石-方解石。随着高温到中温下降（〜500-245°C），关键成分从硫酸盐变为碳酸盐-氯化物。