雪球结构的产出特征、钠长石电子探针分析及其它间接证据都说明 ,雪球结构是在岩浆结晶过程中形成的。雪球结构形成与否主要与岩浆熔体中 Na2 O/ K2 O比值和 F、H2 O含量有关。较大的 Na2 O/ K2 O比值 ( >1)使钠长石首先从熔体中晶出 ;较高的 F含量使岩浆固相线温度大大降低 ,有利于岩浆分异演化并形成接近端员组分的钠长石和钾长石 ;较高的 H2 O含量有利于石英以较快的速度生长并逐渐包裹钠长石形成雪球结构。自形的 α-石英斑晶、接近各自端员组分的钾长石和钠长石等说明该类花岗岩形成温度较低。众多的地质、地球化学依据都证明了 ,华南富锂氟含稀有金属花岗岩是从过铝富氟富钠的残余熔体中直接结晶而成的。 The output characteristics of the snowball structure, the analysis of albite electron microprobe, and other indirect evidence suggest that the snowball structure was formed during the magma crystallization process. The formation of snowball structure is mainly related to the ratio of Na2 O / K2 O and the content of F and H2 O in the magma melt. The larger Na 2 O / K 2 O ratio (> 1) causes albite to crystallize out of the melt first. The higher F content greatly decreases the magmatic solidus temperature, which is favorable for the differentiation of magma and the formation of a close to the terminal staff Composition of albite and potassium feldspar; higher content of H 2 O is conducive to the rapid growth of quartz and gradually wrapped albite formation of snowball structure. The self-shaped α-quartz porphyrites, potash feldspar and albite close to their end-member composition indicate that the formation of this type of granite is of lower temperature. Numerous geologic and geochemical evidences prove that South China-rich lithium-bearing rare-metal granites are crystallized directly from the residual melt of perfluorite-enriched sodium fluoride.