含水中基性大陆下地壳部分熔融能形成C型埃达克岩吗?——与张超等商榷

Can Partial Melting of the Hydrous Intermediate-Basic Lower Continental Crust Generate C-type Adakites?——Comment on Zhang et al. (2012)

中基性（SiO2=50％～60％）成分源岩在中等压力（p=1．0～1．2GPa，相当于35～40km）下的失水部分熔融残留相中斜长石比例大，而石榴子石的比例不超过20％，与之平衡的中酸性熔体难以具备埃达克岩的地球化学特征。富钾源岩部分熔融体系中钾的地球化学行为不遵循稀溶液的Henry定律，基于强不相容假设的模拟计算很可能会过高估计熔体中的钾含量。

Dehydration melting of the intermediate-basic （SiO2=50%-60%） source undera pressure of 1.0-1.2 GPa （corresponding to 35-40 km depth） will generate high portion of plagioclase in the residuum, and the content of garnet in the residuum may not exceed 20% in most instances. Accordingly, the intermediate to acid melts, which are in equilibrium with such residuum, will not display the geochemical features of adakite. Meanwhile, the geochemical behavior of potassium in the partial melting system of K-rich sources does not obey the Henry＇s law of dilute solution, so the potassium content in the melt might be significantly overestimated by the calculation based on the assumption of the highly incompatible behaviour of potassium.