The partitioning of a large suite of trace elements between biotite and water-saturated granitic melt was measured at 2 kbar and 700—800 ˚C. To reach equilibrium and to grow biotite crystals large enough for analysis, runs usually lasted from 30 to 45 days. In every charge, a few trace elements were initially doped at the 0.1—0.5 wt. % level and analyzed by electron microprobe after the run. First-row transition metal ions are highly compatible in biotite with D^biotite/melt of 17 for Ti, 35 for V, 47 for Co, 174 for Ni, and 5.8 for Zn. A very notable exception is Cu with D^biotite/melt < 0.9. This is likely one of the reasons why Cu is enriched together with Mo (D^biotite/melt = 0.29) in porphyry deposits associated with intermediate to felsic plutons, while the other transition metals are not. Both Nb and Ta are mildly compatible in biotite with D^biotite/melt being larger for Nb (3.69) than for Ta (1.89). Moderate (15—30%) biotite fractionation would be sufficient to reduce the Nb/Ta ratio from the chondritic value to the range observed in the continental crust. Moreover, the strong partitioning of Ti into biotite implies that already modest biotite fractionation suppresses the saturation of Ti-oxide phases and thereby indirectly facilitates the enrichment of Ta over Nb in the residual melt. The heavy alkalis, alkaline earths, and Pb are only mildly fractionated between biotite and melt (D^biotite/melt = 3.8 for Rb, 0.6 for Cs, 0.6 for Sr, 1.8 for Ba, 0.7 for Pb). The rare earth elements are generally incompatible in biotite, with a minimum for D^biotite/melt of 0.03–0.06 at Gd, Tb, and Dy, while both the light and heavy rare earths are less incompatible (e.g. D^biotite/melt = 0.6 for La and 0.3 for Yb). This behavior probably reflects a partitioning into two sites, the K site for the light rare earths and the octahedral Mg site for the heavy rare earths. There is no obvious dependence of the rare earth partition coefficients on tetrahedral Al in the biotite, presumably because charge balancing by cation vacancies is possible. Allanite was found as run product in some experiments. For the light rare earths, D^{allanite/melt} is very high (e.g. 385 to 963 for Ce and Nd) and appears to increase with decreasing temperatures. However, the rather high solubility of allanite in the melts implies that it likely only crystallizes during the last stages of cooling of most magmas, except if the source magma is unusually enriched in rare earths.

在 2 kbar 和 700-800 ˚C 下测量了大量微量元素在黑云母和水饱和花岗岩熔体之间的分配。为了达到平衡并生长足够大的黑云母晶体以进行分析，运行通常持续 30 到 45 天。在每次充电中，最初以 0.1-0.5 重量％掺杂少量微量元素。% 水平并在运行后通过电子微探针进行分析。第一排过渡金属离子在黑云母中与 D^{黑云母/熔体}高度相容，Ti 为 17，V 为 35，Co 为 47，Ni 为 174，Zn 为 5.8。一个非常值得注意的例外是 Cu，D^{黑云母/熔体} < 0.9。这可能是 Cu 与 Mo（D^{黑云母/熔体）}一起富集的原因之一 = 0.29) 在与中长英质岩体相关的斑岩矿床中，而其他过渡金属则不然。Nb 和 Ta 在黑云母中都温和相容，D^{黑云母/熔体}对于 Nb (3.69) 比对于 Ta (1.89) 大。中等 (15-30%) 黑云母分馏足以将 Nb/Ta 比值从球粒陨石值降低到在大陆地壳中观察到的范围。此外，Ti 强烈分配到黑云母中意味着已经适度的黑云母分馏抑制了 Ti 氧化物相的饱和，从而间接促进了残余熔体中 Ta 富集 Nb。重碱金属、碱土金属和铅在黑云母和熔体之间仅轻度分馏（D^{黑云母/熔体} = Rb 3.8，Cs 0.6，Sr 0.6，Ba 1.8，Pb 0.7）。稀土元素在黑云母中通常不相容，在 Gd、Tb 和 Dy 中，D^{黑云母/熔体}的最小值为0.03–0.06，而轻稀土和重稀土的不相容程度较低（例如 D^{黑云母/熔体} = 0.6 La 和 Yb 为 0.3）。这种行为可能反映了分成两个位点，轻稀土的 K 位和重稀土的八面体 Mg 位。稀土分配系数对黑云母中的四面体铝没有明显的依赖性，大概是因为阳离子空位的电荷平衡是可能的。在一些实验中发现Allanite作为运行产品。对于轻稀土，D ^{allanite/melt}非常高（例如，Ce 和 Nd 为 385 到 963）并且似乎随着温度的降低而增加。然而，岩浆在熔体中相当高的溶解度意味着它可能只在大多数岩浆冷却的最后阶段结晶，除非源岩浆异常富含稀土。