In order to elucidate the kinetic partitioning of cations between olivine and basalt, we performed undercooling (−ΔT) and cooling rate (CR) experiments at atmospheric pressure and QFM-2 buffer. Starting from the superliquidus temperature of 1250 °C, a Hawaiian tholeiitic basalt was cooled at the rates of 4 (CR4), 20 (CR20), and 60 (CR60) °C/h to the final target temperatures of 1175 °C (−ΔT = 35 °C; −ΔT35) and 1125 °C (−ΔT = 85 °C; −ΔT85). Results show that polyhedral olivine morphologies are obtained at -ΔT35, whereas strong disequilibrium skeletal and/or dendritic textures form at -ΔT85. The amount of forsterite in olivine decreases from to 85% to 78% with increasing both -ΔT and CR. A diffusive boundary layer also develops in the melt next to the olivine surface and its composition becomes progressively enriched in Ca, owing to its incompatible behavior with the lattice site. Residual melts are progressively depleted in silica and enriched in alkali from CR4 to CR60, but silica-rich melts are observed with increasing -ΔT. In terms of Fe²⁺-Mg exchange, olivines obtained at -ΔT35 are always in equilibrium with the diffusive boundary layer, comprising both the interface melt next to the olivine surface and the far-field melt where all chemical gradients cease. At -ΔT85, however, the Fe²⁺-Mg exchange indicates two distinct equilibration stages between olivine core and far-field melt, and between olivine rim and interface melt. Partition coefficients (Kd) of Mg, Fe, Mn, Ca, and Cr calculated at the olivine-melt interface preferentially change as a function of -ΔT rather than CR. From -ΔT35 to -ΔT85, Kd_Mg, Kd_Fe, Kd_Mn, and Kd_Cr remarkably increase, whereas the opposite applies to Kd_Ca. Through the application of equilibrium partitioning models, we found that Mg, Fe, Mn, and Ca are incorporated into the olivine lattice site at near-equilibrium proportions. This generally good agreement with modeling data demonstrates that diffusive mass transport of cations in our experiments occurred under the conditions of local equilibrium at the olivine surface. In contrast, marked deviations from the expected equilibrium are found for K_Cr in response to the major influence of crystal field stabilization energy on cation incorporation.

为了阐明橄榄石和玄武岩之间阳离子的动力学分配，我们在大气压和 QFM-2 缓冲液下进行了过冷 ( -ΔT ) 和冷却速率 ( CR ) 实验。从超液相线温度 1250 °C 开始，夏威夷拉斑玄武岩以 4 ( CR4 )、20 ( CR20 ) 和 60 ( CR60 ) °C/h的速率冷却至最终目标温度 1175 °C ( - ΔT  = 35 °C；-ΔT 35) 和 1125 °C ( -ΔT  = 85 °C；-ΔT 85)。结果表明，在-ΔT处获得了多面体橄榄石形貌35，而在-ΔT 85处形成强烈的不平衡骨架和/或树枝状结构。橄榄石中镁橄榄石的量随着-ΔT和CR 的增加而从85% 减少到78% 。在橄榄石表面附近的熔体中也会形成扩散边界层，并且由于其与晶格位点的不相容行为，其成分逐渐富含 Ca。从CR4到CR60，残余熔体逐渐耗尽二氧化硅并富含碱，但随着-ΔT 的增加，观察到富含二氧化硅的熔体。在 Fe ²⁺ -Mg 交换方面，在-ΔT下获得的橄榄石35 总是与扩散边界层平衡，包括靠近橄榄石表面的界面熔体和所有化学梯度停止的远场熔体。然而，在-ΔT 85 处，Fe ²⁺ -Mg 交换表明橄榄石核心和远场熔体之间以及橄榄石边缘和界面熔体之间存在两个不同的平衡阶段。在橄榄石-熔体界面计算的 Mg、Fe、Mn、Ca 和 Cr 的分配系数 (Kd) 优先随-ΔT而不是CR 变化。从-ΔT35到-ΔT85，Kd _Mg、Kd _Fe、Kd _Mn和 Kd _Cr显着增加，而 Kd _Ca则相反。通过平衡分配模型的应用，我们发现 Mg、Fe、Mn 和 Ca 以接近平衡的比例结合到橄榄石晶格位点中。这种与建模数据总体上很好的一致性表明，我们实验中阳离子的扩散传质发生在橄榄石表面的局部平衡条件下。相比之下，由于晶体场稳定能对阳离子掺入的主要影响，K _Cr发现了与预期平衡的显着偏差。