Abstract Among the Apollo returned samples were basaltic rocks belonging to the KREEP suite, which are thought to have been erupted ~4.1–3.9 ​Ga via dike propagation from the residual magmatic layer residing below the lunar crust as the last part of the solidifying lunar magma ocean. The emplacement dynamics of KREEP magma reaching the lunar surface are generally poorly understood, in part because no rheological data are available to model the conditions of KREEP ascent in detail, even ~50 years after KREEP basalt discovery. This study provides the first rheological data for KREEP magmas, as a function of temperature and crystal content, from the liquidus temperature (~1205 ​°C) to ~16% crystals by volume at ~1177 ​°C. The lava’s rheological behavior becomes non-Newtonian at just a few degrees of cooling below the liquidus and is well represented by a shear-thinning power-law equation. We applied these data to a buoyancy-driven dike ascent model, suggesting that if KREEP magma ascended through dikes comparable in size to those that fed the lunar mare, it most likely erupted below its liquidus in the range of 1180 ​°C to 1160 ​°C, with effective viscosities in the range 103–107 ​Pas and traversing the lunar crust on timescales of minutes to hours.

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KREEP 模拟岩浆的流变学：应用于通过月球地壳的堤防上升的实验结果

摘要 在阿波罗返回的样本中，属于 KREEP 组的玄武岩被认为是通过岩脉传播从位于月球地壳下方的残余岩浆层作为凝固的月球岩浆的最后一部分喷发的~4.1-3.9 Ga海洋。到达月球表面的 KREEP 岩浆的侵位动力学通常知之甚少，部分原因是没有流变学数据可用于详细模拟 KREEP 上升条件，即使是在 KREEP 玄武岩发现约 50 年后。这项研究提供了 KREEP 岩浆的第一个流变学数据，作为温度和晶体含量的函数，从液相线温度 (~1205°C) 到~1177°C 时~16% 的晶体体积。熔岩的流变行为在液相线以下冷却几度时就变成非牛顿流变行为，并且可以用剪切稀化幂律方程很好地表示。我们将这些数据应用于浮力驱动的堤坝上升模型，表明如果 KREEP 岩浆上升通过大小与喂养月球母马的堤坝相当的堤坝，它很可能在 1180°C 至 1160°C 的液相线以下喷发°C，有效粘度在 103–107 Pas 范围内，并在几分钟到几小时的时间尺度上穿过月球地壳。