What drives the formation of basaltic melts beneath intraplate volcanoes not associated with extensive thermal anomalies or lithospheric extension? Detailed constraints on the melting conditions and source region are imperative to resolve this question. Here we model the geochemistry of alkali basalts and mantle nodules brought up by young (12–0.1 Ma) intraplate volcanoes distributed across the Carpathian‐Pannonian region and combine the results with geophysical observations. Rare earth element inversion and forward calculation of elemental concentrations show that the basalts require the mantle to have undergone less than 1% melting in the garnet‐spinel transition zone, at depths of about 63–72 km. The calculated melt distributions correspond to a mantle potential temperature of ∼1257°C, equivalent to a real temperature of 1290°C at 65 km beneath the Pannonian Basin. The composition, modal mineralogy, and clinopyroxene geochemistry of some of the entrained mantle nodules closely resemble the basalt source, though the latter equilibrated at greater depths. The gravity anomalies and topography of the Basin reveal no large‐scale features that can account for the post‐extensional volcanism. Instead, the lithospheric thickness and geotherm show that melting occurs because the base of the lithosphere, at ∼50‐km depth, is close to or at the solidus temperature over a large part of the Basin. Hence, only a small amount of upwelling is required to produce minor volumes (up to a few cubic kilometers) of melt. We conclude that the Pannonian volcanism originates from upwelling in the asthenosphere just below thinned lithosphere, which is likely to be driven by thermal buoyancy.

中文翻译：

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从火山岩和地震学估算喀尔巴阡—潘诺尼上地幔的温度和融化条件

是什么推动了板内火山下玄武质熔体的形成而与广泛的热异常或岩石圈扩展无关？对熔化条件和源区的详细限制对于解决这个问题势在必行。在这里，我们模拟了分布在喀尔巴阡—潘诺尼亚地区的年轻（12–0.1 Ma）板内火山带来的碱性玄武岩和地幔结核的地球化学，并将结果与​​地球物理观测结果相结合。稀土元素反演和元素浓度的正向计算表明，玄武岩要求地幔在石榴石-尖晶石过渡带中约63-72 km的深度融化不到1％。所计算的熔融分布对应的电势地幔温度〜1257°C，相当于Pannonian盆地下方65 km处的实际温度1290°C。一些夹带的地幔结核的组成，模态矿物学和斜辉石地球化学与玄武岩源极为相似，尽管后者在更深的深度达到了平衡。盆地的重力异常和地形没有发现可解释伸展后火山作用的大尺度特征。取而代之的是，岩石圈厚度和地热表明发生熔化，因为岩石圈的基础上，在〜50 km的深度接近或大部分位于盆地的固相线温度。因此，只需要少量的上升流就可以产生少量（最多几立方公里）的熔体。我们得出的结论是，潘诺尼火山活动起源于变薄的岩石圈以下的软流圈的上升，这很可能是由热浮力驱动的。