Exploring plate tectonic force balances and plate boundary forces in the South Atlantic from plate motion histories and coupled global and regional geodynamic models

南大西洋由于其被动的边缘环境，保存了过去板块运动的重要档案。尤其重要的是在大西洋中部海脊和Scotia和Sandwich弧后系统的扩张历史中记录的快速板块运动变化。它们的短暂持续使这些变化成为对板块运动的力平衡的敏感探测，特别是对于板块边界力，因为与地幔有关的过程在更长的时间尺度上演化。我们将使用耦合的地幔环流和新构造模型来研究地幔/岩石圈的力平衡。我们将特别注意远场效应，必须用全球模型来研究，以避免人为边界条件的影响。远场效应预计是相关的，因为初步模拟结果表明，南大西洋的扩散变化受到邻近大陆的近地表过程的影响。我们将汇编南大西洋扩张史的高分辨率(空间和时间)汇编，并利用它们详细的运动学约束来检验这样的假设，即邻近大陆的地形变化，如安第斯山脉的上升或南非的地形高位，是南大西洋构造演化的重要因素。将结合区域和全球地幔流动模型研究Scotia弧后盆地的演化。这项提议的资金将支持斯图尔特·克拉克的博士后培训，他通过与迪特马尔·穆勒的博士工作，带来了区域地幔流动建模和板块重建的独特背景，从而可以为更广泛的样本工作提供先进的板块重建和地球动力学模型。

The South Atlantic preserves a crucial archive of past plate motion due to its passive margin environment. Particularly important are rapid plate motion changes recorded in the spreading history of the mid-Atlantic ridge, and the Scotia and Sandwich back-arc system. Their short duration makes these changes sensitive probes into the force balance of plate motion, especially for plate boundary forces, as mantle related processes evolve on longer time-scales. We will investigate the mantle/lithosphere force balance using coupled mantle circulation and neo-tectonic models. We will pay particular attention to far-field effects which must be studied with global models to avoid influence from artificial boundary conditions. Far-field effects are expected to be relevant as indicated by preliminary modelling results suggesting that South Atlantic spreading variations are affected by near surface processes in the adjacent continents. We will assemble high-resolution (spatial and temporal) compilations of the South Atlantic spreading history, and exploit their detailed kinematic constraints to test the hypothesis that topography variations in the adjacent continents, such as the rise of the Andes or the topographic high stand of South Africa, are important factors in the tectonic evolution of the South Atlantic. Evolution of the Scotia back-arc basin will be studied with a combination of regional and global mantle flow models. Funds from this proposal will support the post-doctoral training of Stuart Clark, who brings a unique background of regional mantle flow modelling and plate reconstructions through his PhD work with Dietmar Müller, so that advanced plate reconstruction and geodynamic models can be made available to the broader SAMPLE effort.