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

由于其被动的边缘环境，南大西洋保存了过去板块运动的重要档案。特别重要的是，在大西洋中脊、斯科舍和桑威奇弧后系统的扩张历史中记录了板块的快速运动变化。这些变化持续时间短，是探讨板块运动力平衡，特别是板块边界力的灵敏探针，因为地幔相关过程在较长的时间尺度上演化。我们将使用耦合地幔环流和新构造模型研究地幔/岩石圈力平衡。我们将特别注意远场效应，这必须用全球模型来研究，以避免人工边界条件的影响。预计远场效应是相关的，初步模拟结果表明，南大西洋扩张变化受到邻近大陆近地表过程的影响。我们将组装高分辨率（空间和时间）的南大西洋扩张历史的汇编，并利用其详细的运动学约束来测试的假设，即在邻近大陆的地形变化，如安第斯山脉的崛起或南非的地形高位，是在南大西洋的构造演化的重要因素。斯科舍弧后盆地的演化将结合区域和全球地幔流模型进行研究。来自该提案的资金将支持Stuart Clark的博士后培训，他通过与Dietmar Müller的博士工作带来了区域地幔流建模和板块重建的独特背景，因此可以为更广泛的SAMPLE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.