Abstract The southernmost South America has been affected by the subduction of an oceanic seismic ridge, which began to subduct below southern Patagonia at ∼14 Ma. This scenario led to the formation of a slab window, which is still active and where hot buoyant asthenospheric mantle produced thermal anomalies and modifications in the lithospheric thicknesses. Meanwhile, from the Patagonian Andes to the Atlantic coast, an outstanding regional surface uplift took place, conducting to a moderated-elevation plateau formation. In this work we analyzed the causes of this long-wavelength surface elevation change using residual topography and uplift rate calculations, considering paleo-lithospheric states. We achieved this considering that the study area underwent a lithospheric thickness changes through time, before and after the slab window formation. This allowed us to estimate the isostatic and dynamic adjustment over time and their influences on the surface elevation changes. These rates were compared with geological and stratigraphic observations derived from a key elevation marker bed: The modern altitudes of Oligo-Miocene marine strata top, originally deposited close or below sea level, and placed at Present at hundreds of meters above sea level. Our residual topography calculations, that result from comparing isostatic and observed topography, indicates the dynamic topography contribution in the study region was very minor (if so) to null. The isostatic uplift, in turn, shows a remarkable fitting with the reconstruction of marine marker bed, suggesting a causative relationship. We can assert that Patagonian lithospheric thinning, particularly of the lithospheric mantle, by slab window formation, would have been enough to reproduce the modern elevations and surface uplift across the plateau from the Miocene to Present day. Our work opens a question on the model that connect slab windows, asthenospheric upwelling flows with surface uplifting. However, as shown by recent works, lithospheric changes might trigger small convection cells, which might produce local and small dynamic topography.

中文翻译：

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巴塔哥尼亚南部（45˚-55˚S）板窗形成过程中岩石圈减薄和动态隆升效应

摘要 南美洲最南端受到大洋地震脊俯冲的影响，该地震脊在 14 Ma 时开始在巴塔哥尼亚南部下方俯冲。这种情况导致了板状窗口的形成，该窗口仍然活跃，并且热的浮力软流圈地幔产生了岩石圈厚度的热异常和变化。同时，从巴塔哥尼亚安第斯山脉到大西洋沿岸，区域地表隆升显着，形成中高程高原地层。在这项工作中，我们考虑到古岩石圈状态，使用残余地形和抬升率计算分析了这种长波长表面高程变化的原因。我们实现了这一点，因为研究区域在板窗形成之前和之后经历了岩石圈厚度随时间的变化。这使我们能够估计随时间的等静压和动态调整及其对地表高程变化的影响。将这些速率与源自关键海拔标记床的地质和地层观测进行了比较：渐新世海相地层顶部的现代海拔，最初沉积在海平面附近或以下，现在位于海平面以上数百米处。我们的残余地形计算是通过比较等静压和观察到的地形得出的，表明研究区域中的动态地形贡献非常小（如果是的话）甚至为零。反过来，等静压抬升显示出与海洋标记床重建的显着拟合，表明存在因果关系。我们可以断言，巴塔哥尼亚岩石圈变薄，特别是岩石圈地幔的变薄，通过平板窗的形成，足以再现从中新世到现在的整个高原的现代海拔和地表隆起。我们的工作提出了一个关于连接板窗、软流圈上升流与地表抬升的模型的问题。然而，最近的研究表明，岩石圈的变化可能会触发小的对流单元，这可能会产生局部和小的动态地形。