A major topic of debate in earth science and climate science surrounds the timing of closure of the Central American Seaway. While it is clear that the gateway was closed by ca. 2.8 Ma, recent studies based on geological and marine molecular evidence have suggested an earlier closing time of early to mid-Miocene. In this study, we examined the influences of subduction and slab window formation on the time-varying paleoenvironments of the Isthmus of Panama region. We developed detailed reconstructions of the seafloor spreading history in the Panama Basin and incorporated previously published arc block rotations into a revised global plate model. Our reconstructions indicate that the Central American Seaway region has undergone multiple phases of slab window formation and migration, slab detachment, and flat slab subduction since the Oligocene, while kinematically mapped slab windows agree well with slab gaps imaged in seismic tomography. In particular, we found that from the early Miocene, when there is clear evidence for Isthmus of Panama emergence, the region was underlain by a slab window. During the late Miocene, when there is evidence for intermittent arc deepening, and decreased transcontinental migration, we found an increase in subducted slab volumes beneath the Panama arc. Numerical and analogue models and field observations argue that slab windows can induce >1 km of vertical uplift on the overriding plate. We therefore propose that this previously unexplored geodynamic mechanism can explain the variations in Isthmus of Panama emergence, and intermittent shallow-water connections, reconciling alternative lines of evidence for Central American Seaway closure.

中文翻译：

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巴拿马地峡的运动学和地球动力学演变：对中美洲海上航道封闭的影响

地球科学和气候科学领域的一个主要辩论主题是中美洲海上航道的关闭时间。很明显，网关已被ca关闭。2.8 Ma，基于地质和海洋分子证据的最新研究表明，中新世早至中晚期为封闭期。在这项研究中，我们研究了俯冲和平板窗口形成对巴拿马地区地峡随时间变化的古环境的影响。我们开发了巴拿马盆地海底扩散历史的详细重建方法，并将先前发布的弧块旋转纳入了修订的全球板块模型中。我们的重建结果表明，自渐新世以来，中美洲海道地区经历了平板窗形成和迁移，平板脱离和平板平板俯冲的多个阶段，运动学映射的平板窗口与地震层析成像中成像的平板间隙非常吻合。特别是，我们发现，从中新世早期开始，当有明确的证据显示巴拿马地峡出现时，该地区就被厚厚的板状窗口所掩盖。在中新世晚期，有证据表明弧间断不断加深，而跨大陆迁移减少，我们发现巴拿马弧下方俯冲板块体积增加。数值和模拟模型以及现场观测结果表明，平板窗可以在上覆板上引起大于1 km的垂直隆起。因此，我们建议，这种以前未曾探索过的地球动力学机制可以解释巴拿马地峡出现的变化以及间歇性浅水连接，从而调和了中美洲海上航道封闭的替代证据。