Abstract Scotia Sea and the Drake Passage is key towards understanding the development of modern oceanic circulation patterns and their implications for ice sheet growth and decay. The sedimentary record of the southern Scotia Sea basins documents the regional tectonic, oceanographic and climatic evolution since the Eocene. However, a lack of accurate age estimations has prevented the calibration of the reconstructed history. The upper sedimentary record of the Scotia Sea was scientifically drilled for the first time in 2019 during International Ocean Discovery Program (IODP) Expedition 382, recovering sediments down to ∼643 and 676 m below sea floor in the Dove and Pirie basins respectively. Here, we report newly acquired high resolution physical properties data and the first accurate age constraints for the seismic sequences of the upper sedimentary record of the Scotia Sea to the late Miocene. The drilled record contains four basin-wide reflectors – Reflector-c, -b, -a and -a' previously estimated to be ∼12.6 Ma, ∼6.4 Ma, ∼3.8 Ma and ∼2.6 Ma, respectively. By extrapolating our new Scotia Sea age model to previous morpho-structural and seismic-stratigraphic analyses of the wider region we found, however, that the four discontinuities drilled are much younger than previously thought. Reflector-c actually formed before 8.4 Ma, Reflector-b at ∼4.5/3.7 Ma, Reflector-a at ∼1.7 Ma, and Reflector-a' at ∼0.4 Ma. Our updated age model of these discontinuities has major implications for their correlation with regional tectonic, oceanographic and cryospheric events. According to our results, the outflow of Antarctic Bottom Water to northern latitudes controlled the Antarctic Circumpolar Current flow from late Miocene. Subsequent variability of the Antarctic ice sheets has influenced the oceanic circulation pattern linked to major global climatic changes during early Pliocene, Mid-Pleistocene and the Marine Isotope Stage 11.

中文翻译：

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中新世将呈现斯科舍海和南极冰盖动力学的海洋变化：从 IODP 远征 382 之后修正的地震地层学的见解

摘要 斯科舍海和德雷克海峡是了解现代海洋环流模式的发展及其对冰盖生长和衰退的影响的关键。南斯科舍海盆地的沉积记录记录了自始新世以来的区域构造、海洋和气候演变。然而，缺乏准确的年龄估计阻碍了重建历史的校准。2019 年，在国际海洋发现计划 (IODP) 远征 382 期间，首次科学钻探了斯科舍海的上层沉积记录，分别在 Dove 和 Pirie 盆地恢复了海底以下约 643 米和 676 米的沉积物。这里，我们报告了新获得的高分辨率物理特性数据和第一个准确的年代限制，用于斯科舍海上部沉积记录到晚中新世的地震序列。钻探记录包含四个盆地范围的反射器——反射器-c、-b、-a 和 -a' 先前估计分别为~12.6 Ma、~6.4 Ma、~3.8 Ma 和~2.6 Ma。然而，通过将我们的新斯科舍海时代模型外推到之前对更广泛区域的形态结构和地震地层分析，我们发现钻探的四个不连续点比以前认为的要年轻得多。Reflector-c 实际上在 8.4 Ma 之前形成，Reflector-b 在 ∼4.5/3.7 Ma，Reflector-a 在 ∼1.7 Ma，Reflector-a' 在 ∼0.4 Ma。我们更新的这些不连续性的年龄模型对它们与区域构造的相关性具有重要意义，海洋和冰冻圈事件。根据我们的研究结果，南极底水向北纬的流出控制了中新世晚期的南极绕极流。南极冰盖的后续变化影响了与上新世早期、中更新世和海洋同位素第 11 阶段主要全球气候变化相关的海洋环流模式。