Abstract The outer Ross Sea continental shelf has experienced large variations in ice sheet extent over the Pleistocene that are theorized to be largely driven by changes in the westward-flowing Antarctic Slope Current (ASC) at the continental shelf break. This current regulates southward incursions of warm modified Circumpolar Water, and it is thought to have triggered past marine ice sheet retreat. Additionally, expansions of grounded ice sheets on the continental shelf have fundamentally altered the Ross Sea water mass formation processes, influencing surface water salinity, sea ice cover, nutrient utilization, deep-water ventilation, and primary productivity. Here, we report the geochemical, physical properties, grain size, bulk δ15N, and diatom records during the late Pleistocene from two sediment cores from the Iselin Bank on the outermost continental shelf in the Ross Sea. These core sites were not overridden by grounded ice sheets during the late Pleistocene glacial-interglacial cycles, allowing for a continuous archive of glacimarine environments that were influenced by the ASC. Interglacial periods are typically characterized by high surface water productivity and nutrient utilization, with Chaetoceros resting spores indicating nutrient limitation under open ocean conditions, and glacial periods are typically characterized by low surface water productivity and nutrient utilization, with sea ice diatoms and planktonic foraminifers indicating light limitation under extensive sea ice/ice margin proximal conditions. A grain size analysis indicates coarse-skewed distributions and winnowing in the Iselin Bank region during cold periods. The winnowing may be related to enhanced ASC flow instead of density driven shelf water outflow.

中文翻译：

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罗斯海晚更新世古海洋学变化——古生产力、养分利用和深水形成的冰期-间冰期变化

摘要 罗斯海外大陆架在更新世期间经历了冰盖范围的巨大变化，理论上这主要是由大陆架断裂处向西流动的南极坡流 (ASC) 的变化驱动的。这股洋流调节了温暖的改良环极水向南侵入，它被认为引发了过去的海洋冰盖退缩。此外，大陆架上接地冰盖的扩张从根本上改变了罗斯海水团的形成过程，影响了地表水盐度、海冰覆盖、养分利用、深水通风和初级生产力。在这里，我们报告了地球化学、物理特性、晶粒尺寸、体积 δ15N、更新世晚期来自罗斯海最外大陆架上伊瑟林海岸的两个沉积岩芯的硅藻记录。在更新世晚期冰川-间冰期循环期间，这些核心地点没有被接地冰盖覆盖，从而可以对受 ASC 影响的冰川环境进行连续存档。间冰期的典型特征是地表水生产力和养分利用率高，毛角藻静止孢子表明在开阔的海洋条件下养分有限，冰川期的典型特征是地表水生产力和养分利用率低，海冰硅藻和浮游有孔虫表明光在广泛的海冰/冰缘近端条件下的限制。粒度分析表明，在寒冷时期，Iselin Bank 地区存在粗斜分布和风选。风选可能与增强的 ASC 流有关，而不是与密度驱动的陆架水流出有关。