Paleobathymetry of the Southern Ocean and its role in paleoclimate variations

南大洋拥有世界上最大和最活跃的海洋环流系统，在很大程度上影响着全球气候变化。了解过去的南大洋环流过程有助于解释目前对海洋参数变化的观测，并有助于改善对气候变化的预测。通过开发从共轭大陆架到深海平原的统一的南大洋数字地层学，该项目旨在生成一系列古水深时间网格，这些网格对于了解长时间尺度的古海洋环流和气候变化至关重要。选择合适的DSDP、ODP和IODP钻井地点以及现有地震测线的大型网络将作为地层约束的关键数据集。南大洋古等深线格网中纳入了最新的板块运动学模型、岩石圈沉降参数和动态地幔地形模型，将用于模拟古海洋学和古气候情景，特别强调南大洋门户的打开、地形沿着扩张脊的发展、断裂带和海洋高原以及沿着大陆架、斜坡和隆起的水团生成和洋流动态。该项目的最终目的是利用各种地球系统模型重建新生代气候，以评估海洋门户和盆地对古环流模式、全球碳循环和极地冰盖发展性质的影响。这些实验将包括灵敏度运行纳入新的古水深和古地形重建。这些实验的结果与其他模型模拟进行了比较，其中包括不同的强迫因素，如大气温室气体和山脉隆起，以确定古地理对长期地质时间尺度上全球气候演变的相对重要性。

The Southern Ocean hosts the worldwide largest and most dynamic ocean circulation system affecting global climate variations in a major extent. Understanding past Southern Ocean circulation processes help decipher present observations of changing oceanic parameters and help improve predictions of climate variations. By developing a unified Southern Ocean digital stratigraphy from the conjugate continental shelves to the abyssal plains, this project is aimed to generate series of paleobathymetric grids of times that are critical for understanding paleo-ocean circulation and climatic changes at long time-scales. A selection of suitable DSDP, ODP and IODP drill sites as well as the large network of existing seismic lines will serve as the key datasets for stratigraphic constraints. The Southern Ocean paleobathymetric grids, in which newest plate-kinematic models, lithospheric subsidence parameters and models of dynamic mantle topography are incorporated, will be used to simulate paleoceanographic and paleoclimate scenarios with particular emphasis on the opening of Southern Ocean gateways, the development of topographies along spreading ridges, fracture zones and oceanic plateaus as well as the water mass generation and ocean current dynamics along the continental shelves, slopes and rises. The ultimate aim of the project is to generate Cenozoic climate reconstructions using a variety of Earth system models designed to evaluate the effect of ocean gateways and basins on paleo-circulation patterns, the global carbon cycle and nature of polar ice sheet development. These experiments will include sensitivity runs incorporating the new paleobathymetric and paleotopographic reconstructions. The results from these experiments are compared with other model simulations, which include different forcing factors such as atmospheric greenhouse gasses and mountain uplift to determine the relative importance of paleo-geography on the evolution of global climates over long geological timescales.