GLOW Tropical temperature history during Palaeogene global warming events

新生代代表了地球气候系统从温暖的温室世界转变为寒冷的冰窖世界的时期。在总体上已经变暖的古近纪期间发生了几次快速的全球变暖事件（例如，Zachos， Kroon等人，2004；Lourens等人，2005）。这一建议的核心是更好地理解气候系统在长期和短期时间尺度上的这种变化背后的过程。具体来说，我们的目标是记录西印度洋系统对这些全球气候变化的响应，例如西印度洋的生物地球化学状态、海面温度的变化和生物群的演变。这些古近纪的极端温暖期具有重要的社会意义；解决温度和气候反馈将为未来可能的气候模式和海洋的生物地球化学状态提供有价值的见解。在这里，我们建议将坦桑尼亚的陆上钻井样带（Nicholas et al., in press）扩展到海上，以完成从浅层环境到深海的这一样带。我们的目标是在坦桑尼亚近海进行现场调查，以获得地震线网格，这些网格随后可用于IODP钻井方案和/或IMAGES方案，以优化沿深度样带的多个钻孔位置和/或巨型活塞岩心的选择。地震剖面与随后的IODP钻探相结合，使我们有机会将现有的陆上证据片段整合在一起，并将其与新的海上数据相结合，为坦桑尼亚南部大陆边缘从二叠纪到近代的地质演化建立一个全面的构造、地层和沉积学框架。

The Cenozoic represents a period during which the Earth¿s climate system switched from a warm, greenhouse to a cold, icehouse world. Several rapid global warming events occurred during the in general already warm Paleogene (e.g., Zachos, Kroon et al., 2004; Lourens et al., 2005). Central in this proposal is better understanding of processes that underlie such switches of the climate system at long- and short timescales. Specifically, we aim to document the response of the West Indian Ocean system to these kind of global climate changes, e.g. the biogeochemical state of the western Indian Ocean, the variability of the sea surface temperatures and evolution of biota. These Paleogene intervals of extreme warmth are of significant societal interest; resolving temperature and climate feedbacks will provide valuable insights into possible future climate patterns and biogeochemical state of the ocean. Here, we propose to extend the onshore Tanzanian drilling transect (Nicholas et al., in press) to offshore to complete this transect from shallow environments to the deep sea. We aim to perform a site survey offshore Tanzania to obtain a grid of seismic lines which can subsequently be used in an IODP drilling proposal and/or IMAGES proposal to optimize choice of multiple borehole locations and/or giant piston cores along a depth transect. The seismic profiles, combined with drilling on a subsequent IODP leg, give us the opportunity to draw together existing but disparate fragments of onshore evidence and integrate them with new offshore data to build a comprehensive tectonic, stratigraphic and sedimentological framework for the geological evolution of the southern Tanzanian continental margin from the Permian to Recent.