Southern Alaska margin: interactions of tectonics, climate, and sedimentation (Integrated Ocean Drilling Program Expedition 341)

在大气二氧化碳浓度较高的情况下对未来气候变化的预测取决于我们对不同气候成分之间的关系和反馈的理解，这些气候成分可以是过程(海洋环流、冰盖行为)，也可以是区域(例如，低纬度与高纬度)。过去，现代气候系统中的许多关键变量都与重大气候转变有关，但它们是否会驱动、放大或响应气候事件，仍然是一个激烈辩论的话题。这次研究探险的重点是在靠近南阿拉斯加的样带上钻探一系列海洋沉积物岩心，以调查造山、冰盖增长和气候变化之间的联系。最近的研究表明，山脉的隆起可以通过影响降水的路径和强度来影响当地和区域的气候。它还可能导致冰盖的生长，并增加对陆地表面的侵蚀。从山区向海洋输送更多的沉积物和淡水可能会影响生物生产力和山脉附近地区的海洋环流模式。相反，也有人提出，区域尺度(如北太平洋)的冷却和海洋环流变化对于允许或鼓励冰盖的增长可能很重要，而区域变暖可能对推动冰盖的消退很重要。这一组复杂的相互作用很难评估，因为很少有机会恢复包含气候信号和侵蚀和冰盖生长/衰退证据的长序列沉积物。在这次探险中，我们将发现一系列岩芯，这些岩芯距离海岸越来越近，跨越数百万年，但也保存了快速气候事件和岸上环境条件反应的证据。这一结果将对气候变化、构造学、生物地球化学循环、冰川学和流域动力学等广泛的学术兴趣产生重要影响。

Projections of future climate change under higher atmospheric carbon dioxide concentrations rely upon our understanding of the relationships and feedbacks that operate between different climate components, either as processes (ocean circulation, ice-sheet behaviour) or regions (e.g. low versus high latitudes). A number of key variables within the modern climate system have been linked to major climate transitions in the past, but whether they drove, amplified, or responded to climate events remains a topic of intense debate.The focus of this research expedition is to drill a series of marine sediment cores in a transect close to South Alaska, in order to investigate the links between mountain building, ice sheet growth, and climate change. Recent research has shown that the uplift of mountains can affect local and regional climate by affecting the pathways and intensities of precipitation. It can also lead to ice sheet growth, and to increased erosion of the land surface. The increase delivery of sediments and freshwater from the mountains to the ocean can affect biological productivity and the patterns of ocean circulation in areas proximal to the mountains. In contrast, it has also been proposed that cooling and changes in ocean circulation at a regional scale (e.g. across the North Pacific Ocean) could be important for allowing or encouraging the growth of ice sheets, and regional warming might be important for driving ice-sheet retreat.This complex set of interactions has been difficult to assess because there has rarely been an opportunity to recover long sequences of sediments which contain both climate signals and evidence for erosion and ice sheet growth/decay. In this expedition we will recover a series of cores which are progressively closer to shore, which span millions of years but which also preserve evidence for rapid climate events and the response of the environmental conditions onshore. The results will be important for a wide range of academic interests, spanning climate change, tectonics, biogeochemical cycling, glaciology and catchment dynamics.