FESD Type I: VOICE - Volcano, Ocean, Ice, and Carbon Experiments

地球上的两个主要现象是冰河期和火山爆发。这项研究解决了地球上这两个看似无关的方面如何相互影响的问题。两者之间的一个因果关系是冰和海洋对地球内部施加的压力。火山活动对这种压力变化很敏感。第二个因果关系是因为火山是自然排放到大气中的二氧化碳的最终来源，而二氧化碳对气候有显著的影响。在冰期循环期间，大量的水在大陆和海洋之间转移，消除了厚厚的冰盖，改变了海平面。融化的冰打开了火山，导致了数千年来更加活跃的大陆火山活动的脉动。冰川引起的海平面变化应该会影响海洋脊下地球内部融化的程度。随着海平面的上升和下降，形成海洋地壳的融化量应该会变化10%左右，从而导致海洋地壳的厚度和海底的深度发生变化。这可以解释海底起伏的地形，即所谓的深海山。洋脊火山活动的变化也可能导致热液活动的变化，从而影响深海生态系统和海洋的地球化学收支。冰川消融后的大火山脉冲可能会向大气中添加大量的二氧化碳，从而导致冰河时代结束时的快速变暖。最终，更好地了解火山二氧化碳排放对气候的影响可以为理解人类二氧化碳排放的重要性提供一个重要的背景。为了测试这些潜在的关系，我们将新的观察结果与定量建模相结合。高分辨率的海底地图将提供测深数据，以测试深海山丘是否随气候周期而变化。洋脊附近的新沉积物岩心将揭示热液活动是否也随着冰川循环而变化，以及变化的程度。对海底火山岩的取样和分析将显示地球内部的融化是如何随时间变化的。海上工作将在两艘游轮上进行，一艘在美国海洋研究船上，另一艘与德国调查人员合作。在陆地上，我们将与美国地质调查局的主要火山学家合作，调查喀斯喀特火山在最近冰川周期中的火山信号。新测量的年龄将限制火山对冰川反应的时间。地球化学分析将限制火山作用对冰川变化的反应，以及二氧化碳排放量的变化幅度。建模工作将精确地调查冰盖和海平面的变化是如何引起陆地和海底火山区域下的压力变化的，并生成地球内部融化的定量模型以及它如何对海平面变化作出反应。最终目标是建立一个综合模型，将火山活动、二氧化碳和气候联系起来，并测试它们在许多冰川循环的时间周期中如何相互作用。从本质上讲，我们正在探索地球内部和地球气候之间的耦合，也许会发现，甚至海底的结构也可能对气候变化做出反应，气候变化最终是由地球接收的太阳能量的变化引起的，冰川周期受到固体地球脉动的影响。

Two of the major phenomena on Earth are ice ages and volcanic eruptions. This research addresses the question how these two seemingly unrelated aspects of our planet may influence one another. One causal link between the two is the pressure exerted by ice and the oceans on Earth's interior. Volcanism is sensitive to such changes in pressure. A second causal link occurs because volcanoes are the ultimate source of natural CO2 delivered to the atmosphere, and CO2 has a marked influence on climate. During an ice age cycle, vast quantities of water are transferred between continents and oceans, eliminating thick ice sheets and changing sea level. Melting ice uncorks volcanoes, leading to a pulse of much more active continental volcanism for several thousand years. Glacially induced sea level change should influence how much Earth's interior melts beneath ocean ridges. As sea level rises and falls the amount of melt delivered to make the ocean crust should vary by about ten percent, leading to changes in the thickness of the ocean crust and the depth of the sea floor. This could be the explanation for the undulating topography of the sea floor known as abyssal hills. The changes in volcanism at ocean ridges could also lead to changes in hydrothermal activity that would influence deep sea ecosystems and affect geochemical budgets of the oceans. The large volcanic pulse following de-glaciation could add large amounts of CO2 to the atmosphere, contributing to the rapid warming that occurs at the end of ice ages. Ultimately, a better understanding of the influence of volcanic CO2 emissions on climate could provide an important context for understanding the significance of human CO2 emissions. To test these potential relationships, we combine novel new observations with quantitative modeling. High resolution maps of the sea floor will provide the bathymetric data to test whether abyssal hills vary with climate cycles. New sediment cores near ocean ridges will reveal whether hydrothermal activity also varies with glacial cycles, and how much it varies. Sampling and analysis of the volcanic rocks of the sea floor will show how melting of Earth's interior varies over time. The sea-going work will take place on two cruises, one on a U.S. oceanographic vessel and the other in collaboration with German investigators. On land, we will collaborate with leading volcanologists from the U.S. Geological Survey to investigate the volcanic signal of Cascades volcanoes over recent glacial cycles. Newly measured ages will constrain the timing of the volcanic response to glaciation. Geochemical analyses will constraint how volcanism responds to glacial changes, and how much CO2 emissions may vary. Modeling work will investigate exactly how changes in ice sheets and sea level cause pressure changes beneath volcanic regions on land and undersea, and generate quantitative models of melting of Earth's interior and how it responds to sea level change. The final aim is an integrated model that links volcanism, CO2 and climate and tests how they may interact with one another over time periods of many glacial cycles. In essence, we are exploring the coupling between Earth's interior and Earth's climate, perhaps discovering that even the fabric of the ocean floor may be responding to climate change ultimately caused by variations in the amount of solar energy our planet receives, and that glacial cycles are influenced by the pulse of the solid Earth.