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

地球上的两个主要现象是冰河时代和火山喷发。这项研究解决了地球上这两个看似不相关的方面可能会如何相互影响的问题。两者之间的一个因果联系是冰和海洋对地球内部施加的压力。火山作用对这种压力变化很敏感。出现第二个因果联系是因为火山是排放到大气中的天然二氧化碳的最终来源，而二氧化碳对气候有显著影响。在冰河周期中，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的软木塞，导致了数千年来更加活跃的大陆火山活动。冰川引起的海平面变化应该会影响地球内部在海脊下融化的程度。随着海平面的上升和下降，形成洋壳的熔融量应该会有大约10%的变化，这会导致洋壳的厚度和海底深度的变化。这可能是海底起伏的地形被称为深海丘陵的原因。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。冰川消融后的巨大火山脉冲可能会向大气中添加大量二氧化碳，导致冰河时代结束时发生的快速变暖。归根结底，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重要背景。为了测试这些潜在的关系，我们将新的新观察与定量建模相结合。高分辨率的海底地图将提供水深数据，以测试深海丘陵是否会随着气候周期的变化而变化。海脊附近新的沉积物岩心将揭示热液活动是否也随冰川周期而变化，以及变化幅度。对海底火山岩的采样和分析将显示地球内部的融化如何随着时间的推移而变化。出海工作将在两次巡航中进行，一次是在一艘美国海洋船上，另一次是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，调查喀斯喀兹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可能会有多少变化。建模工作将准确地调查冰盖和海平面的变化如何导致陆地和海底火山区下方的压力变化，并生成地球内部融化的定量模型以及它对海平面变化的反应。最终目标是一个将火山作用、二氧化碳和气候联系起来的综合模型，并测试它们在许多冰川周期的一段时间内如何相互作用。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，即使是海底的结构也可能对气候变化做出反应，最终导致气候变化的原因是我们的星球接收到的太阳能总量的变化，以及冰川周期受到固体地球脉冲的影响。

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.