LGM and Deglacial Radiocarbon from U-series Dated Drake Passage Deep-sea Corals

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。该提案寻求资金，以继续对在德雷克航道进行研究巡航期间收集的深海珊瑚进行后续分析工作。该项目的目标是进行古气候研究，以期限制冰川和冰川消融期间南大洋放射性碳含量的深度、结构和时间演变。放射性碳是过去气候的多功能示踪剂；它的放射性衰变提供了一个内部时钟，用来评估过程的速度，它可以用来追踪碳在地球系统中的移动。它通过气-海气体交换进入海洋，因此，限制这种交换的过程将减少表层和深海的放射性碳含量。南大洋是深海和大气水库之间交换热量和碳的关键位置，在那里形成的深水充满了大量的全球深洋和中洋。由于强流倾向于冲刷沉积物，碳酸盐保存有限，放射性碳化物储集层年龄限制较差，许多传统的古海洋学技术变得不切实际。建议缓解这些困难，分析深海珊瑚骨骼的化学成分。它们的文石骨架可以使用U系列衰变来精确测定年龄，当与放射性碳分析相结合时，将允许计算过去水柱的C14/C12比率。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The proposal seeks funds to continue a follow-up analytical work of deep-sea corals collected in the Drake Passage during a research cruise. The project's goal is paleo-climate research looking to constrain the depth structure and time evolution of the radiocarbon content of the Southern Ocean during the glacial and deglaciation. Radiocarbon is a versatile tracer of past climate; its radioactive decay provides an internal clock with which to assess the rates of processes, and it can be used to trace the movement of carbon through the Earth's system. It enters the ocean through air-sea gas exchange, so processes that limits this will, therefore, reduce the radiocarbon content of both surface and deep waters. The Southern Ocean is a critical location for exchange of heat and carbon between the deep-ocean and atmospheric reservoirs, and the deep waters formed there fill large volumes of the global deep and intermediate oceans. As strong currents tend to scour away sediments, carbonate preservation is limited, and radiocarbon reservoir ages are poorly constrained, many traditional paleoceanographic techniques become impractical. It is proposed to alleviate these difficulties analyzing the chemical composition of deep-sea coral skeletons. Their aragonitic skeletons can be precisely dated using U-series decay, and when coupled with radiocarbon analyses will allow to calculate the C14/C12 ratio of the past water column.