Detangling Flow Regimes and Paleoclimate in the Deepest Section of the EDML Ice Core using U-series Ages.

Aciego/1043367该奖项支持开发一种确定深冰芯样品绝对年龄的新方法。该项目将：（1）证明铀系定年方法在高积累率冰芯上的有效性;（2）解决EPICA德龙宁-莫德地（EDML）冰芯在300 m以下年龄测定中的不确定性。冰芯的上部（在2415.7米处可达150，000年）将为验证U系列方法确定的年龄提供很好的约束。经过验证，并可能调整实验室化学，该方法将被应用于一套冰样品的年龄未知的下部EDML冰芯。在冰芯下方300米的范围内，气候记录受到冰的倾斜和折叠的干扰，而且由于冰如何流动的不确定性，不可能确定是否可以获得准确的年龄来获得气候变化的记录，或者冰的混合是否太不连贯。作为方法的一部分，PI将使用为超小样品开发的气体吸附技术测量冰中所含灰尘的表面积;这些测量将在BET纳米尺度上进行，该尺度将从该项目的资金中购买。智力优势：拟议中的研究将有助于我们理解地球物理过程，折叠和倾斜冰。 这将使新的古气候记录恢复从冰芯已经物理变形和干扰，以前不允许准确的日期。 更广泛的影响：这笔资金将为一名博士研究生提供支持，并有助于他们成为地球化学和古气候研究的研究人员。PI将教授地球表面过程（包括冰川学）和高级同位素地球化学课程。 与本研究相关的工作将作为教学工具纳入课堂，提供动手，相关的学习经验。此外，作为这项研究的一部分，作为美国PI和欧洲冰芯社区合作的一部分，将从德国不来梅港的AWI档案馆提供样本。

Aciego/1043367This award supports the development of a new method for determining the absolute age of samples from deep ice cores. The project will: (1) prove the efficacy of the Uranium-series dating method on a high accumulation rate ice core, and (2) address the uncertainties in the age dating of the EPICA Dronning-Maud Land (EDML) ice core in the lower 300 m. The well-dated upper section of the ice core (down to 150,000 years at 2415.7 m) will provide excellent constraints to validate the ages determined by the U-series method. After verification, and possible adjustments to the laboratory chemistry, the method will be applied to a suite of ice samples of unknown age in the lower part of the EDML ice core. Within the lower 300 m of this ice core, the climate records are disturbed by tilting and folding of the ice, and, due to the uncertainties in how the ice has flowed, it is impossible to determine if accurate age dates can be obtained to access the record of climate change, or if mixing of the ice is too incoherent. As part of the methodology, the PI will measure surface area of dust included in the ice using a gas adsorption technique developed for ultra-small samples; these measurements will be made on a BET nano-scale which is to be purchased from the funding of this project. Intellectual Merit: The proposed research will contribute to our understanding of geophysical processes that fold and tilt ice. This will allow new paleoclimate records to be recovered from ice cores that have been physically deformed and disturbed and previously did not permit accurate dating. Broader Impacts: This funding will provide support for one PhD graduate student and contribute to their training as a researcher in geochemistry and paleoclimate studies. The PI will teach classes in earth surface processes (including glaciology) and in advanced isotope geochemistry. Work related to this research will be integrated as a teaching tool into the classroom to provide a hands-on, relevant learning experience. Furthermore, samples examined as part of this research will be made available from the AWI archive in Bremerhaven, Germany as part of the collaboration between the PI in the United States and the European ice core community.