Collaborative Research: Development of paleo-proxy to test the sensitivity of the Southern Greenland Ice Sheet to future warming

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。在GIS行为的古重建中，一个重要的缺失部分是缺乏明确的冰盖示踪剂。利用陆源物源标记和格陵兰岛南部不同的基岩地层时代（太古宙与不同的元古代时代），提出了格陵兰冰盖（GIS）退缩和空中范围的示踪剂开发。具体来说，将对来自格陵兰岛南部地质地形的悬浮物沉积物进行采样。测定悬载沉积物的微量元素和Sr-Nd-Pb同位素组成，测定沉积物的磁性能。这些数据将与先前在格陵兰岛南部的一个岩心上进行的和新的测量结果进行比较，这些岩心来自一个经过充分研究的沉积物序列，跨越了过去430年和5个间冰期。对活塞岩心样品的同位素研究将重点放在淤泥粒度分数上，以尽量减少远行粘土粒度沉积物的影响。浮冰沉积物也将被避免。微量元素记录与以前和新获得的磁记录相结合，将通过确定冰盖退缩的时间和持续时间，提供南方地理信息系统对变暖气候的响应时间的估计。Sr-Nd-Pb同位素示踪剂将允许计算沉积物来源和何时冰从格陵兰岛南部部分地区消退，从而估计其对海平面上升的贡献。特别是，在核心地点相对年轻的元古代沉积物的消失使GIS南部边缘落后于其目前的位置。随后太古宙沉积物的减少和中期元古代沉积物的优势使GIS南部边缘位于格陵兰中部。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Stoner 0902751Oregon State UniversityA significant missing component in paleo-reconstructions of GIS behavior has been the lack of an unambiguous ice sheet tracer. The development of such a tracer for the Greenland Ice Sheet (GIS) retreat and aerial extent is proposed using terrigenous provenance markers and the different bedrock terrane ages of southern Greenland (Archean versus varying Proterozoic ages). Specifically, streams will be sampled for suspended load sediment from the geologic terranes of southern Greenland. Suspended load sediment will be measured for trace-element and Sr-Nd-Pb isotope composition, and magnetic properties of the sediment will be determined. These data will be compared with previously made and new measurements on a core off of southern Greenland from a well-studied sediment sequence spanning the last 430 kyrs and 5 interglacials. Isotope studies on piston core samples will focus on the silt size fraction in order to minimize the influence of far traveled clay size sediment. Ice rafted sediment will also be avoided. Trace element records combined with previous and newly obtained magnetic records will provide estimates of the response time of the southern GIS to a warming climate by identifying the timing and duration of ice sheet retreat. The Sr-Nd-Pb isotope tracers will allow calculations of sediment sources and when ice retreated off portions of southern Greenland, thus estimating its contribution to higher sea levels. In particular, the disappearance of relatively young Proterozoic sediment at the core site places the southern GIS margin behind its current location. A subsequent reduction in Archean sediment and dominance of intermediate age Proterozoic sediment places the southern GIS margin in central Greenland.