Deglacial Transport through the Florida Straits: Constraints on Atlantic Ocean Circulation during the Younger Dryas, Heinrich Event 1 and the Last Glacial Maximum

在这个项目中，我们将研究大西洋环流在地球从上一个冰河时代出现时发生的气候突变期间是如何变化的。我们的数据将有助于检验这样的假设，即年轻的仙女座冷期是由大西洋经向翻转环流强度的减弱引起的，并且在海因里希事件期间大量淡水排放到北大西洋完全关闭了这种翻转。我们将利用氧同位素和镁钙比值以及对底栖生物和深水浮游有孔虫的测量来重建佛罗里达海峡水域的密度结构。这些信息将结合在一起，使用一种新的地转模拟方法，创建10,000至20,000年前佛罗里达海峡的千年尺度运输史，包括年轻的仙女木/博林Allerod气候振荡，Heinrich Event 1和最后一次冰川最大值。经向翻转环流的上端沿西边界向北大西洋移动时穿过佛罗里达海峡，翻转强度的任何大幅减弱都将反映在通过海峡的流量的减少上。在我们试图了解未来几个世纪气候的轨迹时，了解大西洋经向翻转环流过去的稳定性及其与气候突然变化的关系是社会非常感兴趣的。本科生和研究生将在合作这一项目的过程中接受培训。PI将通过与媒体和当地教育组织的接触，将这项研究传达给佐治亚理工学院的新一代学生和更广泛的社区。

In this project, we will investigate how Atlantic Ocean circulation changed during the abrupt climate changes that occurred as the earth emerged from the last Ice Age. Our data will help to test the hypotheses that the Younger Dryas cold period was caused by a decrease in the strength of the Atlantic meridional overturning circulation and that the large discharges of freshwater into the North Atlantic during Heinrich Events shut down this overturning altogether. We will reconstruct the density structure of waters in the Florida Straits using oxygen isotope and Mg/Ca and measurements on benthic and deep dwelling planktonic foraminifera. This information will be combined to create a millennial scale transport history for the Florida Straits between 10,000 and 20,000 years ago, including the Younger Dryas/Bolling Allerod climate oscillation, Heinrich Event 1 and the last glacial maximum, using a novel geostrophic modeling method. The upper limb of the meridional overturning circulation passes through the Florida Straits as it travels along the western boundary towards the North Atlantic and any substantial reductions in the strength of the overturning will be reflected in a reduction of the flow through the straits. Understanding the past stability of the Atlantic meridional overturning circulation and its relationship to abrupt climate change is of great interest to society as we seek to understand the trajectory of climate over the next centuries. Undergraduate and graduate students will be trained as they collaborate on this project. The PI will communicate this research to a new generation of students at Georgia Tech and to the broader community through contacts with the media and local educational organizations.