Glacial History of Ridge AB, West Antarctica

0087144 conway该奖项支持使用成熟的地球物理方法研究南极洲西部Ridge AB的冰川历史。我们研究的动机是需要提高对南极西部排水系统的结构和活动如何变化的理解，以及这如何影响冰盖的稳定性。选择AB脊有以下几个原因：1)以前对西南极洲流间脊的研究已经揭示了许多关于周围冰流历史的信息。在冰盖的南部有一个“信息洞”；我们乐观地认为，我们对Ridge AB的研究将揭示冰流a和B的结构和活动的最新变化的新信息；2) Reedy冰川的地质证据表明，在末次盛冰期，AB岭附近的冰厚约700 m。这有助于限制发生在全新世的冰盖变薄的幅度，并开启了将南极西部冰盖的历史与横贯南极山脉的地质记录联系起来的可能性。我们的方法是首先绘制内部分层、埋藏裂缝、地表速度和积累速率的空间变化。主要的调查工具有：高频和低频雷达系统、GPS测量方法和短（20米）铁芯。诊断测量结果将用冰流模型进行检验，以推断山脊AB和周围冰流的冰川历史。这段历史将在其他冰间流山脊出现的历史的背景下进行解释，以及来自里德和其他跨南极山脉出口冰川的地质证据。我们的总体目标是提高对WAIS排水系统演变的理解。

0087144ConwayThis award supports the study the glacial history of Ridge AB in West Antarctica using well-established geophysical methods. Our study is motivated by the need to improve under-standing of how the configuration and activity of the West Antarctic drainage system is changing, and how this affects the stability of the ice sheet. Ridge AB has been chosen for several reasons: 1) previous studies of inter-stream ridges in West Antarctica have revealed much information about the history of the surrounding ice streams. There is an "information-hole" in the southern sector of the ice sheet; we are optimistic that our study of Ridge AB will reveal new information about recent changes in the configuration and activity of Ice Streams Aand B; 2) geologic evidence from Reedy Glacier indicates that ice in the vicinity of Ridge AB was ~700 m thicker during the last glacial maximum. This helps constrain the magnitude ofthinning that has occurred through the Holocene, and opens the possibility of linking thehistory of the West Antarctic Ice Sheet to the geologic record in the Trans-Antarctic Mountains. Our approach is to first map spatial variations of internal layering, buried crevasses, surface velocity, and accumulation rate. The main investigative tools are: high and low-frequency radar systems, GPS surveying methods, and short (20 m) firn cores. The diagnostic measurements will then be examined with ice flow models to infer the glacial history of Ridge AB and the surrounding ice streams. The history will be interpreted in context of the histories that are emerging from the other inter-ice stream ridges, as well as the geologic evidence from Reedy and other outlet glaciers in the Trans-Antarctic Mountains. Our overall goal is to improve understanding of the evolution of the WAIS drainage system.