Collaborative Research: Allan HILLs Englacial Site (AHILLES) Selection

海洋古气候档案显示，大约100万年前，地球气候从4万年的冰川/间冰期周期过渡到10万年的周期。该奖项将支持一项研究，该研究旨在使用最先进的探地雷达绘制南极洲艾伦山蓝冰区100万年前冰的分布图。艾伦山被证明包含了过去40万年的连续记录，也是迄今发现的最古老的冰样(99万年)的收集地。这项研究产生的地图将被用来选择一个冰芯钻探地点，在那里可以恢复100多年前的连续气候记录。冰芯包含唯一一种直接捕获大气气体和气溶胶的记录，但还没有基于冰芯的气候记录持续延伸到过去80万年以上。一个100多万年前的记录将使人们能够更好地了解在一个有着10万年冰川/间冰期周期的世界中自然气候变化的主要机制和驱动力。该项目将与资深科学家以及一名研究生合作，支持两名早期职业科学家，并将向学校和公众进行外联。Allan Hills Blue Ice区域沿着一条既定的冰川流线保存了过去40万年的连续气候记录。在这条流线以东两公里处，地球上最古老的冰(约100万年前)仅在地表以下120米处被发现。据报道，在该地区收集的陨石年龄长达180万年，这表明可能存在更古老的冰。总而言之，这些数据有力地表明，艾伦山地区可能包含一个连续的、分辨率良好的环境记录，至少跨越了过去100万年。因此，这一地区已被美国冰芯工作组选为即将进行的新的中深度冰芯钻探的目标。这次钻探将回收比以前的干式钻探尝试更高质量的岩心。该项目将进行一项全面的探地雷达调查，目的是在整个区域追踪百万年前冰层的特征。生成的地图将用于选择钻探地点，从那里收集包含100万多年连续气候记录的冰芯。拟议的活动是收集地球上已知的最古老冰的必要先驱。冰芯提供了对过去气候的强有力的重建，将这一记录延长到目前可用的80万年之后，将为研究气候系统打开新的机会。收集的数据还将用于调查有利于保存旧冰的基岩和冰流参数，这可能使有针对性地调查南极洲其他蓝色冰区。

Marine paleoclimate archives show that approximately one million years ago Earth's climate transitioned from 40,000-year glacial /interglacial cycles to 100,000-year cycles. This award will support a study designed to map the distribution of one million year-old ice in the Allan Hills Blue Ice Area, Antarctica using state-of-the-art ground penetrating radar. The Allen Hills was demonstrated to contain a continuous record of the past 400,000 years and is also the collection location of the oldest ice samples (990,000 years) yet recovered. The maps resulting from this study will be used to select an ice-core drilling site at which a million-plus year-old continuous record of climate could be recovered. Ice cores contain the only kind of record to directly capture atmospheric gases and aerosols, but no ice-core-based climate record yet extends continuously beyond the past 800,000 years. A million-plus year-old record will allow better understanding of the major mechanisms and driving forces of natural climate variability in a world with 100,000-year glacial/interglacial cycles. The project will support two early career scientists in collaboration with senior scientists, as well as a graduate student, and will conduct outreach to schools and the public.The Allan Hills Blue Ice Area preserves a continuous climate record covering the last 400,000 years along an established glaciological flow line. Two kilometers to the east of this flow line, the oldest ice on Earth (~1 million years old) is found only 120 m below the surface. Meteorites collected in the area are reported to be as old as 1.8 million years, suggesting still older ice may be present. Combined, these data strongly suggest that the Allen Hills area could contain a continuous, well-resolved environmental record, spanning at least the last million years. As such, this area has been selected as an upcoming target for the new Intermediate Depth Ice Core Drill by the US Ice Core Working Group. This drill will recover a higher-quality core than previous dry drilling attempts. This project will conduct a comprehensive ground penetrating radar survey aimed at tracing the signature of the million-year-old ice layer throughout the region. The resulting map will be used to select a drill site from which an ice core containing the million-plus year-old continuous climate record will be collected. The proposed activities are a necessary precursor to the collection of the oldest known ice on Earth. Ice cores provide a robust reconstruction of past climate and extending this record beyond the 800,000 years currently available will open new opportunities to study the climate system. The data collected will also be used to investigate the bedrock and ice flow parameters favorable to the preservation of old ice, which may allow targeted investigation of other blue ice areas in Antarctica.