Collaborative Research: New Constraints on Post-Glacial Rebound and Holocene Environmental History along the Northern Antarctic Peninsula from Raised Beaches

非技术性描述南极洲的冰川冰损失有可能导致全球海平面显著上升。 全球定位系统接收器测量到的南极半岛陆地上升的速度加快，这是冰川融化加速的一个证据。 然而，全球定位系统（GPS）对隆升的观测仅限于最近二十年。 这项研究的一个目标是确定这些新观察到的隆升速率如何与南极半岛在较长时间间隔内的平均隆升速率进行比较。研究人员将利用南极洲半岛低洼沿海丘陵上的古海滩的年龄和海拔来重建过去的海平面，以确定过去5,000年来的上升速度。 研究人员还将使用探地雷达分析海滩的结构和海滩沉积物的特征，以了解海平面上升和过去的气候变化是如何记录在海滩沉积物中的。 这些新记录的好处将有三个方面：（1）它们将有助于确定南极冰盖的自然变化和相对海平面;（2）它们将提供关于隆起和地球内部结构的新见解;以及3）它们将帮助研究人员改进用于确定地质沉积物年龄的方法。 研究结果将在K-12学校的外展活动中与圣巴巴拉自然历史博物馆的游客分享。 三名研究生将通过该项目得到支持。 古海平面数据对于重建过去冰盖的大小和范围，记录冰川退缩后上升的幅度，以及校正基于重力的冰量损失测量结果以反映冰后反弹的影响至关重要。然而，只有14个地点有南极洲的相对海平面数据，而最近对北美冰盖复合体的研究中使用了500多个地点。 本项目的目的是利用光激发光法测定东南极半岛沿线沿着一系列新发现的隆起海滩的年代，以及南设得兰群岛一系列已知但仅初步确定年代的隆起海滩的年代。在隆起的海滩收集的数据包括年龄和海拔、地面穿透雷达剖面、鹅卵石的圆度和冰筏碎片的岩性。本研究将检验三个假设：（1）相对于全新世晚期，南极半岛的现代抬升速率有所增加;（2）南极半岛北方的海平面历史与南设得兰群岛的海平面历史明显不同;（3）卵石圆度与冰源--上升的海滩上的漂流碎片随时间系统地变化，反映了南极半岛北方的气候历史。

Nontechnical DescriptionGlacier ice loss from Antarctica has the potential to lead to a significant rise in global sea level. One line of evidence for accelerated glacier ice loss has been an increase in the rate at which the land has been rising across the Antarctic Peninsula as measured by GPS receivers. However, GPS observations of uplift are limited to the last two decades. One goal of this study is to determine how these newly observed rates of uplift compare to average rates of uplift across the Antarctic Peninsula over a longer time interval. Researchers will reconstruct past sea levels using the age and elevation of ancient beaches now stranded above sea level on the low-lying coastal hills of the Antarctica Peninsula to determine the rate of uplift over the last 5,000 years. The researchers will also analyze the structure of the beaches using ground-penetrating radar and the characteristics of beach sediments to understand how sea-level rise and past climate changes are recorded in beach deposits. The benefits of these new records will be threefold: (1) they will help determine the natural variability of the Antarctic Ice Sheet and relative sea level (2) they will provide new insight about uplift and the structure of the Earth's interior; and 3) they will help researchers refine the methods used to determine the age of geologic deposits. The study results will be shared in outreach events at K-12 schools and with visitors of the Santa Barbara Natural History Museum. Three graduate students will be supported through this project. Technical descriptionPaleo sea-level data is critical for reconstructing the size and extent of past ice sheets, documenting increased uplift following glacial retreat, and correcting gravity-based measurements of ice-mass loss for the impacts of post-glacial rebound. However, there are only 14 sites with relative sea-level data for Antarctica compared to over 500 sites used in a recent study of the North American Ice-Sheet complex. The purpose of this project is to use optically stimulated luminescence to date a series of newly discovered raised beaches along the eastern Antarctic Peninsula and an already known, but only preliminarily dated, series of raised beaches in the South Shetland Islands. Data to be collected at the raised beaches include the age and elevation, ground-penetrating radar profiles, and the roundness of cobbles and the lithology of ice-rafted debris. The study will test three hypotheses: (1) uplift rates have increased in modern times relative to the late Holocene across the Antarctic Peninsula, (2) the sea-level history at the northern tip of the Antarctic Peninsula is distinctly different than that of the South Shetland Islands, and (3) cobble roundness and the source of ice-rafted debris on raised beaches varied systematically through time reflecting the climate history of the northern Antarctic Peninsula.