Constraining Plio-Pleistocene West Antarctic Ice Sheet Behavior from the Ohio Range and Scott Glacier

模拟西南极冰盖（WAIS）范围随时间的波动是冰川学界的一个主要目标。这些模型将为未来海平面变化的预测提供重要基础，因此这项工作具有很大的社会意义。上新世中期的时间间隔特别令人感兴趣，因为这是全球气温变暖和大气CO2浓度可能高于目前水平的最近时期。然而，在WAIS波动的观测约束年龄比末次冰期最大是罕见的。研究人员建议从俄亥俄州山脉和斯科特冰川收集地球化学数据，以量化WAIS高度过去的变化。 有限的宇宙成因核素数据与一个模型大致一致，该模型表明上新世WAIS的海拔和体积比现在小，WAIS崩溃是常见的。PI将使用地质观测和来自多个地点和多个海拔的基岩样本（包括冰下样本）的宇宙成因核素浓度，以“量油尺”方式限制WAIS冰量变化。从拟议的研究中获得的数据将提供数据冰盖模型比较的目标，以准确地描述上新世更新世和未来的WAIS行为。作为该项目的一部分，研究人员将与自然历史博物馆和哈佛地球行星科学系合作，开发一个展览，该展览将成为博物馆最近开放的地球和行星科学画廊的一部分。该项目包括指导一名女研究生和一名女本科生。

Modeling fluctuations in the extent of the West Antarctic Ice Sheet (WAIS) over time is a principal goal of the glaciological community. These models will provide a critical basis for predictions of future sea level change, and therefore this work great societal relevance. The mid-Pliocene time interval is of particular interest, as it is the most recent period in which global temperatures were warmer and atmospheric CO2 concentrations may have been higher than current levels. However, observational constraints on fluctuations in the WAIS older than the last glacial maximum are rare. The investigators propose to collect geochemical data from the Ohio Range and Scott Glacier to quantify past variability in the height of the WAIS. Limited available cosmogenic nuclide data are broadly consistent with a model indicating that Pliocene WAIS elevations and volumes were smaller than at present, and that WAIS collapse was common. The PIs will use geologic observations and cosmogenic nuclide concentrations from bedrock samples at multiple locations and at multiple elevations, including sub-ice samples, to constrain WAIS ice volume changes in a "dipstick" like fashion. Data obtained from the proposed research will provide targets for data-ice sheet model comparisons to accurately characterize Plio-Pleistocene and future WAIS behavior. As part of this project, the investigators will work with the Natural History Museum and the Earth & Planetary Science department at Harvard to develop an exhibit that will become part of the Museum's recently opened Earth and Planetary Science Gallery. The project involves mentoring of a female graduate student as well as an undergraduate student.