Investigating Early Miocene Sub-ice Volcanoes in Antarctica for Improved Modeling and understanding of a Large Magmatic Province

预测未来海平面上升需要更好地了解格陵兰和南极冰盖的变化动态。更好地了解冰盖过去历史的一种方法是从过去地质时期的内陆冰中获得记录，特别是在南极洲，世界？世界上最大的冰原。这样的记录非常罕见，可以在横贯南极山脉中部的拉戈尔塞山脉的火山露头处获得。 现在暴露在拉戈尔塞山脉内的火山在东南极冰盖下爆发，收集的数据将记录过去冰盖的厚度。 此外，这些信息将用于确定影响冰盖稳定性的冰盖底部的热条件。该项目还将调查南极洲火山活动的起源以及与西南极裂谷系的联系。 WARS是一个广阔的扩展（即拉伸）大陆地壳区域，类似于东非的发现，火山活动分布广泛，寿命长（6500万年到目前活跃），尽管经过50多年的研究，南极洲火山活动和裂谷的根本原因仍然存在激烈的争论。因此，该奖项的结果也可能影响整个西南太平洋地区海洋火山活动的研究（例如，新西兰和澳大利亚），在那里，具有相似成分和年龄的火山区被共同的岩浆来源和过程联系在一起。该领域的计划包括一名研究生，他将从事岩石学数据的收集，分析和解释，作为他/她的硕士项目的一部分。提供的经验和专业分析培训将提高学生的质量？的研究和优化他们的机会，为他们的未来。拟议的工作促进教师和学生的国家和国际合作，包括与多用户设施，提供先进的技术指导理科学生的工作。研究结果将在同行评审的期刊、科学会议上的公开演讲和外联活动中广泛传播。岩石学和地球化学数据将通过极地岩石储存库传播给社区。冰下喷发火山岩的研究已经发展到现在是建立精确的地球化学数据的最有力的替代方法。快照？包括多个关键的冰参数。这些数据应包括对冰厚、表面高度和稳定性的测量，这些数据将用于核实或否定已公布的将冰动态与海平面变化联系起来的半经验模型。除了确定火山形成期间南极东部是否有冰外，还将利用数据，结合使用40 Ar/39 Ar测年法的精确的新地质年代学，推导出同时代的冰厚度、表面海拔和基底热状况。从标准地球化学特征（主要，微量元素和Sr，Nd，Pb，O同位素）的测量推断将被用来调查火山和最近发现的冰下脊下东南极冰，这可能是一个裂谷侧翼隆起之间的可能关系。该山脊从未被取样，没有日期，其意义也不确定。 这些数据将提供有关南极大陆这一大部分被冰覆盖且知之甚少的地区之下的地球深部和地球动力学过程的重要新信息。

Predictions of future sea level rise require better understanding of the changing dynamics of the Greenland and Antarctic ice sheets. One way to better understand the past history of the ice sheets is to obtain records from inland ice for past geological periods, particularly in Antarctica, the world?s largest remaining ice sheet. Such records are exceedingly rare, and can be acquired at volcanic outcrops in the La Gorce Mountains of the central Transantarctic Mountains. Volcanoes now exposed within the La Gorce Mountains erupted beneath the East Antarctic ice sheet and the data collected will record how thick the ice sheet was in the past. In addition, information will be used to determine the thermal conditions at the base of the ice sheet, which impacts ice sheet stability. The project will also investigate the origin of volcanic activity in Antarctica and links to the West Antarctic Rift System (WARS). The WARS is a broad area of extended (i.e. stretched) continental crust, similar to that found in East Africa, and volcanism is wide spread and long-lived (65 million years to currently active) and despite more than 50 years of research, the fundamental cause of volcanism and rifting in Antarctica is still vigorously debated. The results of this award therefore also potentially impact the study of oceanic volcanism in the entire southwestern Pacific region (e.g., New Zealand and Australia), where volcanic fields of similar composition and age have been linked by common magma sources and processes. The field program includes a graduate student who will work on the collection, analysis, and interpretation of petrological data as part of his/her Masters project. The experience and specialized analytical training being offered will improve the quality of the student?s research and optimize their opportunities for their future. The proposed work fosters faculty and student national and international collaboration, including working with multi-user facilities that provide advanced technological mentoring of science students. Results will be broadly disseminated in peer-reviewed journals, public presentations at science meetings, and in outreach activities. Petrologic and geochemical data will be disseminated to be the community through the Polar Rock Repository.The study of subglacially erupted volcanic rocks has been developed to the extent that it is now the most powerful proxy methodology for establishing precise ?snapshots? of ice sheets, including multiple critical ice parameters. Such data should include measurements of ice thickness, surface elevation and stability, which will be used to verify, or reject, published semi-empirical models relating ice dynamics to sea level changes. In addition to establishing whether East Antarctic ice was present during the formation of the volcanoes, data will be used to derive the coeval ice thicknesses, surface elevations and basal thermal regime(s) in concert with a precise new geochronology using the 40Ar/39Ar dating method. Inferences from measurement of standard geochemical characteristics (major, trace elements and Sr, Nd, Pb, O isotopes) will be used to investigate a possible relationship between the volcanoes and the recently discovered subglacial ridge under the East Antarctic ice, which may be a rift flank uplift. The ridge has never been sampled, is undated and its significance is uncertain. The data will provide important new information about the deep Earth and geodynamic processes beneath this mostly ice covered and poorly understood sector of the Antarctic continent.