Expedition Objective Research: Investigating Antarctic Cryosphere Changes at Wilkes Land During the Oligocene and Presumed "Stable" Icehouse World of the Late Miocene

南极洲的关键部分？由于缺乏该地区的高质量气候数据，该地区的气候和冰冻圈历史仍然不确定。特别是，沉积档案沉积在渐新世，其中包括？中？渐新世（一个气候-冰量变化放大的时期）和中新世晚期，冰盖的相对稳定性仍然存在高度争议，是破译南极洲气候历史的主要缺失部分。综合大洋钻探计划第318次远征的目的是调查南极洲的冰川历史，从温室世界，一个全球变暖的时代，几乎没有冰川冰，到冰屋世界，一个大陆规模的冰盖时代。威尔克斯地是了解这段历史的关键，因为数值模型表明，该地区是东南极洲最后一个冰川化的地区之一。这使得东南极洲的这一部分在过去对气候变化最敏感，在未来更容易受到气候变化的影响。这项研究有两个主要焦点。首先，确定时间冰盖和各种冰流到达南极海岸线在渐新世使用高分辨率的粒度记录，以确定冰筏碎片（IRD）的起源记录，使用Ar-Ar测年的角砾颗粒从IRD约束冰山的来源。第二，研究晚中新世（12-11万年BP）期间的海洋变暖事件，该事件似乎与Preniz湾300多公里的重大冰川退缩同步。这将通过开发成对的高分辨率稳定同位素和镁/钙比记录从底栖和可能的浮游有孔虫和有孔虫生物相从晚中新世地层从站点U1361，然后将它们与Prenchez湾记录。该项目的成果将首次提供来自南极洲附近一个地点的必要数据，以检验各种假设，并回答尚未解决的问题，这些问题涉及冰库世界开始期间（渐新世）和冰盖被认为相对稳定的时间间隔期间（晚中新世）南极冰盖的时间和范围。此外，这些结果也将是关键的气候模型在开发一个更好地了解冰盖动态在这些时间间隔。该项目的主要教育推广目标是通过开发一个本科生的研究和指导计划，为三个本科生和一个研究生，以激励和教育下一代南极研究人员。这与PI在社区和教育推广工作中的长期承诺是一致的。作为教育推广的一部分，PI将主持由海洋领导组织的巡航后视频会议，这些会议是为在探险期间参加视频会议的学校举办的。其他外联活动包括向全国六个主要博物馆进行介绍和动手示范。

Critical pieces of Antarctica?s climatic and cryospheric history remain uncertain owing to a lack of high quality climate data from this region. In particular, sedimentary archives deposited during the Oligocene, which includes the ?mid? Oligocene (a time of amplified climate-ice volume variability), and the late Miocene when the relative stability of the ice sheet is still highly debated, are major missing pieces in deciphering the climate history of Antarctica. The goal of Integrated Ocean Drilling Program Expedition 318 to Wilkes land was to investigate the glacial history of Antarctica from the Greenhouse World, a time of global warmth, with little to no glacial ice, to the Icehouse World, a time of continental size ice sheets. The Wilkes Land area is critical in understanding this history as numerical models suggest that this region was among the last areas of East Antarctica to become glaciated. This makes this part of East Antarctica the most sensitive to climate changes in the past and more vulnerable to future change. This research has two major foci. First, determining the timing when the ice sheet and various ice streams reached the Antarctic coastline during the Oligocene using high-resolution grain size records to identify ice rafted debris (IRD) provenance records using Ar Ar dating of hornblende grains from the IRD to constrain the source of icebergs. Second, examining an oceanic warming event during the Late Miocene (12-11 million years BP) that appears to be synchronous with a significant glacial retreat of over 300 km in Prydz Bay. This is will be accomplished by developing paired high-resolution stable isotope and Mg/ Ca ratio records from benthic and possibly planktonic foraminifers and foraminiferal biofacies from Late Miocene strata from Site U1361 and then correlate them to the Prydz Bay records. The results from this project will provide, for the first time, the requisite data from a site proximal to Antarctica to test hypotheses and answer yet unresolved questions related to the timing and extent of the Antarctic ice sheet during the start of the icehouse world (Oligocene) and during a time interval when the ice sheet was considered to be relatively stable (Late Miocene). Additionally, these results will also be key for climate modelers in developing a better understanding of ice sheet dynamics during these time intervals.The main educational outreach goal of this project is to inspire and educate the next generation of Antarctic researchers by developing an undergraduate research and mentoring program for three undergraduate students and one graduate student. This is in tune with a long-term commitment of the PI working in community and educational outreach efforts. As part of educational outreach, the PI will host post-cruise video conferences being organized by Ocean Leadership for schools that participated in video conferencing during the expedition. Additional outreach activities include giving presentations and hands-on demonstrations to six major museums across the country.