Quaternary Glacial History and Paleoenvironments of the East Antarctic Margin

南极东部边缘第四纪冰川历史与古环境

• 批准号: 9909793
• 负责人: Patricia Manley
• 金额: $ 6.9万
• 依托单位: Middlebury College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9909793&HistoricalAwards=false
• 关键词: Quaternary; Glacial; History; Paleoenvironments; East

9909793ManleyThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a multi-institutional, international (US - Australia) marine geologic and geophysical investigation of Prydz Bay and the MacRobertson Shelf, to be completed during an approximately 60-day cruise aboard the RVIB N.B. Palmer. The primary objective is to develop a record of climate and oceanographic change during the Quaternary, using sediment cores collected via kasten and jumbo piston coring. Core sites will be selected based on seismic profiling (Seabeam 2112 and Bathy2000). Recognition of the central role of the Antarctic Ice Sheet to global oceanic and atmospheric systems is based primarily on data collected along the West Antarctic margin, while similar extensive and high resolution data sets from the much more extensive East Antarctic margin are sparse. Goals of this project include (1) development of a century- to millennial-scale record of Holocene paleoenvironments, and (2) testing of hypotheses concerning the sedimentary record of previous glacial and interglacial events on the shelf, and evaluation of the timing and extent of maximum glaciation along this 500 km stretch of the East Antarctic margin. High-resolution seismic mapping and coring of sediments deposited in inner shelf depressions will be used to reconstruct Holocene paleoenvironments. In similar depositional settings in the Antarctic Peninsula and Ross Sea, sedimentary records demonstrate millennial- and century- scale variability in primary production and sea-ice extent during the Holocene, which have been linked to chronological periodicities in radiocarbon distribution, suggesting the possible role of solar variability in driving some changes in Holocene climate. Similar high-resolution Holocene records from the East Antarctic margin will be used to develop a circum-Antarctic suite of data regarding the response of southern glacial and oceanographic systems to late Quaternary climate change. In addition, these data will help us to evaluate the response of the East Antarctic margin to global warming. Initial surveys of the Prydz Channel - Amery Depression region reveal sequences deposited during previous Pleistocene interglacials. The upper Holocene and lower (undated) siliceous units can be traced over 15,000 km2 of the Prydz Channel, but more sub-bottom seismic reflection profiling in conjunction with dense coring over this region is needed to define the spatial distribution and extent of the units. Chronological work will determine the timing and duration of previous periods of glacial marine sedimentation on the East Antarctic margin during the late Pleistocene. Analyses will focus on detailed sedimentologic, geochemical, micropaleontological, and paleomagnetic techniques. This multi-parameter approach is the most effective way to extract a valuable paleoenvironmental signal in these glacial marine sediments. These results are expected to lead to a significant advance in understanding of the behavior of the Antarctic ice-sheet and ocean system in the recent geologic past.The combination of investigators, all with many years of experience working in high latitude marine settings, will provide an effective team to complete the project. University and College faculty (Principal Investigators on this project) will supervise a combination of undergraduate and post-graduate students involved in all stages of the project so that educational objectives will be met in tandem with the research goals of the project.

该奖项由极地方案办公室南极地质和地球物理方案提供，支持对普里兹湾和麦克罗伯逊陆架进行多机构、国际(美国-澳大利亚)海洋地质和地球物理调查，该调查将在RVIB N.B.Palmer号上进行约60天的巡航。主要目标是利用卡斯滕和巨型活塞取心收集的沉积物岩心，记录第四纪期间的气候和海洋变化。将根据地震剖面图(SeaBeam 2112和Bathy2000)选择核心地点。对南极冰盖对全球海洋和大气系统的中心作用的认识主要是基于沿西南极边缘收集的数据，而从更广阔的东南极边缘收集的类似的广泛和高分辨率的数据集很少。该项目的目标包括：(1)建立一个世纪至千年尺度的全新世古环境记录；(2)检验有关大陆架上以前的冰川和间冰期事件的沉积记录的假设，以及评估沿南极东部边缘500公里的这一段最大冰川的时间和程度。将使用高分辨率地震填图和沉积在内陆架凹陷的沉积物取心来重建全新世古环境。在南极半岛和罗斯海类似的沉积环境中，沉积记录显示了全新世期间初级生产力和海冰面积的千年级和百年级变异性，这与放射性碳分布的年代性周期有关，这表明太阳变异性可能在推动全新世气候变化方面发挥了作用。将利用东南极边缘的类似高分辨率全新世记录，编制一套关于南部冰川和海洋系统对第四纪晚期气候变化的反应的环南极数据。此外，这些数据将有助于我们评估南极东部边缘对全球变暖的反应。对普里兹海峡-阿莫利凹陷地区的初步调查显示，在以前的更新世间冰期沉积了层序。在15,000平方公里的普里兹海峡上可以追踪到上全新世和下(未测年)硅质单元，但需要更多的海底地震反射剖面，并结合该地区的密集取心来确定这些单元的空间分布和范围。年代学工作将确定晚更新世期间东南极边缘以前冰川海洋沉积的时间和持续时间。分析将集中在详细的沉积学、地球化学、微古生物和古地磁技术上。这种多参数方法是从这些冰川海洋沉积物中提取有价值的古环境信号的最有效的方法。这些结果有望大大提高对南极冰盖和海洋系统在最近地质历史中的行为的理解。具有多年在高纬度海洋环境中工作经验的调查人员的组合将为完成该项目提供一个有效的团队。大学和学院的教职员工(该项目的首席调查人员)将监督参与该项目所有阶段的本科生和研究生，以使教育目标与该项目的研究目标同步实现。