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: 9909803
• 负责人: Stefanie Brachfeld
• 金额: $ 6万
• 依托单位: University of Minnesota-Twin Cities
• 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 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9909803&HistoricalAwards=false
• 关键词: Quaternary; Glacial; History; Paleoenvironments; East

9909803BrachfieldThis 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.

9909803 Brachfield该奖项由极地计划办公室南极地质和地球物理计划提供，支持对普里兹湾和麦克罗伯逊大陆架进行多机构、国际（美国-澳大利亚）海洋地质和地球物理调查，该调查将在大约60天的时间内完成。乘坐RVIB NB航行帕尔默主要目的是利用通过卡斯滕和大型活塞取芯收集的沉积物芯，记录第四纪的气候和海洋变化。 将根据地震剖面法（Seabeam 2112和Bathy 2000）选择岩芯地点。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南极西部边缘沿着收集的数据，而来自更广阔的南极东部边缘的类似的广泛和高分辨率数据集却很少。该项目的目标包括：（1）建立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冰期和间冰期事件的沉积记录的假设，并评价东南极边缘这段沿着500公里的地区最大冰期的时间和范围。将利用高分辨率地震制图和对内陆架洼地沉积物取芯来重建全新世古环境。 在南极半岛和罗斯海的类似沉积环境中，沉积记录表明，全新世期间初级生产力和海冰范围存在千年和世纪尺度的变化，这与放射性碳分布的时间周期性有关，表明太阳变化可能在推动全新世气候变化中发挥作用。东南极边缘的类似高分辨率全新世记录将用于开发一套关于南部冰川和海洋系统对晚第四纪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东南极边缘对全球变暖的响应。 对普雷兹海峡-埃默里洼地地区的初步调查揭示了在先前更新世间冰期沉积的层序。 上全新世和下（未注明日期）硅质单元可以追溯到15 000平方公里的Prenchez海峡，但需要更多的海底下地震反射剖面，并在该地区密集取芯，以确定单元的空间分布和范围。 年代学工作将确定晚更新世期间南极东部边缘冰川海洋沉积的时间和持续时间。分析将侧重于详细的沉积学，地球化学，微体古生物学和古地磁技术。 这种多参数的方法是最有效的方法来提取一个有价值的古环境信号在这些冰川海洋沉积物。 这些研究结果有望大大促进对南极冰盖和海洋系统在最近的地质历史中的行为的理解。这些研究人员都具有在高纬度海洋环境中工作的多年经验，他们的组合将提供一个有效的团队来完成这个项目。 大学和学院教师（本项目的主要研究者）将监督参与项目各个阶段的本科生和研究生的组合，以便教育目标与项目的研究目标同步实现。