Late Quaternary History of the Western and East-Central Ross Sea, Antarctica: A Contribution to the West Antarctic Ice Sheet Initiative

OPP 9614287 Andrews OPP 9615046 Leventer南极西部冰盖第四纪晚期退缩的范围和模式是解释该地区冰芯记录的重要控制因素，它对全球水收支(以海平面计算)、融水向海洋贡献的时间以及南北半球事件之间的同步性(或缺乏同步性)具有重要的影响。该奖项支持对罗斯海西部冰川消退年表的持续研究，并扩大这项研究的面积范围，将罗斯海中东部包括在内。这项研究将使用一系列活塞、卡斯滕，并从1994年和1995年在RVIB N.B.Palmer上进行的研究巡航中抓取样本，这些样本来自莱斯大学、科罗拉多大学博尔德分校和汉密尔顿学院的研究人员。岩心的各种物理和生物参数将被用来绘制环境随时间的变化图，重点是沉积物性质、有孔虫和硅藻。目前，汉密尔顿学院和科罗拉多大学博尔德分校的研究小组已经从1994年前收集的岩心以及1994年和1995年的巡航中获得了92个碳14年代(加上18个悬而未决的日期，全部基于加速器质谱仪)。将把重点放在获得更多的放射性碳测年上，并辅之以其他几种年代学方法，包括：火山灰的来源和年龄、孤立珊瑚的铀系列测年和氨基酸消旋。三个主要的研究问题是：1)在最后一次从罗斯海西部到中东部的冰川盛期，基准线的位置是什么，从这个界限退缩的时间是什么，整个地区是同步的，退缩的速度是多少？2)从外陆架海岸和罗斯海斜坡岩心的碳酸盐聚集史中是否有证据表明，冰在海洋同位素阶段(MIS)2之前的某个时间搁浅在陆架破裂上，可能是在MIS4(古德温，个人)。通行证。3)在最新更新世和全新世期间，罗斯海地区在千年/世纪时间尺度上的古环境是什么？特别是，地表水生产力和海冰面积变化的历史是什么？

OPP 9614287 Andrews OPP 9615046 Leventer Abstract The late Quaternary extent and pattern of retreat of the West Antarctic Ice Sheet is an important control on interpretation of ice core records from the region and it has important ramification regarding the global water budget (in sea level terms), the timing of meltwater contributions to the ocean, and the synchrony (or lack thereof) between events in the Northern and Southern Hemispheres. This award supports continued research on the chronology of ice retreat from the western Ross Sea and an extension of areal coverage for this research to include the eastcentral Ross Sea. The study will use a series of piston, Kasten, and grab samples from research cruises in 1994 and 1995 on the RVIB N.B. Palmer by researchers from Rice University, University of Colorado, Boulder, and Hamilton College. Various physical and biological parameters of the cores will be used to map changes in the environments over time with a concentration on sediment properties, foraminifera, and diatoms. At this time, ninety-two carbon-14 dates (plus 18 pending dates, all based on acceleratormass-spectrometry) have been obtained from cores collected prior to 1994 and from the 1994 and 1995 cruises by the research groups at Hamilton College and the University of Colorado, Boulder. Emphasis will be placed on obtaining additional radiocarbon dates supplemented by several other chronological methods including: sources and ages of volcanic ashes, uranium-series dating of solitary corals, and amino acid racemization. The three major research questions are: 1) What was the position of the grounding line during the Last Glacial Maximum from the western to east-central Ross Sea and what was the timing of retreat from this limit, was it synchronous across the region, and what was the rate of retreat ? 2) Is there evidence from the history of carbonate accumulation on the outer shelf banks, and from cores on the slope of the Ross Sea that the ice was grounded on the shelf break at some time prior to marine isotope stage (MIS) 2, possibly at MIS 4 (Goodwin, person. commun. 1996)? 3) What are the paleoenvironments in the areas of the Ross Sea at the millenial/century time-scales during the latest Pleistocene and the Holocene? In particular, what is the history of changes in surface water productivity and sea ice extent?