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

摘要南极西部冰盖晚第四纪退缩的范围和模式是对该地区冰芯记录解释的重要控制因素，它对全球水收支（以海平面计算）、融水对海洋贡献的时间以及南北半球事件之间的同步（或缺乏同步）具有重要影响。该奖项支持对罗斯海西部冰川退缩年表的持续研究，并将该研究的区域覆盖范围扩大到罗斯海中东部。这项研究将使用一系列活塞、Kasten和抓取样本，这些样本来自1994年和1995年由莱斯大学、科罗拉多大学、博尔德大学和汉密尔顿学院的研究人员在RVIB N.B. Palmer上进行的研究巡航。岩心的各种物理和生物参数将被用于绘制环境随时间的变化，包括沉积物特性、有孔虫和硅藻的浓度。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从1994年之前收集的岩心以及1994年和1995年的巡航中获得了92个碳14日期（加上18个未决日期，全部基于加速器-质谱法）。重点将放在获得额外的放射性碳测年，并辅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作用。三个主要的研究问题是：1)末次盛冰期从罗斯海西部到东中部的接地线的位置是什么？从这个极限撤退的时间是什么？整个地区是否同步？撤退的速度是多少？2)是否有证据表明，在海洋同位素阶段（MIS） 2（可能是MIS 4）之前的某个时间，外部陆架岸的碳酸盐堆积史和罗斯海斜坡上的岩心在陆架断裂上形成了冰（Goodwin, person） ？commun。1996) ?3)在最新更新世和全新世的千年/世纪时间尺度上，罗斯海地区的古环境是怎样的？特别是，地表水生产力和海冰范围的变化历史是怎样的？

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 east- central 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 accelerator- mass-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 th e 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?