Testing the stratigraphic and paleoenvironmental resolution of sediment drifts off West Antarctica for IODP drilling

南极半岛和西南极冰盖对全球变暖的潜在反应引起了科学界和公众的强烈兴趣。最近的观察表明，该地区正在经历快速变化，包括变暖、冰架解体、冰盖变薄和后退。需要在更长的地质背景下研究西南极和南极半岛冰盖附近的海洋沉积物，来考虑最近的这些变化。为此，我们已经提交了一份IODP提案，目前正在等待安排，以便在贝灵豪森海(太平洋)沉积物漂流上钻探一系列地点。不精确的年代学控制，在很大程度上是由于缺乏用于同位素分析的有孔虫碳酸盐，阻碍了对南大洋沉积物岩心的古海洋学解释。在为预期的IODP探险做准备时，我们提议进行一项“概念验证”研究，以应用主要的古海洋学和地层学方法来研究IODP将恢复的长层序。我们将研究在其中一个拟议的IODP站点(PEN-1)拍摄的活塞芯PC466，它是由英国南极调查局在詹姆斯·克拉克·罗斯号上发现的，是在贝灵豪森海(64s，69w)大陆隆起的沉积物漂流中2400米的水深发现的。这一10.5米的短沉积记录跨越了最后一次冰川时期(约70,000年)，沉积速率很高，元素组成(XRF)和磁化率都显示出明显的千年尺度变化。我们的核心PC-466有三个目标。1)建立了一个准确的年龄模型，可用于与两个半球的其他海洋沉积岩芯和极地冰芯进行地层对比。2)利用冰排碎屑研究冰盖的进退。3)重建地表水条件(温度、盐度、碳酸盐离子浓度和海冰)。如果我们成功地证明有可能将传统的地层学和古海洋学工具应用于PC-466岩芯的最后一次冰期(古气候学家和古海洋学家最了解的时间段)，那么我们可以合理地相信，这种方法将适用于提案-732设想的数千米的记录，并覆盖最后数百万年。

There is intense scientific and public interest in the potential response of the Antarctic Peninsula and West Antarctica ice sheets to global warming. Recent observations suggest that this region is undergoing rapid changes including warming, ice-shelf disintegration, ice-sheet thinning and retreat. These recent changes need to be considered in a longer geological context by studying marine sediments proximal to the West Antarctic and Antarctic Peninsula Ice-Sheets. Toward this end, we have submitted and IODP proposal, currently awaiting scheduling, to drill a serie of sites on sediment drifts located in the Bellinghausen Sea (Pacific Ocean). Imprecise chronological control, due in large part to lack of foraminiferal carbonate for isotopic analysis, has stymied paleoceanographic interpretations of sediment cores from the Southern ocean. In preparation for the anticipated IODP expedition, we propose a 'proof-of-concept' study to apply the main paleoceanographic and stratigraphic methods to be employed in the study of the long sequences to be recovered by IODP. We will study piston core PC466 taken at one of the proposed IODP Sites (Pen-1), It was recovered at a water depth of 2400m on a sediment drift on the continental rise in the Bellinghausen Sea (64S, 69W ) by the British Antarctic Survey on RRS James Clark Ross. This short sedimentary record of 10.5 meters spans the last glacial period (~70,000 years) with high sedimentation rates and exhibiting distinct millennial-scale variability in both elemental composition (XRF) and magnetic susceptibility. Our goals for core PC-466 are three-fold. 1) Develop an accurate age model that can be used for stratigraphic correlation to other marine sediment cores and polar ice cores in both hemispheres. 2) Study the advance and retreat of ice sheets using ice-rafted detritus. 3) Reconstruct surface water conditions (temperature, salinity, carbonate-ion concentration, and sea ice). If we are successful in demonstrating that it is possible to apply traditional stratigraphic and paleoceanographic tools to the last glacial period of core PC-466, (a time period that paleoclimatologists and paleoceanographers know best), then we can be reasonably confident that such approaches will work for thousands of meters of record envisaged by proposal-732 and covering the last several million years.