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

科学界和公众对南极半岛和南极洲西部冰盖对全球变暖的潜在反应非常感兴趣。最近的观测表明，该地区正在经历迅速的变化，包括变暖，冰架解体，冰盖变薄和退缩。这些最近的变化需要考虑在一个较长的地质背景下，通过研究海洋沉积物接近南极西部和南极半岛冰盖。为此，我们已提交了IODP提案，目前正在等待安排，以钻探位于别林豪森海（太平洋）沉积物漂移的一系列地点。年代控制不精确，在很大程度上是由于缺乏有孔虫碳酸盐同位素分析，阻碍了古海洋学解释的沉积物芯从南大洋。在为预期的IODP考察做准备时，我们提出了一个“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要恢复的长层序。我们将研究在一个拟议的IODP站点（Pen-1）采集的活塞岩心PC 466，它是由英国南极调查局在RRS James Clark Ross上在2400 m水深的贝林豪森海（64 S，69 W）大陆隆起的沉积物漂移中发现的。这个10.5米的短沉积记录跨越了末次冰期（约70，000年），具有高沉积速率，并在元素组成（XRF）和磁化率方面表现出明显的千年尺度变化。我们对核心PC-466的目标有三个方面。1)开发一个精确的年龄模型，可用于与两个半球的其他海洋沉积物岩心和极地冰芯进行地层对比。2)利用冰筏碎屑研究冰盖的前进和后退。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了将传统的地层学和古海洋学工具应用于PC-466岩心的末次冰期（古气候学家和古海洋学家最了解的时期）是可能的，那么我们可以合理地相信，这种方法将适用于提案-732所设想的数千米的记录，并覆盖过去的几百万年。

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.