Gas and Dust Measurements for Taylor Glacier and Taylor Dome Ice Cores

Abstract: New ice cores retrieved from the Taylor Glacier (Antarctica) blue ice area contain ice and air spanning the Marine Isotope Stage (MIS) 5-4 transition, a period of global cooling and ice sheet expansion. We determine chronologies for the ice and air bubbles in the new ice cores by visually matching variations in gas- and ice- phase tracers to preexisting ice core records. The chronologies reveal an ice age-gas age difference (Δage) approaching 10 ka during MIS 4, implying very low snow accumulation in the Taylor Glacier accumulation zone. A revised chronology for the analagous section of the Taylor Dome ice core (84 to 55 ka), located to the south of the Taylor Glacier accumulation zone, shows that Δage did not exceed 3 ka. The difference in Δage between the two records during MIS 4 is similar in magnitude but opposite in direction to what is observed at the Last Glacial Maximum. This relationship implies that a spatial gradient in snow accumulation existed across the Taylor Dome region during MIS 4 that was oriented in the opposite direction of the accumulation gradient during the Last Glacial Maximum.摘要：从南极泰勒冰川（Taylor Glacier）蓝冰区获取的新型冰芯，其封存的冰体与包裹气泡覆盖了海洋同位素阶段（Marine Isotope Stage，简称MIS）5至4的过渡时期——这是一段全球降温与冰盖扩张的时期。我们通过将气相示踪剂与冰相示踪剂的变化与已有的冰芯记录进行目视匹配，确定了该新型冰芯中冰体与气泡的年代序列。该年代序列显示，在MIS 4时期，冰龄与气龄的差值（Δage）接近10 ka，这意味着泰勒冰川积累区的降雪积累量极低。对位于泰勒冰川积累区以南的泰勒穹顶（Taylor Dome）冰芯对应区段（84至55 ka）的修订年代序列表明，其Δage未超过3 ka。MIS 4时期两份记录的Δage差值，其幅度与末次冰盛期（Last Glacial Maximum）观测到的结果相似，但方向相反。这一关系表明，在MIS 4时期，泰勒穹顶区域存在降雪积累的空间梯度，其取向与末次冰盛期的积累梯度截然相反。