Collaborative Research: Trapped gas composition and the chronology of the Vostok ice core

高纬度深冰芯包含极地温度、大气尘埃负荷（和大陆干旱）、温室气体浓度、生物圈状况以及过去环境的其他基本属性的基本记录。如果要充分认识这些记录的重要性，就需要对它们进行准确的年表。测年的挑战刺激了轨道调整的努力。在这种方法中，人们在允许的范围内改变时间尺度，以优化古环境属性与日照曲线之间的匹配。由于直接日照强迫，理想的性质将随时间而变化。它将不受复杂的气候反馈和遥相关的影响，并将提供高信噪比的清晰记录。有人认为，强烈的O2/N2比的冰芯被困气体是这样一个属性，并提出证据表明，这种属性，其大气比几乎是恒定的，是当地夏季日照。 该奖项将支持一个项目，以分析在1 kyr的间隔从115 - 400 ka的东方冰芯的O2/N2比。将对Ar/N2、Ne/N2和重惰性气体比率进行辅助测量，以了解气泡封闭分馏及其在东方号捕获气体记录中的表现。 O2/N2的变化将与东方号的夏季日照相匹配，以获得东方号核心的高精度年表。 东方号和其他可验证的气候记录将被重新检查，以提高我们对更新世气候变化动力学的理解。

High latitude deep ice cores contain fundamental records of polar temperatures, atmospheric dust loads (and continental aridity), greenhouse gas concentrations, the status of the biosphere, and other essential properties of past environments. An accurate chronology for these records is needed if their significance is to be fully realized. The dating challenge has stimulated efforts at orbital tuning. In this approach, one varies a timescale, within allowable limits, to optimize the match between a paleoenvironmental property and a curve of insolation through time. The ideal property would vary with time due to direct insolation forcing. It would be unaffected by complex climate feedbacks and teleconnections, and it would give a clean record with high signal/noise ratio. It is argued strongly that the O2/N2 ratio of ice core trapped gases is such a property, and evidence is presented that this property, whose atmospheric ratio is nearly constant, is tied to local summertime insolation. This award will support a project to analyze the O2/N2 ratios at 1 kyr intervals from ~ 115-400 ka in the Vostok ice core. Ancillary measurements will be made of Ar/N2, and Ne/N2 and heavy noble gas ratios, in order to understand bubble close-off fractionation and its manifestation in the Vostok trapped gas record. O2/N2 variations will be matched with summertime insolation at Vostok to achieve a high-accuracy chronology for the Vostok core. The Vostok and other correlatable climate records will then be reexamined to improve our understanding of the dynamics of Pleistocene climate change.