An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120-800 ka
An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120-800 ka
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DOI：
10.5194/cp-9-1715-2013
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发表时间：
2013-01-01
影响因子：
4.3
通讯作者：
Wolff, E.
中科院分区：
文献类型：
--
作者：
Bazin, L.;Landais, A.;Wolff, E.
一个准确和连贯的年代学框架对于解释从极地深层冰芯获得的气候和环境记录至关重要。到目前为止，一个通用的冰芯年龄表是基于逆测年方法（Datice）开发的，该方法将冰川学建模与覆盖过去50 ka（数千年前）的4个冰芯之间的绝对和地层标记相结合（Lemieux-Dudon等人，2010年）。在本文中，与Veres等人（2013）的配套文件一起，我们使用改进版本的Datice工具将这项工作扩展到800 ka，用于NGRIP，TALDICE，EDML，Bostok和EDC冰芯。AICC 2012年（南极冰芯年表2012）年表包括许多新的气体和冰地层联系，以及改进的背景和相关的变化情况的评估。本文集中在120-800 ka之间的长时间尺度。在这个框架内，新的测量三角洲O-18（大气压）超过海洋同位素阶段（MIS）11-12 EDC和完整的三角洲O-18（大气压）记录的TALDICE冰芯允许我们获得额外的轨道气体年龄的限制。在AICC 2012中实施之前，已经验证了不同轨道推断年龄（从δ O-18（atm）、δ O-2/N-2和空气含量）的一致性。新的年代学现在独立于其他档案，只有很小的差异，大部分时间在Datice计算的原始不确定性范围内，与以前的冰芯参考年龄尺度EDC 3，Dome F年代学相比，或者使用洞穴和甲烷之间的比较。例如，AICC 2012和EDC 3之间的最大偏差（5.4 ka）在MIS 12附近获得。尽管围绕MIS 5的时间限制进行了重大修改，现在独立于AICC 2012中的洞穴记录，但终止II的日期非常接近EDC 3的日期。
An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice), combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present) (Lemieux-Dudon et al., 2010). In this paper, together with the companion paper of Veres et al. (2013), we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012) chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120-800 ka. In this framework, new measurements of delta O-18(atm) over Marine Isotope Stage (MIS) 11-12 on EDC and a complete delta O-18(atm) record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from delta O-18(atm), delta O-2/N-2 and air content) has been verified before implementation in AICC2012. The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka) is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.