Revision of the Greenland Ice Sheet Program 2 (GISP2) Depth-Age Scale

本项目由大气科学部北极自然科学项目、南极冰川学项目和古气候项目联合资助。格陵兰冰盖计划2 （GISP2）的深度年龄尺度从全新世一直到威斯康辛州，每年的精确度在1%以内，因此对古气候界有很大的兴趣。研究人员已经使用并希望继续使用我们最有价值的古气候档案，GISP2和格陵兰冰芯项目（GRIP）冰芯，来校准来自其他材料的年表。由于GRIP岩心是同时钻探的，并且距离GISP2岩心很近（30公里），因此两个岩心之间的比较预计是相似的。然而，有些岩心片段有足够的变异性，年表受到质疑。这在冰芯和古气候群落中造成了混淆。这些错误的一个例子可以在南极的简单圆顶岩芯中看到。与GISP2年代学一样，simple Dome年代学基于年层数，但更深处的气体年代学基于与GISP2记录的相关性，从而延续了GISP2年代学中存在的错误。至关重要的是，重新审查GISP2的年表，并在可能的情况下解决任何差异。首席研究员将：1)使用自原始GISP2深度年龄完成以来获得的新火山记录作为更多校准的附加联络点；2)基于新的铍-10和碳-14结果对GISP2全新世深度年龄尺度进行了修正；3)根据最近的出版物，重新审视GISP2和GRIP冰芯之间存在差异的深度-年龄尺度区域。GISP2深度年龄尺度的修订将通过重新检查核心区域来完成，这些区域是由原始GISP2年代学完成后获得的新数据确定的。此外，GISP2和GRIP年表不同的核心区域将被重新检查。在与GRIP记录存在差异的情况下，目标不是调整GISP2年表，而是识别由于新数据而出现的任何明显错误，并在必要时进行调整，以获得最佳的GISP2年表。

Meese0220949This proposal is being jointly funded by the Arctic Natural Sciences Program, Antarctic Glaciology Program, and the Paleoclimate Program in the Division of Atmospheric Sciences. The Greenland Ice Sheet Project 2 (GISP2) depth-age scale is accurate within one per cent on an annual basis through the Holocene and into the Wisconsin and therefore has been of great interest to the paleoclimate community. Researchers have used, and want continue to use our most valuable paleoclimate archives, the GISP2 and the Greenland Ice Core Project (GRIP) ice cores, to calibrate chronologies from other materials. Because the GRIP core was drilled simultaneously and in close proximity (30 km) to the GISP2 core, comparison between the two cores was expected to be similar. However, there are segments of the cores where there is sufficient variability and the chronologies have been questioned. This has caused confusion within the ice coring and the paleoclimate communities. An example of these errors can be seen in the Antarctic Siple Dome core. Like the GISP2 chronology, the Siple Dome chronology is based on annual layer counts, but the gas age chronology deeper in the core is based on correlations with the GISP2 record perpetuating the errors that exist in the GISP2 chronology. It is critical that the GISP2 chronology be reexamined and any discrepancies be resolved, if possible. The Principal Investigator will: 1) use new volcanic records obtained since the completion of the original GISP2 depth-age as additional tie points for greater calibration; 2) revise the Holocene portion of the GISP2 depth-age scale based on the new Berylium-10 and Carbon-14 results; and 3) revisit areas of the depth-age scale where discrepancies exist between the GISP2 and GRIP ice cores based on a recent publication. Revision of the GISP2 depth-age scale will be accomplished by reexamining areas of the core that have been identified to be in error by new data that have come available since the completion of the original GISP2 chronology. Additionally, areas of the core where the GISP2 and GRIP chronologies vary will be reexamined. The goal in the cases where discrepancies exist with the GRIP record is not to adjust the GISP2 chronology, but to identify any errors that are now evident due to new data and make adjustments as necessary to obtain the best possible GISP2 chronology.