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

Meese 0220949该提案由北极自然科学计划、南极冰川学计划和大气科学部的古气候计划共同资助。格陵兰冰盖项目2（GISP 2）的深度年龄尺度是准确的百分之一，每年的基础上，通过全新世，并进入威斯康星州，因此一直有很大的兴趣，古气候界。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，GISP 2和格陵兰冰芯项目（GRIP）冰芯，以校准其他材料的年表。由于GRIP岩心是同时钻探的，并且与GISP 2岩心非常接近（30 km），因此预计两个岩心之间的比较相似。 然而，有些岩芯段存在足够的变异性，其年表受到质疑。这在冰核取芯和古气候学界造成了混乱。这些错误的一个例子可以在南极的Siple Dome核心中看到。与GISP 2年表一样，Siple Dome年表是基于年度地层计数，但核心深处的气体年龄年表是基于与GISP 2记录的相关性，从而使GISP 2年表中存在的错误永久化。如果可能的话，重新检查GISP 2年表并解决任何差异至关重要。主要研究者将：1）使用自完成原始GISP 2深度年龄以来获得的新火山记录作为更多校准的附加连接点; 2）根据新的铍-10和碳-14结果修订GISP 2深度年龄表的全新世部分; 3）根据最近的出版物重新访问GISP 2和GRIP冰芯之间存在差异的深度年龄表区域。GISP 2深度年龄表的修订工作将通过重新检查原始GISP 2年表完成后获得的新数据所确定的有错误的岩心区域来完成。此外，将重新审查GISP 2和GRIP年表不同的核心区域。在GRIP记录存在差异的情况下，目标不是调整GISP 2年表，而是确定由于新数据而出现的任何明显错误，并进行必要的调整，以获得最佳的GISP 2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.