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

这项提议由北极自然科学计划、南极冰川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(GISP2)的深度-年龄标尺从全新世到威斯康星州每年的精确度都在百分之一以内，因此引起了古气候界的极大兴趣。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，根据其他材料校准年表。由于GRIP岩芯是同时钻探的，而且距离GISP2岩芯很近(30公里)，预计两个岩芯之间的比较将是相似的。然而，有些岩心的部分有足够的可变性，年表受到了质疑。这在冰芯和古气候社区内造成了混乱。这些错误的一个例子可以在南极Siple Dome核心看到。与GISP2年表一样，Siple Dome年表是基于每年的地层计数，但更深处的气体年龄年表是基于与GISP2记录的相关性，从而使GISP2年表中存在的误差永久化。如果可能，重新审查GISP2年表并解决任何差异是至关重要的。首席调查员将：1)使用自完成最初的GISP2深度年龄以来获得的新的火山记录作为额外的连接点，以便进行更大的校准；2)根据新的Berylium-10和Carbon-14结果修订GISP2深度年龄表的全新世部分；以及3)根据最近的一份出版物，重新审查GISP2和GRIP冰芯之间存在差异的深度-年龄表区域。对GISP2深度-年代表的修订将通过重新检查自最初的GISP2年表完成以来获得的新数据已查明有错误的核心区域来完成。此外，还将重新检查GISP2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GISP2年表，而是识别由于新数据而出现的任何错误，并根据需要进行调整，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.