Polar ice cores constitute excellent archives of past environmental conditions and provide us with glimpses into the Earth’s climatic history over hundreds of thousands of years. For the past two decades, noble gases, used as conservative tracers, have played a substantial role in extracting information from these archives. Noble gas analysis can be performed on two types of ice core samples. F...

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Overview of hydrogeologic tracer experiments and concepts. . . . . . . . . . . . . . . . . . . . . . . . . . 1 Expedition 327 tracer experiments. . . . . . . . . . 3 Tracer monitoring . . . . . . . . . . . . . . . . . . . . . . . 7 Summary of Expedition 327 tracer injection operations. . . . . . . . . . . . . . . . . . . . . . . . . ...