The second Greenland Ice Sheet Project (GISP II) in designed to retrieve and interpret an ice core from the ice sheet in central Greenland. This award supports a detailed study of the elemental composition of O2, N2 and Ar in trapped gases of the GISP II ice core. The results from this study will give a record of gas chemistry, back to at about 200 kyr B.P., which will be used to address a wide range of questions about the global biogeochemical cycles of carbon and oxygen. Studies of the paleoatmospheric O2 content will allow the testing of hypotheses invoked to explain Late Pleistocene variations in atmospheric CO2, as well as to examine other aspects of glacial carbon cycling. The record of Late Pleistocene 18O variations will also allow examination of aspects of the global scale interactions between the hydrosphere, biosphere, and atmosphere.
