9506469 Bird The research program will investigate hydrothermal chronology of the 55 Ma to 35 Ma epizonal plutonic complexes at Kap Gustav Holm, Imilik, Kialineq, and Nualik in central East Greenland. The objective is to determine temporal variations in the stable isotope composition of Eocene meteoritic water caused by climatic and geographic changes related to initiation of the Iceland mantle plume and crustal rifting between Greenland and Eurasia. With support from the Danish Lithosphere Center samples for this study were collected from the Kap Gustav Holm complex in the summer of 1994 and samples from the remaining plutonic centers will be collected during the summer of 1995. The research is based on determinations of radiometric (40Ar/39Ar) ages and oxygen and hydrogen isotope compositions of amphiboles and K-micas from the plutonic centers. Laboratory studies will initially focus on phase relations, compositions, and parageneses of hydrothermal minerals and will be completed in approximately 1.5 years. The remainder of the project will involve synthesis and analysis of the data, and evaluation of our findings in terms of climate changes that accompanied the paleogeographic evolution of the North Atlantic Ocean basins and gateways.
