This award provides one-half the funding necessary to modernize four older generation mass spectrometers at the Department of Terrestrial Magnetism of the Carnegie Institution of Washington (DTM-CIW). DTM-CIW is committed to providing the remaining funds needed for the upgrade. The Department of Terrestrial Magnetism carries out research projects in isotope geochemistry of the Earth's crust and mantle regions. The research is carried out by in-house geochemists and through a program of visiting scientists and research students. The improved performance of the upgraded mass spectrometers will enhance the capabilities of this user group to explore new analytical techniques in solid earth geochemistry.