9616072 Jacobsen This grant provides $128,493 as partial salary support for a technician responsible for oversight, maintenance and daily operation of the thermal ionization mass spectrometry (TIMS) facility at Harvard University. This is a Phase I technician support grant under the EAR/IF technician support sub-program. Establishment of this technical position at the Harvard TIMS lab will provide needed instrumental oversight and maintenance (there are 3 TIMS at Harvard) which will soon increase as the result of Harvard's decision to add an additional faculty member and a research associate, Roberta Rudnick and Paul Hoffman, respectively, whose research requires the use of TIMS for radiogenic isotopic analyses. Technical support will also greatly facilitate the PI's research on a variety of topics including, studies of the accretion and early history of the Earth based on measurement of the Hafnium-Tungsten isotopic system using negative ion TIMS (N-TIMS), studies of mantle geochemistry based on Neodymium/Samarium and Rubidium/Strontium isotopic analyses of Komatiites and high-MgO basalts, elemental analyses of the Platinum group elements (PGE) in basalts using N-TIMS, U/Pb geochronology as applied to lithospheric tectonics and use of Sr isotopes to infer paleo-surface processes. ***