RECENT ADVANCES IN ANALYTICAL INSTRUMENTATION HAVE GENERATED A LARGE VOLUME OF HIGH-PRECISION ISOTOPIC DATA IN EARLY SOLAR SYSTEM MATERIALS. THE KINETIC ISOTOPIC EFFECTS MEASURED IN METEORITES ARE PARTICULARLY IMPORTANT AS THEY SERVE AS FINGERPRINTS OF PROCESSES THAT OCCURRED DURING THEIR FORMATION AND EVOLUTION. FOR EXAMPLE MASS-DEPENDENT FRACTIONATION EFFECTS IN MG SI AND O ISOTOPES IN CAIS ARE CONSIDERED AS INDICATORS OF THE EVAPORATION IN LOW-PRESSURE CONDITIONS WHILE FRACTIONATED LI AND MG ISOTOPES IN ZONED CRYSTALS FROM MARTIAN METEORITES AND LUNAR SAMPLES IMPLY THE DIFFUSION-DRIVEN ELEMENTAL TRANSPORT DURING MELT CRYSTALLIZATION. HOWEVER QUANTITATIVE INTERPRETATION OF SUCH EFFECTS REQUIRES THEIR LABORATORY CALIBRATION WHICH IS VERY LIMITED AND THE COMMON THEME OF THE PROPOSED RESEARCH IS TO PROVIDE SUCH CALIBRATION EXPERIMENTS UNDER CONTROLLED CONDITIONS CLOSE TO THOSE IN NATURAL SYSTEMS.SPECIFICALLY WE WILL CONCENTRATE ON: (1) ISOTOPIC FRACTIONATION CAUSED BY EVAPORATION OF CAI-LIKE MATERIALS IN LOW-PRESSURE HYDROGEN TO ADDRESS CONDITIONS REQUIRED TO PRODUCE LARGE MASS-DEPENDENT FRACTIONATION EFFECTS IN MG SI AND O ISOTOPES MEASURED IN THE CAI MINERALS; THE RESULTS OF THE EXPERIMENTS WILL ALSO BE USED TO REEVALUATE MG ISOTOPIC MASS FRACTIONATION 'LAW' WHICH IS CRITICAL TO DETERMINE EXCESS OF 26MG DUE TO DECAY OF 26AL AND THUS FOR EARLY SOLAR SYSTEM CHRONOMETRY; (2) CHEMICAL FRACTIONATION OF REDOXSENSITIVE REES (CE EU YB) AND U AS FUNCTION OF FO2 AND TOTAL PRESSURE TO ADDRESS THE CONDITIONS REQUIRED FOR THEIR DEPLETIONS IN SOME FUN AND FUN-LIKE CAIS AND THE LACK OF SUCH IN MOST 'NORMAL' (NON-FUN) CAIS; DEPLETION IN U BY 100 IN FUN CAIS COMPARED TO 'NORMAL' CAIS IS PARTICULARLY IMPORTANT AS IT HAS PREVENTED USE OF THE PB-PB CHRONOMETER TO MEASURE THEIR ABSOLUTE AGES; (3) CHEMICAL AND ISOTOPIC ZONINGS IN THE LABORATORY-PRODUCED OLIVINE CRYSTALS BY COOLING OLIVINE COMPOSITION MELT AT DIFFERENT RATES AND FO2 TO DISTINGUISH BETWEEN CHEMICAL ZONING DUE TO A CRYSTAL GROWTH FROM CHEMICALLY EVOLVING MELT AND ZONING DUE TO INTERDIFFUSION OF MG AND FE IN OLIVINE; THE RESULTS OF THE EXPERIMENTS WILL BE USED TO PLACE CONSTRAINTS ON COOLING RATES AND THE CRYSTAL GROWTH RATE OF OLIVINE IN MARTIAN METEORITES AND LUNAR SAMPLES. SEVERAL OF THE PROPOSED TOPICS ON EVAPORATION OF CAI-LIKE MELTS HAVE BEEN PREVIOUSLY CARRIED OUT IN ISOTHERMAL VACUUM EXPERIMENTS. IT IS VERY IMPORTANT TO EXPAND THE EXPERIMENTAL CONDITIONS TO THOSE OF LOW-PRESSURE HYDROGEN RESEMBLING SOLAR NEBULA AND TO INCLUDE EFFECTS OF CRYSTALLIZATION DURING EVAPORATION. EXPERIMENTS WILL BE CONDUCTED IN A LOW-PRESSURE HYDROGEN (APPROX 10-4 BAR) FURNACE THAT WILL BE BUILD IN A VACUUM (LESS THAN 10-8 BAR) FURNACE AND IN A ONE-ATMOSPHERE GAS-MIXING FURNACES. THE RUN PRODUCTS WILL BE CHARACTERIZED USING A TESCAN LYRA3 FIB/FESEM (FOCUSED ION BEAM / FIELD EMISSION SCANNING ELECTRON MICROSCOPE) AT THE UNIVERSITY OF CHICAGO. ISOTOPIC COMPOSITION WILL BE MEASURED BY SOLUTION AND LASER-ABLATION ICPMS (INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY) AND BY HIGH-PRECISION SIMS (SECONDARY ION MASS SPECTROMETRY) AT THE UNIVERSITY OF CHICAGO UNIVERSITY OF WASHINGTON AND UCLA.THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE EMERGING WORLDS PROGRAM WHICH AIMS TO UNDERSTAND FORMATION AND EVOLUTION OF THE EARLY SOLAR SYSTEM MATERIALS AND FALLS IN THE SCOPE OF SEVERAL THEMES LISTED IN THE PROGRAM (E.G. LARGE-SCALE CHEMICAL AND ISOTOPIC FRACTIONATION PROCESSES; CHEMICAL AND PHYSICAL PROCESSING OF GAS DUST AND ICE).