THE ABUNDANCES AND ISOTOPIC COMPOSITION OF HYDROGEN IN GLASSES&MINERALS FROM CHONDRULES AND CAIS CAN POTENTIALLY PROVIDE INFORMATION ON THE IMMEDIATE ENVIRONMENT IN WHICH THEY FORMED AND/OR SUBSEQUENT MODIFICATION IN THEIR PARENT BODIES. IN THE INNER SOLAR SYSTEM, END MEMBER VOLATILE SOURCES INCLUDE THE SOLAR NEBULA GAS AND WATER ICE; THESE TWO SOURCES HAVE D/H RATIOS THAT DIFFER BY UP TO AN ORDER OF MAGNITUDE, AND ARE ALSO CHARACTERIZED BY VERY DIFFERENT O ISOTOPE COMPOSITIONS. ADDITIONALLY, COUPLED DATA ON DEGREE OF HYDRATION AND O ISOTOPE COMPOSITIONS OF CHONDRULES AND CAIS CAN POTENTIALLY IDENTIFY OPEN-SYSTEM BEHAVIOR IN PHASES THAT ARE USED FOR AL-MG, PB-PB, SM-ND AND HF-W CHRONOMETRY. OBJECTIVES: WE WILL EXAMINE CHONDRULES AND CAIS IN THE MOST PRIMITIVE (I.E., THE LEAST METAMORPHOSED AND AQUEOUSLY ALTERED) CO, CM, CR AND CV CARBONACEOUS CHONDRITES, AND THE ORDINARY CHONDRITES SEMARKONA, AND MET00526, TO DETERMINE IF THEY (A) PRESERVE EVIDENCE FOR VOLATILES INCORPORATED FROM THE SOLAR NEBULA, POTENTIALLY RECORDING THE PARTIAL PRESSURE OF HYDROGEN DURING THEIR FORMATION; AND (B) RECORD OPEN-SYSTEM BEHAVIOR FOR H, O IN THEIR PARENT BODIES. NEBULAR SIGNATURES CAN BE OVERPRINTED BY LATER INTERACTIONS WITH LOW-TEMPERATURE, H2O-RICH FLUIDS IN CHONDRITE PARENT BODIES, ACCOMPANIED BY HYDRATION AND FORMATION OF MOLECULAR H2O IN GLASS THAT IS FAR IN EXCESS OF THE H2O/OH RATIO TYPICAL OF QUENCHED HIGH-TEMPERATURE MELTS. THIS EXCESS MOLECULAR H2O IS READILY OBSERVED BY FTIR (SO MUCH SO THAT IT HAS FORMED THE FOUNDATION OF AN H2O-DIFFUSION-BASED DATING METHOD FOR OBSIDIAN TOOLS IN ARCHAEOLOGY). WE WILL USE SEM, EPMA, SIMS, FTIR AND RAMAN SPECTROSCOPY TO FOCUS ON DOCUMENTING THE RELATIONSHIP BETWEEN CONCENTRATIONS AND ISOTOPIC COMPOSITIONS OF H AND O IN CHONDRULES AND CAIS, AND THE H2O/OH RATIO IN CHONDRULE GLASSES, IN THE LEAST ALTERED AND METAMORPHOSED CHONDRITES, IN ORDER TO DETERMINE THE SOURCES OF HYDROGEN PRESENT IN THE EARLIEST INNER SOLAR SYSTEM. OUR ULTIMATE AIM IS THE DETECTION OF NEBULAR H IN CHONDRULES AND/OR CAIS. THIS WILL BE CHALLENGING AS NOT ONLY DO WE EXPECT CONCENTRATIONS TO BE LOW (THOUGH LIKELY WITHIN THE SIMS DETECTION LIMITS OF OUR ~0.1 PPM), BUT WE MUST ALSO EXCLUDE THE POTENTIAL OVERPRINTING BY THERMAL METAMORPHISM AND/OR AQUEOUS ALTERATION. THIS STUDY WILL PROVIDE CONSTRAINTS ON THE VARIOUS MODELS THAT EXIST TO EXPLAIN CHONDRULE AND CAI FORMATION, AND THE SOURCES OF ALTERING FLUIDS AND THE MECHANISMS OF FLUID-ROCK INTERACTION IN THE CHONDRITES. IN PAST WORK, WE HAVE DEMONSTRATED A UNIQUE ABILITY TO DETECT VERY LOW LEVELS OF HYDROGEN SILICATE MINERALS AND GLASSES BY SIMS, WITH DETECTION LIMITS BETTER THAN 0.1 PPM. ADDITIONALLY, OUR PRIOR WORK ON LUNAR VOLCANIC GLASSES AND MELT INCLUSIONS HAS DEMONSTRATED THAT WE CAN OBTAIN RELIABLE DATA ON H ISOTOPES AT TOTAL H CONCENTRATIONS<0.6 PPM (5.4 PPM H2O), AND SPATIALLY-RESOLVED ANALYSES OF HYDROGEN ISOTOPES AT THE MICRON SCALE OBTAINED BY SCANNING ION IMAGING SIMS. WE ARE THUS IN THE BEST POSSIBLE POSITION TO ADDRESS THE PROBLEM OF IDENTIFYING AND CHARACTERIZING THE VOLATILE SIGNATURES OF THE HIGH-TEMPERATURE COMPONENTS IN CARBONACEOUS CHONDRITES. RELEVANCE: THIS STUDY WILL ADDRESS SEVERAL OBJECTIVES OF THE EMERGING WORLDS PROGRAM, INCLUDING: (1) PROTOPLANETARY DISK FORMATION AND EVOLUTION, (2) NEBULAR TRANSPORT MECHANISMS, (3) LARGE-SCALE CHEMICAL AND ISOTOPIC FRACTIONATION PROCESSES, (4) CHEMICAL PROCESSING OF GAS, DUST AND ICE, (5) THE CHEMICAL PROPERTIES OF ANCIENT MATERIALS (CAIS, CHONDRULES), (6) EARLY THERMAL AND CHEMICAL PROCESSES OCCURRING ON SMALL BODIES, AND (7) PROCESSES THAT OCCUR ON SOLAR-SYSTEM BODIES DURING THE PERIOD OF GLOBAL DIFFERENTIATION. THE PROJECT WILL SUPPORT A POSTDOC AT THE CARNEGIE INSTITUTION OF WASHINGTON AND PROVIDE ANALYTICAL SUPPORT FOR A GRADUATE STUDENT AT NORTHWESTERN UNIVERSITY.