WE PROPOSE TO CARRY OUT COORDINATED PETROLOGIC MINERALOGICAL AND ISOTOPIC INVESTIGATIONS OF EARLY-FORMED NEBULAR CONDENSATES PRESERVED IN CHONDRITIC METEORITES IN HOPES OF BETTER CONSTRAINING THE EARLIEST ENVIRONMENTS IN THE SOLAR NEBULA. THIS PROJECT IS AIMED TO SHED LIGHT ON THE (ASTRO)PHYSICAL AND CHEMICAL PROCESSES THAT RESULTED IN THE FORMATION OF SOLAR SYSTEM S FIRST SOLIDS AND THE ISOTOPIC INVENTORIES IN WHICH THESE SOLIDS CONDENSED. THIS IS DIRECTLY RELEVANT TO THE GOALS OF EMERGING WORLDS SOLICITATION TO UNDERSTAND THE FORMATION AND EARLY EVOLUTION OF THE SOLAR SYSTEM AND THE RESEARCH AREAS OF STUDIES OF THE MATERIALS PRESENT AND PROCESSES THAT LED TO THE ONSET OF SOLAR SYSTEM FORMATION AND STUDIES OF ALL ASPECTS OF MATERIALS AND PROCESSES OCCURRING IN AND AFFECTING THE PROTOPLANETARY DISK INCLUDING THOSE OCCURRING ON BODIES OF ANY SIZE THAT MAY HAVE FORMED AT THIS STAGE OF SOLAR SYSTEM EVOLUTION . CA-AL-RICH INCLUSIONS (CAIS) ARE THE OLDEST DATEABLE SOLIDS IN THE SOLAR SYSTEM WITH A RADIOMETRIC AGE OF 4.567 BILLION YEARS DETERMINED ON A FEW LARGE CAIS. IN THIS PROPOSED WORK WE PLAN TO STUDY TWO SUBTYPES OF CAIS. THE FIRST SUBTYPE NAMELY FINE-GRAINED CAIS CONSISTS OF AGGREGATES OF MICRON-SIZED DUST THAT DIRECTLY CONDENSED OUT OF THE NEBULAR. THEREFORE THE CHEMICAL AND ISOTOPIC CHARACTERISTICS OF THE FINE-GRAINED CAIS REFLECT THE CONDITIONS OF THE NEBULAR GAS IN WHICH THESE CAIS FORMED. THE SECOND SUBTYPE OF CAIS WHICH ARE ALSO EARLY NEBULA CONDENSATES IS HIBONITE ( CORUNDUM) BEARING INCLUSIONS. THEY ARE THERMODYNAMICALLY PREDICTED TO BE THE FIRST MINERAL PHASES DIRECTLY CONDENSING FROM A COOLING GAS OF SOLAR COMPOSITION AROUND 1600 1770 K AT ~10-3 BAR. SUCH INCLUSIONS PROVIDE AN EXCELLENT OPPORTUNITY TO STUDY THE ENVIRONMENT IN THE HOTTEST STAGE OF THE SOLAR SYSTEM HISTORY; HOWEVER THEY HAVE NOT BEEN WELL STUDIED DUE TO THEIR RARITY AND SMALL SIZES (USUALLY 50 MICRONS OR LESS). IN THIS PROPOSAL WE WILL FOCUS ON THE CO 3.0 CHONDRITES AS THEY ARE KNOWN TO BE MORE PRISTINE AND HAVE BEEN REPORTED TO HAVE MORE ENRICHED IN FINE-GRAINED CAIS AND HIBONITE ( CORUNDUM) BEARING INCLUSIONS THAN OTHER GROUPS OF CARBONACEOUS CHONDRITES. OUR COLLABORATORS PROF. BREARLEY DRS. KROT KELLER AND HAN HAVE IDENTIFIED SOME FINE-GRAINED CAIS AND HIBONITE ( CORUNDUM) BEARING INCLUSIONS IN CO3.0 CHONDRITES. WE WILL ALSO PERFORM IN-SITU SEARCHES FOR MORE OF THESE RARE INCLUSIONS AND PETROLOGICAL STUDIES OF THEM ON THICK SECTIONS WITH SCANNING ELECTRON MICROSCOPY FOLLOWED BY OXYGEN ISOTOPIC MEASUREMENTS WITH THE NEW CAMECA IMS-1290 AT UCLA TO BETTER CONSTRAIN THE OXYGEN ISOTOPE RESERVOIRS IN THE GAS. ONCE THE OXYGEN ISOTOPE ANALYSES ARE FINISHED MEASUREMENTS FOR 26AL-26MG (CHRONOLOGY) AND 10BE-10B (IRRADIATION HISTORIES OF DUST AND GAS) SYSTEMS WILL BE ALSO PERFORMED ON THE IMS-1290 ION MICROPROBE BY USING A RADIO-FREQUENCY OXYGEN ION SOURCE WHOSE SMALL YET INTENSE PRIMARY ION SPOT WILL ALLOW FOR ISOTOPE ANALYSIS OF INDIVIDUAL PHASES WITHIN A SMALL INCLUSION. WHEN ISOTOPIC ANALYSIS IS ACCOMPLISHED PECULIAR SAMPLES (E.G. CARRY UNUSUAL ISOTOPIC ANOMALIES) WILL BE SENT TO OUR COLLABORATORS LABORATORIES FOR TRANSMISSION ELECTRON MICROSCOPY (TEM) STUDY. A COMPREHENSIVE PICTURE OF THE FORMATION ENVIRONMENTS OF FINE-GRAINED CAIS AND HIBONITE ( CORUNDUM) BEARING INCLUSIONS WILL BE CONSTRUCTED BY USING ALL THE MINERALOGY PETROLOGY AND ISOTOPIC CHARACTERISTICS OBTAINED IN THIS PROPOSED WORK.