THERMAL AND ALTERATION HISTORY OF THE CV PARENT ASTEROID(1) TO UNDERSTAND THE ACCRETIONARY AND THERMAL HISTORIES OF THE CV CHONDRITE PARENT ASTEROID WE PROPOSE TO CONSTRAIN THE INITIAL 26AL/27AL RATIO IN THIS BODY BY MEASURING INTERNAL 26AL-26MG ISOCHRONS IN 2030 CHONDRULES FROM THE LEAST METAMORPHOSED CV3 CHONDRITES INCLUDING KABA Y-980145 AND Y-86009 BY THE UH CAMECA IMS-1280 SECONDARY ION MASS-SPECTROMETER (SIMS). TO IDENTIFY OTHER WEAKLY METAMORPHOSED CV3S WE WILL USE OPTICAL AND SCANNING ELECTRON MICROSCOPY (SEM) ELECTRON MICROPROBE ANALYSIS (EPMA) AND RAMAN SPECTROSCOPY. THE ESTIMATED INITIAL 26AL/27AL RATIO IN THE CV PARENT ASTEROID WILL BE USED FOR ITS THERMAL MODELING. OUR PRELIMINARY DATA ON THE INFERRED INITIAL 26AL/27AL RATIOS IN 8 KABA (CV3.1OXB) CHONDRULES SUGGEST THAT THE INITIAL ABUNDANCE OF 26AL IN THE CV ASTEROID MAY BE ENOUGH TO EXPLAIN THERMAL METAMORPHISM EXPERIENCED BY CVS BUT COULD BE TOO LOW TO MELT THIS ASTEROID. VARIATIONS IN THE INFERRED INITIAL 26AL/27AL RATIOS IN CV CHONDRULES WILL BE ALSO USED TO UNDERSTAND THE NUMBER OF CHONDRULE GENERATIONS THAT ACCRETED ON THE CV ASTEROID. (2) TO UNDERSTAND THE ALTERATION HISTORY OF THE CV ASTEROID WE PROPOSE TO STUDY SECONDARY MINERALIZATION IN CV3S OF DIFFERENT PETROLOGIC SUBTYPES USING OPTICAL MICROSCOPY SEM EPMA ELECTRON BACKSCATTER DIFFRACTION (EBSD) RAMAN SPECTROSCOPY AND FOCUSED ION BEAM + TRANSMISSION ELECTRON MICROSCOPY (FIB+TEM). THERMODYNAMIC MODELING OF THE IDENTIFIED SECONDARY MINERAL PARAGENESES WILL BE USED TO CONSTRAIN PHYSICO-CHEMICAL CONDITIONS OF ALTERATION. (3) TO UNDERSTAND THE CHRONOLOGY OF CV ALTERATION WE PROPOSE TO STUDY 53MN-53CR SYSTEMATICS IN SECONDARY FAYALITE IN SEVERAL WEAKLY METAMORPHOSED CV3OXB. THE 53MN-53CR AGES OF FAYALITE IN CV3OXB WILL BE COMPARED WITH THOSE OF KIRSCHSTEINITE IN THE REDUCED CV3S AND IN CA FE-RICH SILICATE RIMS AROUND ALLENDE DARK INCLUSIONS. TO DEFINE MN-CR RELATIVE SENSITIVITY FACTORS FOR FAYALITE AND KIRSCHSTEINITE WE HAVE ALREADY SYNTHESIZED MN CR-BEARING FAYALITE AND KIRSCHSTEINITE CRYSTALS. OUR PRELIMINARY DATA INDICATE THAT FAYALITE AND KIRSCHSTEINITE IN CV CHONDRITES FORMED ~34 MA AFTER CV CAIS. WE WILL ALSO CHECK 55MN/52CR RATIO IN OTHER SECONDARY CA-FE-RICH SILICATES INCLUDING HEDENBERGITE AND ANDRADITE. IF THEIR RATIOS ARE HIGH ENOUGH FOR SIMS MEASUREMENTS OF 53MN-53CR SYSTEMATICS WE WILL SEARCH FOR SUITABLE TERRESTRIAL STANDARDS OR SYNTHESIZE THEM. (4) TO CONSTRAIN O-ISOTOPE COMPOSITIONS OF THE SECONDARY MINERALS (D17O AND D18O) AND OF THE FLUID (D17O AND POSSIBLY D18O) ON THE CV ASTEROID AND TO UNDERSTAND A ROLE OF THIS FLUID IN O-ISOTOPE EXCHANGE IN ANORTHITE AND MELILITE IN REFRACTORY INCLUSIONS AND CHONDRULES WE PROPOSE TO STUDY O-ISOTOPE COMPOSITIONS OF ANDRADITE ANORTHITE DMISTEINBERGITE FAYALITE HEDENBERGITE KIRSCHSTEINITE MAGNETITE NA-RICH MELILITE NEPHELINE SODALITE AND WOLLASTONITE IN CVS BY SIMS. TO DEFINE INSTRUMENTAL MASS-FRACTIONATION EFFECTS FOR THESE MINERALS WE WILL MEASURE BULK O-ISOTOPE COMPOSITIONS OF TERRESTRIAL MINERALS AND EVALUATE WHETHER THEY ARE SUITABLE AS STANDARDS FOR O-ISOTOPE MEASUREMENTS OF THE SECONDARY MINERALS IN CV AND CK CHONDRITES BY SIMS. OUR PRELIMINARY DATA ON FAYALITE AND MAGNETITE IN KABA INDICATE THAT D17O OF THE CV FLUID WAS ~1.5 . TO UNDERSTAND POSSIBLE EFFECTS OF METASOMATIC ALTERATION ON OISOTOPE COMPOSITIONS OF PRIMARY MINERALS WE WILL STUDY O-ISOTOPE COMPOSITIONS OF PLAGIOCLASE AND MELILITE IN CHONDRULES AND REFRACTORY INCLUSIONS FROM KABA Y-980145 AND Y-86009. OUR PRELIMINARY DATA INDICATE THAT PLAGIOCLASE IN CHONDRULES AND REFRACTORY INCLUSIONS FROM KABA EXPERIENCED EXTENSIVE O-ISOTOPE EXCHANGE WITH AN ASTEROIDAL FLUID. (5) TO UNDERSTAND A POSSIBLE GENETIC RELATIONSHIP BETWEEN THE CV AND CK CHONDRITES WE PROPOSE TO STUDY SECONDARY MINERALIZATION IN THE LEAST METAMORPHOSED CK3S INCLUDING WATSON 002 NWA 2921 4425 AND 4724 USING EPMA SEM+EBSD AND FIB+TEM AND COMPARE IT WITH SECOND